ELECTRICAL HIGH-VOLTAGE CURRENT INTERRUPTION DEVICE, INSTALLATION CONDUCTING SUCH A DEVICE, CONTROL METHOD AND METHOD FOR EVALUATING THE INTEGRITY OF AN ELECTRICAL CONDUCTOR

Description

Technical Field

[0001] The invention relates to the field of high-voltage direct current (HVDC) electrical current interruption devices and their control methods. Such devices are intended to be implemented in HVDC network units in the event of an electrical fault occurring in an electrical conductor of that network unit.

[0002] High-voltage direct current (HVDC) grid units are being considered as a solution for interconnecting disparate or asynchronous power generation sites, particularly to increase energy transmission capacity between countries (interconnections between countries) via what are known as energy highways. HVDC grid units are also being considered for the transmission and distribution of energy generated by wind farms rather than AC technologies, due to lower line losses and the absence of parasitic capacitance impacts within the grid unit over long distances. Such HVDC grid units typically operate at voltage levels of 100 kV and above.

[0003] In this text, for a device carrying a high-voltage direct current, a high-voltage device is considered either a "high-voltage A" device, in which the rated operating voltage is direct current and greater than 1500 V but less than or equal to 75,000 V (75 kV), or a "high-voltage B" device when the rated operating voltage is direct current and greater than 75,000 V (75 kV). Thus, the high-voltage direct current domain includes both the "high-voltage A" and "high-voltage B" domains.

[0004] The interruption of high-voltage direct current in such networks or network units is a crucial issue directly conditioning the feasibility and development of such networks.

[0005] Generally, in the field of high-voltage direct current (DC) or alternating current (AC) systems, at each end of an electrical conductor, there is an electrical disconnect device capable of interrupting the flow of electrical current in the conductor. This current can be the rated current, which is the maximum current the conductor is capable of carrying under steady-state conditions, or a fault current, which can exceed this rated current. In the event of a fault, the electrical grid is designed to implement a fault-clearing strategy aimed at interrupting the current in the faulty electrical conductor. Interrupting electrical currents under high-voltage direct current (HVDC) is more complex than interrupting currents under alternating current (AC).Indeed, when an alternating current is interrupted, a zero-crossing of the current is used to perform the power cut, which is not possible with direct current, particularly HVDC. In the event of a fault, the electrical network is designed to implement a fault-clearing strategy, aimed at interrupting the current in the faulty electrical conductor. Technique antérieure

[0006] Most currently planned HVDC network units will use buried or submarine cables as electrical conductors, as obtaining rights of way for overhead conductors is difficult. However, overhead conductors from existing overhead lines, designed for alternating current, could be upgraded and subsequently used in HVDC network units as electrical conductors, which would be an attractive solution due to both its simplicity and cost-effectiveness.

[0007] Each of these two types of electrical conductors can, in service, experience electrical faults.

[0008] The probability of fault occurrence is higher for overhead conductors, particularly due to their exposure to harsh weather conditions, such as lightning strikes. Indeed, a lightning strike on an overhead conductor produces overvoltages that can temporarily affect the dielectric properties of the insulators and lead to insulation failure. This necessarily necessitates isolating the conductor in which the fault occurred by opening a disconnect device from the rest of the network. Generally, a given conductor is equipped with a disconnect device at each of its two ends, and in the event of a fault, both disconnect devices are opened to isolate the conductor, and thus isolate the fault from the rest of the HVDC network unit.After the conductor has been isolated and the air deionized, it can be reconnected to the HVDC network unit, since faults caused by lightning strikes are very often non-persistent. This process is called automatic re-closure, which involves closing the disconnecting device(s) that were opened to isolate the conductor. However, other fault scenarios could cause a permanent insulation failure. In this case, automatic re-closure would result in a second fault on the conductor and would require reopening the disconnecting device(s) used to isolate it. Generally, the power grid operator sets a maximum number of successive re-closure attempts that can be made after a faulty conductor has been isolated.These successive re-closing attempts are conducted within a short period of time to minimize the time during which the conductor is unavailable. Of course, successive re-closing attempts on a conductor with a permanent fault are bound to fail, and this succession of attempts leads to a number of problems concerning network stability and increases stress on the switching device, such as: disturbances in the HVDC network unit; an interruption or disturbance of power flow that may lead to instability of any AC network units connected to this network unit; high requirements for high energy absorption in a short time, for example in surge arresters; a significant thermal impact on the components of any adjacent electrical power converters, especially on the freewheeling diodes of such converters.

[0009] The aforementioned problems arise from the fact that, prior to automatic re-closure, the conductor's condition is unknown. Consequently, the main problem to be solved is assessing the persistence of the fault on the conductor. Research has shown that fault re-occurrence is more likely at voltage levels close to the nominal voltage. Thus, a fault may not manifest itself at low voltage levels (see, for example, G. Ebner, W. Hartmann, M. Hergt and S. Wietzel, "Fault arc extinction and system re-start on HVDC transmission fines using LCC or VSC full-bridge converters with integrated arc recovery simulation models," 13th IET International Conference on AC and DC Power Transmission (ACDC 2017), Manchester, 2017, pp. 1-5, doi: 10.1049 / cp.2017.0018).This implies that a reliable assessment is only possible when the conductor is fully charged, i.e. when its electrical potential is brought to a potential that represents a significant proportion of its electrical potential in nominal operation.

[0010] It has already been proposed to place, in series with the conductor, an insertion resistance device consisting of a resistor in parallel with a short-circuit switch. There are solutions in which the insertion resistance device is integrated into the circuit breaker (see, for example, J. Shu, S. Wang, T. Liu, "A Soft Reclosing Model for Hybrid DC Circuit Breaker in VSC-MTDC System," 2018 IEEE 4th South. Power Electron. Conf., pp. 1-5, 2018). In normal operation, the resistor is bypassed by keeping the short-circuit switch in its closed state. After the faulty line is isolated by the circuit breaker, the short-circuit switch in parallel with the resistor opens.During the re-closing of the disconnecting device, an initial inrush current is observed due to the potential difference between the HVDC network unit and the conductor that was previously isolated and discharged through the fault. In the case of a non-permanent fault, the presence of the insertion resistor in series with the conductor limits the inrush current and thus reduces disturbances in the HVDC network unit. Furthermore, the insertion resistor limits the overvoltage in the conductor when the incoming voltage waveform is reflected at twice its nominal value, assuming an open circuit at the other end of the conductor. In the case of automatic re-closing on a persistent fault, the insertion resistor can also limit the fault current and therefore the voltage across the disconnecting device.However, even though the impact of automatic re-closing on a persistent fault is less pronounced with an insertion resistor, there is still a disturbance on the DC-energized network side, and wear on the components. Furthermore, no prediction is made before the automatic re-closing process begins.

[0011] In the document Vinothkumar, K., Segerqvist, I., Johannesson, N., & Hassanpoor, A., (2016), "Sequential auto-reclosing method for hybrid HVDC breaker in VSC HVDC links", "2016 IEEE 2nd Annual Southern Power Electronics Conference (SPEC)", pp. 1-6, the proposed solution is based on a hybrid DCCB with several sub-modules connected in series. The hybrid DCCB consists of a main branch, a main breaking branch, and an energy absorption branch. The main branch contains an ultrafast disconnector (UFD) and a load switching switch (LCS) in series. The main breaking branch contains a stack of IGBT modules. In parallel with each stack, a surge limiter (SA) absorbs energy during the opening sequence. Once the faulty overhead conductor has been isolated and the deionization time has elapsed, the system is re-closed. (200ms-500ms) has elapsed, the proposed automatic re-closing sequence unfolds as follows: 1. Sequential closure of the disconnect modules to gradually increase the voltage on the overhead conductor side; 2. Verification of fault persistence using a fault detection algorithm; 3. If the fault persists, all disconnect modules reopen.

[0012] This process is repeated until the maximum number of attempts, defined by the network operator, is reached. To prevent unacceptable thermal overheating of the surge arresters (SAs), the document proposes alternating the choice of switching modules to be closed. However, this solution requires an ultra-fast, hybrid-type circuit breaker due to the rapid operating time required in the event of a persistent fault. Furthermore, the surge arresters (SAs) must be designed to withstand such energy absorption. The proposed solution still risks causing a complete re-closure on a still-present fault because no assessment of the overhead conductor's condition is performed before the complete re-closure, which also leads to wear on the components.

[0013] Document WO2018162421 describes a method for closing a circuit breaker (10) having a main branch (M), which includes a main module comprising a sub-branch including a mechanical disconnect switch (UFS) connected to two circuit breaker cells made of a duty-cycle power semiconductor element, the main branch (M) being connected to a pre-insertion module. The circuit breaker (10) and the pre-insertion module form an assembly having a first (111) and a second (112) terminal, respectively connected to a source (S) and to the power transmission link (C). In parallel with the main branch, there is a parallel arm (Arm) comprising two thyristors in opposite directions and a capacitor in parallel with both a resistor and a switch. Finally, also in parallel with the main branch, there is an energy absorption branch (Ex) which is implemented here in the form of a surge arrester (SA3).

[0014] The process includes the following steps: a) to first close the mechanical switch-disconnector (UFS) when the voltage difference between the voltages at the first and second terminals is less than a predefined voltage; b) to close the bypass switch (S2); and c) to close the power semiconductor element.

[0015] During the opening sequence, the fault current is redirected from the main branch to the parallel arm by turning on the thyristor in the parallel arm and then opening the mechanical disconnect switch (MCS). This is possible because the capacitor has been initially discharged. Once charged to the protection voltage of the MCS, the magnetic energy is absorbed, forcing the fault current to zero. Before the re-closing sequence begins, the capacitor must be discharged by the parallel resistor. The re-closing sequence starts with the closing of the thyristor in the parallel arm, resulting in a current that charges both the capacitor and the transmission line. In the event of a persistent fault, the capacitor continues to charge until it reaches the surge protector's protection voltage, and the remaining energy is absorbed by the SA3 surge protector.The advantage of this solution is that the mechanical disconnect switch (UFS) does not need to be reopened since the current flows directly through the parallel arm. However, in the event of a persistent fault, the initial current remains high because the reopening occurs on a discharged capacitor with no resistance. Furthermore, the condition of the transmission line is not assessed before reopening.

[0016] The document by S. Zhang, G. Zou, B. Li, B. Xu, and J. Li, "Electrical Power and Energy Systems Fault property identification method and application for MTDC grids with hybrid DC circuit breaker," published in "Electr. Power Energy Syst.", vol. 110, no. January, pp. 136-143, 2019, describes yet another solution implementing a hybrid circuit breaker. The proposed device includes an auxiliary circuit for this hybrid circuit breaker. The main circuit consists of several sub-modules in series. Each sub-module comprises an IGBT module in parallel with a snubber circuit, which essentially consists of a small capacitor and a small resistor in parallel with a diode. The idea is to interconnect the sub-modules so that the capacitor is used to send tripping signals (10 to 20% of the nominal voltage) into the line.In a subsequent step, fault persistence is identified using a wavelet transform algorithm that analyzes the reflected traveling waves created either by the fault or by the open circuit at the far end of the line. The auxiliary circuit includes at least one thyristor between each sub-module, a grounding resistor Rg, and a fast grounding switch (FMS). The proposed solution aims to assess the fault state of the transmission line before re-closure. However, several problems remain. The solution sends low-amplitude trigger signals that do not provide reliable information because the fault can reappear after complete re-closure, once the line voltage returns to near the nominal voltage.The intention is clearly to analyze the trip signal and not to power the line, so there will still be a significant current during complete re-closure on the discharged transmission line. Furthermore, the proposed solution is highly limited to the specific architecture of the hybrid disconnect device described.

[0017] Document WO-2014 / 166528 describes a device comprising a capacitor 104 located in a branch between ground and an intermediate point on the main line. This intermediate point is arranged between a disconnect switch 102 and an isolation switch 126. The sole purpose of this capacitor 104 is to store energy to create a current oscillation through the disconnect switch 102, thereby interrupting an electric arc when it opens. The branch containing the capacitor 104 is intended to be part of an oscillation loop 103 when the switch 106 is closed. This oscillation loop generates the current oscillation capable of extinguishing the arc in the disconnect switch 102. This document focuses primarily on the opening of the disconnect switch 102.

[0018] Document EP-3.089.301 describes a device for injecting a countercurrent through the disconnect switch 110 regardless of the direction of the fault current. This document also addresses the opening of the disconnect switch 110.

[0019] The invention therefore aims to provide a device and a method which make it possible to secure the re-closing sequence of a switching device which has been previously opened to isolate a conductor of an electrical line arranged downstream of this switching device, in particular in the case of an overhead conductor of an overhead electrical power transmission line. Exposé de l'invention

[0020] To this end, the invention proposes a high-voltage direct current interruption device comprising: a main circuit, in which a nominal direct current flows in a conduction configuration of the switching device, the main circuit extending between an upstream point intended to be electrically connected to a high-voltage direct current source and a downstream point intended to be electrically connected to a conductor of a downstream power line; at least one first switching module comprising at least one switching switch interposed in the main circuit between a first primary point and a first secondary point of the main circuit, the first primary point and the first secondary point being located in that order in the main circuit between the upstream point and the downstream point, and the switching switch being capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the first switching module;an isolation switch, interposed in the main circuit between the upstream point and the first primary point, the isolation switch being capable of being controlled between an open state and a closed state. ;

[0021] The switching device includes a pre-charge circuit extending from the first primary point to earth (52) and comprising at least one pre-charge capacitor, at least one pre-charge resistor and a pre-charge switch.

[0022] The disconnecting device has at least: a charging configuration in which the pre-charge switch is in a closed state so that the pre-charge capacitor, pre-charge resistor and pre-charge switch are all electrically in series in the pre-charge circuit between the first primary point and ground, while the first primary point is electrically isolated from the downstream point of the switching device but electrically connected to the upstream point to allow charging of the pre-charge capacitor;a pre-charge configuration in which the pre-charge switch is in its closed state such that the pre-charge capacitor, the pre-charge resistor, and the pre-charge switch are all electrically in series in the pre-charge circuit between the first primary point and earth, while the first primary point is electrically isolated from the upstream point of the disconnect device but electrically connected to the downstream point to allow discharge of the pre-charge capacitor into the downstream power line conductor; an isolation configuration in which the first primary point is isolated from the upstream point, with the isolation switch in its open state, and is isolated from the downstream point, with the disconnect switch in its open state.

[0023] In the conduction configuration, the pre-charge switch is open to isolate the first primary point from ground, and the upstream point is electrically connected to the downstream point by the main circuit comprising the cutoff switch and the isolation switch both in their closed state.

[0024] The invention also proposes such a device with the following optional characteristics, taken individually or in combination.

[0025] The first breaking module may include a breaking assistance circuit which extends electrically in parallel with the breaking switch and the main circuit between the first primary point and the first secondary point of the main circuit, and, in a breaking configuration, the breaking device may then be configured such that at least one pre-charge capacitor of the pre-charge circuit is part of the breaking assistance circuit of the first breaking module.

[0026] The switching device may include, downstream of the first switching module in the main circuit of the switching device, at least one last switching module comprising at least one switching switch interposed in the main circuit between a last primary point, downstream of the first secondary point, and a last secondary point of the main circuit, and the switching switch of the last switching module being capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the last switching module.

[0027] The last breaking module may include a breaking assistance circuit which extends electrically in parallel from the breaking switch of the last breaking module and the main circuit, between the last primary point and the last secondary point of the main circuit, and, in a breaking configuration, the breaking device may be configured such that at least one pre-charge capacitor of the pre-charge circuit is part of the breaking assistance circuit of the last breaking module.

[0028] The pre-charge circuit may include at least one first pre-charge capacitor and at least one second pre-charge capacitor, and, in a cutoff configuration, the cutoff device may be configured such that the first pre-charge capacitor is part of the cutoff assist circuit of the first cutoff module while the second pre-charge capacitor is part of the cutoff assist circuit of the last cutoff module.

[0029] The switching device may include, in the main circuit of the switching device, between the first switching module and the last switching module, at least one additional switching module comprising at least one switching switch interposed in the main circuit between an additional primary point, downstream of the first secondary point, and an additional secondary point of the main circuit, upstream of the last primary point, and the switching switch of the additional switching module being capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the additional switching module.

[0030] An additional breaking module may include a breaking assistance circuit which extends electrically in parallel with the breaking switch of the additional breaking module in question and the main circuit between the additional primary and secondary points of the main circuit which correspond to the additional breaking module in question, and, in a breaking configuration, the breaking device may be configured such that at least one pre-charge capacitor of the pre-charge circuit is part of the breaking assistance circuit of the additional breaking module.

[0031] The disconnecting device may include a single disconnecting module whose disconnecting assistance circuit includes, successively and in this order from the first primary point, at least one pre-charge capacitor and an activation switch, with a tapping point between the two in the disconnecting assistance circuit, the pre-charge circuit may include a first section, which is common with the disconnecting assistance circuit, which extends between the first primary point and the tapping point and which includes at least one pre-charge capacitor, and the pre-charge circuit includes a second section, separate from the disconnecting assistance circuit, which extends between the tapping point and earth and in which the pre-charge switch is interposed.

[0032] The switching device may include at least one upstream switching module and one downstream switching module whose switching assistance circuits are, in the switching configuration of the switching device, electrically arranged in series;The downstream cutoff module's cutoff assistance circuit may include, successively and in this order from the downstream primary point, at least one pre-charge capacitor and an activation switch, with a tapping point between the two in the cutoff assistance circuit, and the pre-charge circuit may include a first section extending from the upstream primary point to the tapping point, which is common with the series cutoff assistance circuits, and which includes at least one pre-charge capacitor from each of the series cutoff assistance circuits, and the pre-charge circuit may include a second section, separate from the cutoff assistance circuits, extending from the tapping point to ground and in which the pre-charge switch is interposed.

[0033] The current interruption device may include a bypass circuit which extends, in electrical parallel with the main circuit, between the first primary point and a bypass point arranged between the last secondary point and the downstream point, and in which is interposed a bypass switch which is in a closed state in the pre-charge configuration and in an open state in the load, isolation and interruption configurations.

[0034] The cutoff device may include a configuration switch which is arranged in the main circuit between the last secondary point and the bypass point, and which is in an open state in the pre-charge and charge configurations, and in a closed state in the conduction and cutoff configurations.

[0035] The switching device may include at least one shunt switch which, in the charging configuration and in the pre-charging configuration, is in a closed state to connect in series, in the pre-charging circuit, the pre-charging capacitors belonging to the different switching modules.

[0036] The breaking switch of a breaking module may comprise a primary, mechanical switch and a secondary, mechanical switch, interposed successively in the main circuit between the primary point and the secondary point corresponding to the breaking module under consideration, but on either side of an intermediate point of the main circuit corresponding to the breaking module under consideration, the two mechanical switches each being controlled between an open state and a closed state, and this breaking module may comprise a primary surge arrester arranged in parallel with the primary switch between the primary point and the intermediate point corresponding to the breaking module under consideration, and a secondary surge arrester arranged electrically in parallel with the secondary switch between the intermediate point and the secondary point corresponding to the breaking module under consideration.and the circuit assisting the interruption of this particular interruption module may extend electrically in parallel with the assembly formed by the primary and secondary switches of this particular interruption module, and electrically in parallel with the assembly formed by the primary and secondary surge protectors of this particular interruption module.

[0037] The downstream power line may include an overhead line, the conductor of the downstream power line being an overhead conductor.

[0038] The invention also relates to an electrical installation according to claim 13.

[0039] The invention further relates to a method for controlling the closing of such a current interruption device, the interruption device being initially in the isolation configuration, characterized in that the control method comprises at least one conductor pre-charge step during which the interruption device is brought into its pre-charge configuration to energize a conductor of a downstream power line downstream of the downstream point (38), and in that the closing control method comprises, during or after the conductor pre-charge step, at least one parameter determination step comprising the determination of at least one current or voltage parameter in the main circuit or in the downstream power line, and a decision step, during which it is decided, based on the at least one parameter determined during the parameter determination step,of whether or not the complete closure of the current interruption device continues by transitioning the current interruption device to the conduction configuration.

[0040] The invention also proposes such a control method with the following optional characteristics, taken individually or in combination.

[0041] Thus, in such a process it can be predicted that, in order to reach the conduction configuration, the pre-charge switch is opened before the closing of the cut-off switch and the isolation switch.

[0042] In such a process, if the decision step is not positive, it can be predicted that the process continues, without going through the conduction configuration of the switching device, by a pre-charge capacitor charging step during which the switching device is brought into the charging configuration, then successively by a new conductor pre-charge step, a new parameter determination step, and a new decision step, according to a pre-charge cycle.

[0043] The pre-charge capacitor recharging step may include: the closing of the isolation switch and the closing of the pre-charge switch to charge the pre-charge capacitor, keeping the cutoff switch in its open state; after said closing of the pre-charge switch, the reopening of the isolation switch.

[0044] The number of pre-charge cycles for a given attempt to re-close the cut-off device can be limited.

[0045] After at least one conductor pre-charge stage, complete closure of the current interruption device by switching the interruption device to its conduction configuration can be pursued if a voltage value in the main circuit, or in the downstream power line, exceeds a threshold value.

[0046] The invention further proposes an evaluation process according to claim 19. Brève description des dessins

[0047] [ Fig. 1 ] There figure 1 is a schematic general view of an electrical current transmission and distribution installation comprising a multi-terminal HVDC current network unit in which a device and method according to the invention can be implemented. [ Fig. 2 ] There figure 2 represents a point-to-point HVDC current network unit in which a device and method according to the invention can be implemented. [ Fig. 3 ] There figure 3 represents a slightly more detailed, yet still schematic and simplified, view of part of the installation 10, illustrating the environment of a disconnection device of an HVDC network unit conforming to the teachings of the invention. [ Fig. 4A-4B ] THE figures 4A et 4B These are simplified diagrams of part of the installation 10 which is illustrated in the Fig. 3 , illustrating the isolation configuration of the switching device and a preparation configuration. [ Fig. 5A-5B ] THE figures 5A et 5B These are simplified diagrams of part of the installation 10 which is illustrated in the Fig. 3 ,illustrating a control sequence of the switching device including its transition from a preparation configuration to its pre-charge configuration. [ Fig. 6A-6D ] THE figures 6A à 6D These are simplified diagrams of part of the installation 10 which is illustrated in the Fig. 3 , illustrating a control sequence of the switching device including its passage through a pre-charge capacitor charging configuration. [ Fig. 7A-7C ] THE figures 7A à 7C These are simplified diagrams of part of the installation 10 which is illustrated in the Fig. 3 , illustrating a control sequence of the switching device including its transition to a conduction configuration. [ Fig. 8 ] There figure 8 is a schematic flowchart of an electrical protection process including a method for controlling the closing of a switching device 28according to the invention. [ Fig. 9A ] There figure 9A illustrates another embodiment of a cutting device according to the invention. [ Fig. 9B ] There figure 9B is a table indicating the switching states of the various switches in the circuit breaker device Fig. 9A , in different configurations of this switching device. [ Fig. 10A ] There figure 10A illustrates another embodiment of a cutting device according to the invention. [ Fig. 10B ] There figure 10B is a table similar to that of the Fig. 9B for the cut-off device of the Fig. 10A . [ Fig. 11A ] There figure 11A illustrates another embodiment of a cutting device according to the invention. [ Fig. 11B ] There figure 11B illustrates a variant of the cut-off device of the Fig. 11A according to the invention. [ Fig. 11C ] There figure 11C is a table similar to that of the Fig. 9B for the switching devices Figs. 11A et 11B . [ Fig. 12A ] There figure 12A illustrates another embodiment of a cutting device according to the invention. [ Fig. 12B ] There figure 12B is a table similar to that of the Fig. 9B for the cut-off device of the Fig. 12A [ Fig. 13A ] There figure 13A illustrates another embodiment of a cutting device according to the invention. [ Fig. 13B ] There figure 13B is a table similar to that of the Fig. 9B for the cut-off device of the Fig. 13A . [ Fig. 14A ] There figure 14A illustrates another embodiment of a cutting device according to the invention. [ Fig. 14B ] There figure 14B is a table similar to that of the Fig. 9B for the cut-off device of the Fig. 14A . [ Fig. 15A ] There figure 15A illustrates another embodiment of a cutting device according to the invention. [ Fig. 15B ] There figure 15B is a table similar to that of the Fig. 9B for the cut-off device of the Fig. 15A . [ Fig. 16A ] There figure 16A illustrates another embodiment of a cutting device according to the invention. [ Fig. 16B ] There figure 16B is a table similar to that of the Fig. 9B for the cut-off device of the Fig. 16A . [ Fig. 17A ] There figure 17A illustrates another embodiment of a cutting device according to the invention. [ Fig. 17B ] There figure 17B is a table similar to that of the Fig. 9B for the cut-off device of the Fig. 17A . Description des modes de réalisation

[0048] There Fig. 1 represents an example of an installation 10 for the transmission and distribution of electric current comprising a high-voltage direct current (HVDC) power grid unit, hereinafter referred to as the HVDC grid unit 12. The HVDC network unit 12 operates under a single rated service voltage which is a high DC voltage, for example with a rated DC service voltage greater than 75,000 V (75kV).

[0049] In an electrical network, the transmission of electrical power between two given points of the network is carried out by a power transmission line which generally comprises several conductors, each corresponding to an electrical pole of the power transmission line. In all cases, for the purposes of this text, an electrical conductor can be in the form of a single electrical conductor extending between two distinct points of a given network unit, or in the form of a set of electrical conductors extending in parallel between two distinct points of a given network unit, all conductors of the set being, at any given instant, at the same electrical potential for the same position between the two distinct points along each of these conductors (this is to take into account any potential voltage drop along each given conductor due to the conductor's resistivity).

[0050] Thus, in an HVDC network unit, the transmission of electrical power between two given points in the network is achieved via a power transmission line which, in many cases, has two electrical poles, each pole comprising an electrical conductor extending between the two given points in the network. In this case, the power transmission line therefore consists of two electrical conductors of different polarities, with, for example, one electrical conductor at a positive potential and the other at a negative or neutral potential.Still within an HVDC network unit, the transmission of electrical power between two given points in the network can also be achieved via a three-pole power transmission line comprising three electrical conductors, with one conductor at a positive potential, one at a negative potential, and one at a neutral potential. In some cases, the transmission of electrical power between two given points in the network can be achieved via a single-pole power transmission line, with one electrical conductor at the line potential and a return path to earth.

[0051] In the Figs. 1 et 2 , A single line represents a power transmission line between two distinct points of a network unit, particularly in the HVDC network unit. 12,This is to clearly illustrate the network topology without going into technical details. Similarly, where an electrical bus is represented at a given point on the network unit, in reality there will be as many electrical buses as there are poles, and therefore as many electrical buses as there are electrical conductors in the transmission lines originating from that point. For example, we can assume that we have represented HVDC on the network unit. 12 only electric conductors and electric buses corresponding to a positive pole.

[0052] In the example of the Fig. 1 , the HVDC network unit 12 features 4 terminals, in this case a first terminal 14.1, a second terminal 14.2, a third terminal 14.3 and a fourth terminal 14.4. The HVDC network unit 12includes electrical conductors to connect these 4 terminals 21, 22, 23, 24, electric buses 26.1, 26.2, 26.3, 26.4, switching devices, etc... all of which operate at the nominal operating voltage of the HVDC network unit 12.

[0053] There Fig. 2 represents another example of an installation 10 electrical current transmission and distribution system comprising an HVDC network unit 12. In this second example, the HVDC network unit 12 presents 2 terminals, in this case a first terminal 14.1 and a second pair of terminals 14.2. The HVDC network unit 12 includes, for electrically connecting these 2 terminals, a single electrical line comprising an electrical conductor 21 which extends electrically between two electrical power converters 18.1, 18.2, with interposition, at each end of the electrical conductor 21,cutting devices 28.1, 28.2 which operate under the nominal service voltage of the HVDC network unit 12.

[0054] In each of its 4 terminals, the HVDC network unit 12 of the Fig. 1 , is connected to another network unit 16.1, 16.2, 16.3, 16.4. In the example, each of these other network units 16.1, 16.2, 16.3, 16.4 is a network unit under alternating current voltage, so that each of the 4 terminals 14.1, 14.2, 14.3 And 14.4 is actually connected to the DC side of an AC-DC power converter 18.1, 18.2, 18.3, 18.4. However, one or more of these other network units 16.1, 16.2, 16.3, 16.4, could be of a different nature, and could, for example, be another HVDC network unit. Each of these other network units 16.1, 16.2, 16.3, 16.4 can be a unit of electricity generation network (e.g., a wind farm), and / or a unit of electricity transmission and distribution networks.

[0055] In the example illustrated in the Fig. 1 , the HVDC network unit 12 includes several connection nodes, in this case 3 connection nodes, here implemented in the form of electrical buses 26.1, 26.3 et 26.4, each of which comprises at least three distinct connections which are electrically connected to each other continuously, that is to say without the possibility of electrical interruption between the connections.

[0056] The linking node 26.1 illustrated at Fig. 1 is implemented in the form of an electric bus and includes a first connection 26.11 which is electrically connected to a proximal end of a first electrical conductor 21 of a first power transmission line of the electrical network unit in question, with the interposition of a first electrical disconnection device 28.11, associated with the first link 26.11,which has an open state and a closed state. In its closed state, the first electrical disconnection device 28.11 allows the circulation of an initial power flow between the considered connection node and the first conductor 21, in the first connection 26.11. This first power flow corresponds, under normal operating conditions and in the absence of faults, to that which flows in the first conductor 21. In its open state, the first electrical cut-off device 28.11 interrupts the flow of all electrical power between the considered connection node and the first conductor 21, in the first connection 26.11.

[0057] Generally, an electrical switching device can include one or more current-interrupting devices, such as switches, arranged in parallel and / or in series between an input point and an output point. In the open state, an electrical switching device prevents current from flowing through it. In the closed state, an electrical switching device allows current to flow through it. An electrical switching device can include one or more circuit breaker-type devices, optimized to interrupt an established current, and / or one or more disconnector-type devices, optimized to maintain electrical isolation between its two terminals when open. Such devices can be mechanical, electronic, or hybrid. However, in the example, the first electrical switching device 28.11is preferably of the mechanical type, in which the electrical break corresponds to a mechanical separation of two electrodes.

[0058] On the Fig. 1 , we can see that the first electrical conductor 21 is connected, at its distal end, to the fourth terminal 14.4 of the HVDC network unit 12, here via a fourth electric bus 26.4 of the HVDC network unit 12. In this example, an electrical cutoff device 28.41 is interposed between the distal end of the first electrical conductor 21 and a connection 26.41 of the fourth electric bus 26.4. Preferably, especially for reasons of reduced cost, the electrical cut-off device 28.41 is a mechanical type electrical disconnect device. Thus, the first electrical conductor 21is capable of being completely isolated, at each of its two ends, by means of a mechanical electrical disconnect device which ensures the interruption of the power flow between the first electrical conductor 21 and the rest of the infrastructure. In the specific example of the Fig. 1 , the fourth terminal 14.4 is electrically connected to a fourth other electrical network unit 16.4.

[0059] Although not shown on the Fig. 1 , it is possible to provide, at the ends of this first conductor 21, For example, at each end of this first conductor, a protective inductance, which can be implemented as a dedicated inductive component, such as a coil. Such protective inductances act as inductive current limiters and may be required, in particular, if the first conductor 21presents in itself a low equivalent inductance. As is known, other parameters can be taken into account to determine the need for the presence of such a protective inductance, such as the type and / or number of adjacent conductors connected to other links of the node under consideration, and / or the number and / or power of the electrical power converter(s) connected to other links of the node under consideration.

[0060] The linking node 26.1 illustrated at Fig. 1 includes a second bond 26.12 which, in this example, is electrically connected to a second electrical conductor 22, belonging to a second power transmission line of the HVDC network unit 12, via a second electrical disconnection device 28.12. In the example of the Fig. 1 , we can see that this second electrical conductor 22is connected, at its distal end, to the third terminal 14.3 of the HVDC network unit 12, here via a third electric bus 26.3 of the HVDC network unit 12. In this example, an electrical cutoff device 28.31 is interposed between the distal end of the second electrical conductor 22 and a connection for the third electric bus 26.3.

[0061] The linking node 26.1 illustrated the Fig. 1 also includes a third connection 26.13. In this example, the third bond 26.13 is electrically connected to another electrical network unit. The passage of a third electrical power flow is permitted through the third connection. 26.13. This third power flow is controlled by at least one third electrical switching device 28.13,associated with the third bond, which has an open state and a closed state. In the example of the Fig. 1 , We note that a power cut-off device 29.1, which will be referred to as an external disconnection device in relation to the HVDC network unit 12 considered, is electrically arranged between the electrical power converter 18.1 to the first other electrical network unit 16.1 and that same other electrical network unit 16.1 Strictly speaking. In the case where the other external unit is an AC voltage network, the external disconnection device 29.1 is a switching device under alternating voltage.

[0062] The linking node 26.1 illustrated at Fig. 1 includes a fourth link 26.4 which is electrically connected to a third electrical conductor 23of a third power transmission line of the HVDC network unit 12, with the interposition of a fourth electrical disconnection device 28.14. In the example, we see that this third electrical conductor 23 is connected, at its distal end, to the second terminal 14.2 of the HVDC network unit 12, with the interposition of an electrical disconnect device 28.22.

[0063] In the example illustrated in the Fig. 1 , we can see that the second terminal 14.2 is connected within the HVDC network unit 12, only at the first terminal 14.1 the HVDC network unit 12, here by the third electrical conductor 23. Conversely, in the example illustrated in the Fig. 1 , the HVDC network unit 12 includes another electrical conductor 24 which is connected, at one end, to the third terminal14.3 of the HVDC network unit 12, here via an electrical disconnect device 28.32. This other electrical conductor 24 is connected, at its second end, to the fourth terminal 14.4 of the HVDC network unit 12, here via an electrical disconnect device 28.42.

[0064] We therefore note that the HVDC network unit 12 of the Fig. 1 is a network unit that is meshed, in the sense that it has at least two points, here two terminals, which are electrically connected by two electrical paths that are at least partially distinct. Thus, we understand that, in the example of the Fig. 1 , in normal operation of the HVDC network unit 12, Electrical power can be transmitted between two terminals, here the first terminal 14.1 and the fourth terminal 14.4along two electrical paths that are at least partially distinct. However, the HVDC network unit can take other configurations, for example a star network unit, or even, as in the example of the Fig. 2 , take the form of a point-to-point network unit.

[0065] In what follows, it will be assumed that an electrical fault has occurred in the first electrical conductor. 21, leading to the opening of the first electrical disconnection device 28.11. It should be noted here that, with regard to the Fig. 1 , It is by arbitrary choice that we choose to describe the situation of a fault in the first electrical conductor 21, and that one could similarly describe the situation of a fault in one of the other electrical conductors of the HVDC network unit 12, for example in the second electrical conductor 22.

[0066] We have represented on the Fig. 3 a first example of the implementation of a switching device 28 in accordance with the teachings of the invention.

[0067] In this Fig. 3 , We have illustrated that such a cutting device 28 is intended to be used in an electrical installation with a high-voltage direct current source 17 electrically connected to at least one conductor 21 of a downstream power line, which may include an overhead line. In the example of the Fig. 3 , the high voltage direct current source 17 includes, for example, as seen above in relation to the Fig. 1 , an electrical power converter 18 which is also powered by another network unit 16, for example, an AC network unit. The switching device 28is intended to be interposed between the high-voltage direct current source 17 and the driver 21 of the downstream power line. As part of an installation according to the Fig. 1 , the shut-off device 28 of the Fig. 3 may correspond, for example, to one or the other of the switching devices 28.11, 28.12, 28.14, 28.22, 28.31 28.32, 28.41, 28.42 of the Fig. 1 which are connected to an electrical conductor of a power transmission line without the interposition of another disconnecting device. In the context of an installation according to the Fig. 2 , The shut-off device 28 of the Fig. 3 may correspond, for example, to one or the other of the switching devices 28.1, 28.2 which are respectively connected to the electrical conductor of the power transmission line.

[0068] The shut-off device 28, designed to interrupt a high-voltage direct current electrical current, it includes a main circuit34, in which circulates, in a conduction configuration C_COND of the switching device, a rated current which is, for example, greater than 500 Amps, or even greater than 1000 Amps, under a rated continuous operating voltage which is, for example, greater than 75,000 volts. The main circuit 34 of the disconnecting device 28 extends between an upstream point 36 of the main circuit, which is intended to be electrically connected to the high-voltage direct current source 17, and a downstream point 38 of the main circuit, which is intended to be electrically connected to the conductor 21 of a downstream power line. In some cases, there will be no interposition of another disconnecting device between the downstream point 38 and the driver 21,or, for example, at the very least, no interposition of another disconnecting device playing a role in a process of assessing the integrity of an electrical conductor during the closing of the disconnecting device. 28.

[0069] The shut-off device 28 includes at least one first cutoff module 40.1 including at least one disconnect switch 42.1 which is interposed in the main circuit 34 between a first primary point 44.1 and a first secondary point 46.1 of the main circuit 34.The first switching module is represented here in a simplified manner by a simple switch. In reality, those skilled in the art know that, in the field of high-voltage direct current, such a switching switch can be combined with other elements to effectively perform its primary function of interrupting the current. For example, a switching switch may have primary and secondary contacts electrically connected in parallel. A switching switch may also include arc-extinguishing means. This will be illustrated in the following sections. figures 9A and following that, within a switching module, a switching switch can be associated with a switching assistance circuit. The following description of the embodiment of the Fig. 3encompasses all these possibilities, which will not be detailed insofar as the operating principle described is not affected by the possible presence of such additional equipment in the cut-off module.

[0070] The first primary point 44.1 and the first secondary point 46.1 are located in that order in the main circuit 34 between the upstream point 36 and the downstream point 38. In the example of the Fig. 3 , the switching device is represented with a single switching module 40.1, but we will see later that the cutting device 28 may include several switching modules interposed successively in the main circuit 34 between the upstream point 36 and the downstream point 38. Typically, the cut-off switch 42.1is likely to be controlled between an open state and a closed state to determine respectively an open state and a closed state of the first breaking module. Typically, the breaking switch 42.1 acts as a circuit breaker. As we will see later, the disconnect switch 42.1 a switching module can be formed of several switches arranged in series and / or in parallel to ensure the function of switching current.

[0071] The shut-off device 28 also includes an isolation switch 48 which is interposed in the main circuit 34 of the disconnecting device 28 between the upstream point 36 and the first primary point 44.1, the isolation switch 48 being capable of being controlled between an open state and a closed state. Typically, the isolation switch 48acts as a disconnect switch. Of course, nothing prevents the installation of other switches in the main circuit. 34 of the disconnecting device 28 between the upstream point 36 and the first primary point 44.1, whether they are switches acting as a disconnector or playing another role.

[0072] As can be seen on the Fig. 3 , the shut-off device 28 includes a pre-charge circuit 50 which extends between the first primary point 44.1 and the earth 52 and which includes at least one pre-charge capacitor 54, at least one pre-charge resistor 56 and a pre-charge switch 58. We will see that different arrangements are possible for the pre-charge capacitor. 54, the pre-charge resistance 56 and the pre-charge switch 58 in the pre-charge circuit 50.In the example of the Fig. 3 , successively, the pre-charge circuit is found 50, starting from the first primary point 44.1 towards the earth 52, First, the pre-charge switch 58, then the pre-charge resistance 56, then the pre-charge capacitor 54. We will see in other examples that we can also have, successively in the pre-charge circuit 50, starting from the first primary point 44.1 towards the earth 52, first the pre-charge capacitor 54, then the pre-charge resistance 56, then the pre-charge switch 58. According to other variations, we could have the pre-charge resistance 56 between the pre-charge capacitor 54 and the earth 52. Other variations are still possible, for example by reversing the position of the pre-charge capacitor. 54and pre-charge resistance 56. The pre-charge capacitor 54 It can, for example, comprise a single physical component, or be made up of several distinct physical components arranged in series and parallel in the form of a capacitive system electrically equivalent to a capacitor 54 illustrated.

[0073] Depending on whether the various switches are open or closed, the disconnecting device 28 presents different configurations, which allow the cutting device 28 to perform various functions with respect to the HVDC network unit 12. In the figures 4A-4B ; 5A-5B ; 6A-6D ; 7A-7D We illustrated different switching sequences for the various switches, thus implementing different configurations of the switching device. 28.

[0074] First, the shut-off device 28presents an insulation configuration C_ISOL in which the first primary point 44.1 is isolated from the upstream point 36, with the isolation switch 48 in its open state, and is isolated from the downstream point 38, with the cut-off switch 42.1 in its open state. In this configuration, which is the one illustrated in the Fig. 3 , the downstream point 38 is therefore electrically isolated from the upstream point 36. In this way, the electrical conductor 21 of the power transmission line, which is connected to the downstream point 38, is electrically isolated from the voltage source 17 which is connected to the upstream point 36. In embodiments with multiple switching modules, it is preferable that, in the insulation configuration C_ISOL, all the switching modules must be in their open state. Similarly, when a switching module contains a switch formed by several successive switching switches in the main circuit 34 (see the examples described later with reference to Fig. 9A, 9B , 13 And 14A ), all the module's disconnect switches are preferably in their open state when the disconnecting device is in its isolation configuration C_ISOL.

[0075] Preferably, when the cut-off device 28 is in its insulation configuration C_ISOL, the pre-charge switch 58 is in its open state. However, it is understood that, at least in the implementation mode of the Fig. 4B , the pre-charge switch 58 could be in its closed state, without this calling into question the fact that the first primary point 44.1either electrically isolated from the upstream point 36 and the downstream point 38, nor, consequently, the fact that the electrical conductor 21 of the power transmission line, which is connected to the downstream point 38, either electrically isolated from the voltage source that is connected to the upstream point 36.

[0076] In a conduction configuration C_COND, the shut-off device 28 allows the nominal electrical current to flow through the switching device 28, from the upstream point 36 at the downstream point 38, therefore from the voltage source 17, 18 to the electrical conductor 21 of the power transmission line. The principle of this conduction configuration C_COND is, for the cut-off device of the Fig. 3 , illustrated at Fig. 7C . For this purpose, the isolation switch 48, and the cutoff switch42.1 are both in their closed state. Of course, in embodiments with multiple switching modules, in the conduction configuration C_COND, all the cut-off modules 40.1, 40.2, ..., 40.n, are in their closed state. Similarly, when a switching module includes a switch formed by several successive switching switches in the main circuit 34, all the module's cutoff switches are in their closed state when the cutoff device 28 is in its conduction configuration C_COND. In contrast, in the conduction configuration C_COND, the pre-charge switch 58 is open to isolate the first primary point from the ground.

[0077] The shut-off device 28 can also be configured in a loading configuration C_CH which aims to electrically charge the pre-charge capacity54 of the pre-charge circuit 50. The principle of this loading configuration C_CH is, for the cut-off device of the Fig. 3 , illustrated at Figure 6C . In the loading configuration C_CH, the pre-charge switch 58 is in a closed state so that the pre-charge capacitor 54, the pre-charge resistance 56 and the pre-charge switch 58 are all electrically connected in series in the pre-charge circuit 50 between the first primary point 44.1 and the earth 52, while the first primary point 44.1 is electrically isolated from the downstream point 38 of the disconnecting device 28 but electrically connected to the upstream point 36 to allow the pre-charge capacitor to charge. Indeed, in this configuration, the electrical energy from the voltage source 17to which the upstream point is connected 36 is likely to charge the pre-charge capacitor 54. For this purpose, the isolation switch 48 is in its closed state and the cutoff switch 42.1 is in its open state. Of course, in embodiments comprising several switching modules interposed successively in the main circuit 34 of the disconnecting device 28, it will be anticipated that, in the loading configuration C_CH, at least one cutoff module must be in an open state. It is possible to anticipate that several cutoff modules, or even all of them, may be open. 40.1, 40.2, ..., 40.n , are in their open state. Similarly, when a switching module includes 40.1, 40.2, ..., 40.n , a switch formed by several successive breaking switches in the main circuit 34,at least one disconnect switch, or even all the disconnect switches in the module, are in their open state when the disconnect device 28 is in its loading configuration C_CH. Similarly, if there is another switch between the first primary point 44.1 and the voltage source 17, These will be in their closed state.

[0078] The shut-off device 28 can also be configured in a pre-charge configuration C_PCH to allow the pre-charge capacitor to discharge into the conductor 21 of the downstream power line. In the pre-charge configuration C_PCH of the disconnecting device 28, the pre-charge switch 58 is in its closed state so that the pre-charge capacitor 54, the pre-charge resistance 56 and the pre-charge switch 58are all electrically connected in series in the pre-charge circuit 50 between the first primary point 44.1 and the earth 52, while the first primary point 44.1 is electrically isolated from the upstream point 36 of the disconnecting device 28 but electrically connected to the downstream point 38. For this purpose, the isolation switch 48 is in its open state and the cutoff switch 42.1 is in its closed state. Of course, in embodiments with multiple switching modules, in the pre-charge configuration, all switching modules 40.1, 40.2, ..., 40.n, are in their closed state. Similarly, when a switching module includes a switch formed by several successive switching switches in the main circuit 34, all the module's cutoff switches are in their closed state when the cutoff device 28is in its pre-charge configuration C_PCH. The pre-charge configuration C_PCH is, for the cut-off device of the Fig. 3 , represented at the Fig. 5B .

[0079] We are indeed considering the case where the electrical conductor, arbitrarily the first electrical conductor 21 of the Fig. 1 or of the Fig.2 , was previously the site of an electrical fault which resulted in its electrical isolation, by opening the disconnecting devices at its two ends.

[0080] In the following, the upstream disconnecting device is the one of these two disconnecting devices located at the upstream end of the electrical conductor. 21, so between the driver 21 which was the subject of the electrical fault and the source of voltage 17.Therefore, the downstream disconnecting device is the one of these two disconnecting devices that is located at the downstream end of the electrical conductor. 21. In the example of the Fig. 1 , We can assume that the upstream disconnecting device is, for the first electrical conductor 21, the shut-off device 28.11, the downstream disconnection device was then in place for this first electrical conductor 21, the shut-off device 28.41. For a given electrical conductor, the distinction between upstream and downstream depends on which end of that conductor is connected to what can be considered a high-voltage direct current source. In some installations, for a given electrical conductor in a power transmission line, the same end of the conductor will always be considered the upstream end. For example, in an installation like that of the Fig. 2 , one end of the electrical conductor 21 One end can be connected, for example, to a wind farm, while the other end can be connected, for example, to a distribution network and / or an electricity consumer. In this case, the end connected to the wind farm will be the upstream end. In other cases, which end of the electrical conductor is the upstream end may depend on the instantaneous state of the installation. For example, in an installation of the type illustrated in the Fig. 1 , which of the two ends of the first electrical conductor 21 The upstream end may depend on the state, for example, of other network units. 16.1, 16.4 which are respectively connected to each of the two ends of this first electrical conductor 21.

[0081] To the Fig. 3 , The upstream end of the electrical conductor has been illustrated. 21of the power transmission line, as being connected to what, at least at the moment of the line's re-closure, is considered a high-voltage direct current source 17. The shut-off device 28 illustrated at Fig. 3 is therefore considered, with respect to the process which will be described below, as an upstream shut-off device.

[0082] Such a disconnecting device can be used to implement a process for assessing the integrity of an electrical conductor. 21 in an electrical power transmission line in an electrical installation 10 including a primary high-voltage direct current source 17 electrically connected to the electrical conductor 21 with an upstream power cut-off device 28 interposed between the main voltage source 17 and the electrical conductor 21.

[0083] In an initial state, when the electrical conductor 21 is electrically isolated from the installation, the upstream disconnection device 28 is in an isolation configuration C_ISOL. Furthermore, the electrical conductor 21 is, at a distal end, connected to a downstream electrical disconnection device which, in its initial state, is in an isolation configuration C_ISOL so that, in its initial state, the electrical conductor is, except with regard to any possible electrical fault affecting the electrical conductor 21, electrically isolated from the installation 10 and the environment.

[0084] The envisaged evaluation process includes at least one pre-charge step for the electrical conductor 21 during which an auxiliary voltage source, separate from the main voltage source 17,is connected to the electrical conductor of the electrical power transmission line, to energize the electrical conductor 21 while keeping the electrical conductor isolated from the main voltage source 17 and in relation to the rest of the electrical installation 10.

[0085] We will see that, with a cutting device 28 according to the invention, for example that illustrated schematically in the Fig. 3 , The auxiliary voltage source is formed by at least one pre-charge capacitor 54 of the pre-charge circuit 50 such that the pre-charge stage of the electrical conductor 21 is achieved by bringing the upstream cut-off device into its pre-charge configuration C_PCH. Of course, care is then taken to maintain the downstream shut-off device in its isolation configuration. C_ISOL. However, in other embodiments of an evaluation process, the auxiliary source could include another electrical network, or a generator set, possibly with a power converter, but in all cases separate from the main voltage source. 17 which delivers the nominal operating voltage to the HVDC network unit 12.

[0086] The envisaged evaluation process includes, during or after the conductor pre-charge stage, at least one parameter determination stage comprising the determination of at least one current or voltage parameter in the downstream power line, and an evaluation stage during which the integrity of the electrical conductor is assessed. 21 is evaluated based on at least one parameter determined during the parameter determination step.

[0087] It is understood that, in the event of an electrical fault affecting the electrical conductor 21,The current or voltage parameter in the line will be noticeably different from that which would be found in the line in the absence of this fault. Typically, the electrical potential of the electrical conductor 21 will differ depending on whether or not an electrical fault affecting the electrical conductor is present during the implementation of the evaluation process. 21. For example, with an upstream shut-off device 28 in accordance with the teachings of the invention, and provided that, before the pre-charge stage, the pre-charge capacitor 54 belonging to the upstream disconnecting device has been previously charged; the conductor pre-charge stage results in a discharge of the electrical energy contained in the pre-charge capacitor. 54 to the electrical conductor 21. In this scenario, unless there is an electrical fault affecting the electrical conductor 21, the electrical conductor21 is located, on its downstream end, electrically isolated from the installation 10 and the environment. Therefore, the electrical potential of the electrical conductor 21, The result of discharging the pre-charge capacitor into the electrical conductor whose condition, and therefore integrity, we wish to assess will differ depending on the presence or absence of an electrical fault affecting that conductor. Therefore, the electrical potential of the electrical conductor must be evaluated. 21, From this, we can deduce an indication of the integrity of this electrical conductor. 21.

[0088] Preferably, the evaluation process is conducted by bringing in the electrical conductor 21whose integrity is to be evaluated at a test potential level whose value is, for example, greater than or equal to at least 50%, preferably greater than or equal to 70% of its nominal electrical potential in service, when the power line is subjected to the nominal service voltage of the HVDC network unit 12. Indeed, it has become apparent that at lower potential levels, an electrical fault is not necessarily detectable. For example, in the case of only a partial break in the electrical insulation surrounding the conductor, the electrical fault may only appear at a certain potential within the conductor. 21 which reaches at least the level of test potential described above.

[0089] To that end, we will see that, within the framework of using a disconnecting device 28according to the invention, for example one of those illustrated in the figures, comprising at least one pre-charge capacitor 54, It is possible, depending in particular on the capacitance value of the pre-charge capacitor 54 with respect to the characteristic impedance, in particular the equivalent capacitance, of the electrical conductor 21, that a single pre-charge step of the conductor may not be sufficient to reach the desired potential level. In this case, the evaluation process may then involve several successive pre-charge steps, separated by pre-charge capacitor charging steps 54, preferably while maintaining the electrical conductor 21 electrically isolated from the main voltage source 17, as will be described below, this is so as not to disrupt the latter in the event of a persistent electrical fault in the electrical conductor 21.Thus, if a pre-charge step fails to reach the desired test potential level, the evaluation process continues without going through the conduction configuration. C_COND of the power cut-off device, that is, without connecting the electrical conductor 21 whose integrity with the main voltage source we want to evaluate 17, by a pre-charge capacitor charging step during which the device is brought into the charging configuration C_CH, then successively, still without connecting the electrical conductor 21 whose integrity with the main voltage source we want to evaluate 17,by a new pre-charge step of the electrical conductor and a new parameter determination step, according to a pre-charge cycle. It should be noted that the current and / or voltage parameter determination step in the line, implemented to allow for the evaluation of the line's integrity, can be carried out after each pre-charge step, or possibly after a predetermined number of successive pre-charge steps.

[0090] Naturally, we will try to avoid increasing the number of pre-charge cycles required to assess the conductor's integrity. To achieve this, it is clear that the pre-charge capacitor needs to be sized appropriately. 54 such that the energy it is capable of accumulating allows, in a reasonable number of pre-charge cycles, for reaching, in the electrical conductor 21,the desired test potential level, which will, for example, be greater than or equal to at least 50%, preferably greater than or equal to 70% of the nominal electrical potential value in operation in the electrical conductor 21, when the power line is subjected to the nominal service voltage of the HVDC network unit 12.

[0091] For example, one could choose to size the pre-charge capacitor 54 such that the energy which it is capable of accumulating makes it possible to reach, in the electrical conductor 21, and assuming that the electrical conductor is not affected by an electrical fault, the desired test potential level in a single pre-charge, or in a number of pre-charge cycles in the range of 1 to 10, preferably in the range of 1 to 4.

[0092] Of course, this sizing will depend on the equivalent capacitance of the electrical conductor. 21.For example, the equivalent capacitance of the pre-charge capacitor 54 may be at least 10% of the equivalent capacity of the electrical conductor 21 (The equivalent capacitance of a conductor is the linear capacitance of the conductor multiplied by its length). In practice, the equivalent capacitance of the pre-charge capacitor 54 It may therefore be greater than 1 microfarad (µF), or even greater than 5 microfarads (µF).

[0093] By allowing for multiple pre-charge cycles to reach the desired test potential level, the equivalent capacitance of the pre-charge capacitor can be reduced. 54, Therefore, its size and cost are factors. Thus, a pre-charge capacitor will generally suffice. 54 having an equivalent capacitance of less than 20 microfarads (µF), or even in some cases an equivalent capacitance of less than 10 microfarads (µF).

[0094] The equivalent capacitance of the pre-charge capacitor 54 It will therefore be included in the range from 1 microfarad (µF) to 20 microfarads (µF), or even in the range from 5 microfarads (µF) to 20 microfarads (µF).

[0095] For example, in a single-conductor line, the following relationship can be used to determine the size of the equivalent capacitance C 54 of the pre-charge capacitor 54 : C 54 = C 21 1 − V 21 test V 12 n − C 21 With : C 21: the equivalent capacity of the driver 21 V 21test: the desired test potential level in the conductor 21 V 12: the nominal operating voltage in the HVDC network unit 12 n: a maximum number of pre-charge cycles that are allowed to be reached in the electrical conductor 21, the desired level of testing potential.

[0096] In all cases, the equivalent capacitance of the pre-charge capacitor 54can be determined and / or refined empirically, for example by numerical simulation or by some experimental tests.

[0097] In some embodiments, the pre-charge capacitor 54 must be able to withstand a voltage across its terminals that is at least equal to the nominal operating voltage in the HVDC network unit 12, for example, being able to withstand a voltage across its terminals that is within the range of 1 to 2 times the nominal operating voltage in the HVDC network unit 12. In some of the illustrated examples, the pre-charge capacitor 54 is integrated into a surge protection circuit in parallel with a surge protector. In such cases, the pre-charge capacitor 54must be able to withstand a voltage across its terminals equal to the surge protector's protection voltage, which is, for example, within a range of 1.5 to 1.7 times the nominal operating voltage in the HVDC network unit 12.

[0098] We will now describe a method for controlling the closing of an electrical current interruption device in accordance with the teachings of the invention. This method for controlling the closing includes a process for evaluating the integrity of the electrical conductor. This method for controlling the closing of an interruption device 28 is part of the general framework of an electrical protection process 100 a schematic organizational chart of which is illustrated in the Fig. 8 .

[0099] Different stages of the pilot closing process will be described with reference to figures 4A, 4B , 5A, 5B , 6A-6D et 7A-7D which schematically describe the different successive states of the switching device during such a control process.

[0100] As previously stated, the Fig. 4A describes the configuration of the cut-off device Fig. 3 , right after a preliminary step 120 electrical insulation of the electrical conductor 21 considered, for example, following detection 110 of an electrical fault in this electrical conductor 21. It is noted that, at the Fig. 4A , the pre-charge switch 58 is in its open state. However, as illustrated in the Fig. 4B , It could be expected that it would be in its closed state.

[0101] In this example, we will describe the case in which, just after the preliminary step 120 electrical insulation of the electrical conductor in question, the capacitor 54the pre-charge circuit is in a charged state. The voltage across the pre-charge capacitor is then considered to be 54 is equal to, or of the same order of magnitude as, the voltage between the electrical conductor 21 considered and grounded when the power transmission line is at its rated service voltage. If this is not the case, the first step of the closing pilot procedure can be analogous to the pre-charge capacitor recharging step. 54 which will be described below. Furthermore, before starting the step 141 Depending on the embodiments, it is possible to provide for a preparation process for the driver's preload. 130 an example of which will be described below.

[0102] In all cases, assuming that the capacitor 54 When the pre-charge circuit is in its charged state, at least one conductor pre-charge step is performed. 141including the passage of the shut-off device 28 to its pre-charge configuration C_PCH, described above and illustrated in the Figure 5B , to energize the electrical conductor of the electrical power transmission line which is arranged downstream of the downstream point 38 of the disconnecting device 28. Preferably, as illustrated by the succession of Figs. 5A et 5B , the driver pre-charge stage 141 first involves closing the pre-charge switch 58, and then the closure of the cutoff module(s) 40.1, 42.1.

[0103] During or after the driver pre-charge stage 141, in any case, once the pre-charge capacitor 54 was put into electrical communication with the power line, the evaluation process 140 includes at least one step 143parameter determination including the determination of at least one current or voltage parameter in the main circuit 34 or in the downstream power line. The minimum parameter to be determined may, for example, include or be selected from: the current intensity in the main circuit 34 or in the downstream power line, particularly in the first conductor 21, the time derivative of the current intensity in the main circuit 34 or in the downstream power line, particularly in the first conductor 21, the electrical potential of the first conductor 21, and / or the time derivative of the electric potential of the first conductor 21, or among their logical and / or arithmetic combinations.

[0104] The electrical potential of the first conductor 21can typically be determined via the voltage between this first conductor 21 and the earth, or through the voltage between this first conductor 21 and another conductor, in particular another conductor from the same electrical power transmission line.

[0105] Typically, the parameter to be determined is measured, or determined from a measurement. Thus, as represented on the Fig. 2 , The first electrical conductor is preferably equipped 21 and / or the main circuit 34 of the disconnecting device 28 of a measuring device 32.1, 32.2 delivering a measurement result used to determine the parameter. The measuring device may include, in particular, a voltmeter and / or an ammeter. Note that, in some cases, the parameter may be measured or determined from a measurement in the connection of a connecting node to which the electrical conductor21 is connected via the disconnect device 28.

[0106] As illustrated in the example shown in the Fig. 8 , we can anticipate within the evaluation process 140, a delaying step 142 between the passage 141 of the disconnecting device 28 to its pre-charge configuration and the step 143 parameter determination. This timing step 142 can be planned, for example, to wait for the stabilization of electrical conditions in the electrical conductor 21. This can, for example, be advantageous when the parameter to be determined is a parameter related to the final electrical potential in the electrical conductor, resulting from the pre-charge of the conductor by passing through the switching device. 28 to its pre-charge configuration C_PCH. Such a delaying step 142For example, it can have a duration between 1 ms and 20 ms milliseconds. However, in other embodiments, for example, embodiments in which the parameter to be determined relates to a variation in current or electrical potential in the electrical conductor 21, It may be advantageous to avoid such a delay and to complete the step 143 parameter determination immediately after the passage of the cutting device 28 to its pre-charge configuration C_PCH, for example to monitor the derivative of the current or electrical potential in the electrical conductor 21 at the time of current establishment, including through the analysis of transient or oscillatory phenomena during the stage 141 driver pre-charge.

[0107] As mentioned above, based on this parameter, the evaluation process 140 may include a step 144electrical conductor integrity assessment 21. Typically, this evaluation stage 144 The process may involve comparing the determined parameter with a threshold value, which may be predetermined or calculated based on the conditions under which the evaluation step takes place. This threshold value may be the desired test potential level described above, or it may be another value. Indeed, if the parameter's threshold value is reached or exceeded, it can be inferred that the electrical conductor is not, or is no longer, affected by an electrical fault, thus resulting in a positive assessment of the conductor's integrity. 21. In some cases, the value determined for the parameter will allow us to deduce that the electrical conductor remains affected by an electrical fault, thus resulting in a negative assessment of the electrical conductor's integrity. 21.In some cases, the value determined for the parameter will allow us to deduce that the electrical conductor remains affected by an electrical fault, thus resulting in a negative assessment of the electrical conductor's integrity. 21, even after a single pre-charge step of the electrical conductor. However, in some cases, the value determined for the parameter does not allow us to conclude anything about the integrity of the electrical conductor. For example, this situation may arise where the determined parameter does not indicate the presence of a fault, but the electrical potential reached in the electrical conductor 21 following the pre-charge stage, the electrical potential value of the test was not reached.

[0108] Thus, typically, after at least one step 141of conductor pre-charge, the complete closure of the current interruption device by transitioning the current interruption device to its conduction configuration C_COND is continued if a voltage value in the main circuit 34 of the disconnecting device 28, or in the downstream power line, exceeds a threshold value.

[0109] In general, the process for controlling the switching device may include a decision step, during which it is decided, based on at least one parameter determined during the parameter determination step, whether or not to proceed with the complete closure of the current switching device by switching the current switching device to the conduction configuration. C_COND. Typically, this decision-making step regarding the continuation of the complete closure results in a positive decision to proceed if the assessment of the electrical conductor's integrity has been carried out and is positive. Conversely, this decision-making step regarding the continuation of the complete closure results in a negative decision to proceed if the assessment of the electrical conductor's integrity has not been carried out or is negative.

[0110] In the illustrated example, the evaluation stage and the decision stage are one and the same stage. 144. For example, this step may involve comparing the electrical potential value of the first conductor. 21, determined at the determination stage 143, and a threshold value, for example the desired test potential level described above.

[0111] Of course, either or both the evaluation and decision stages can be based on the determination of several parameters. Furthermore, it is possible that the evaluation and decision stages will be based on the determination of different parameters, or on partially different sets of parameters.

[0112] If the decision to prosecute is positive, then the process initiates a prosecution. 160 of the complete closure of the shut-off device 28.

[0113] An example of a process 160 of continuing the complete closure of the shut-off device 28 is illustrated by the succession of Figs. 7A à 7C . According to this example, the cutting device 28 for example, it passes from the state of the Fig. 7A , corresponding to the disconnecting device 28 in its pre-charge configuration C_PCH, in the state of the Fig. 7C corresponding to the disconnecting device 28 in its conduction configuration C_COND. Preferably, as illustrated in the Fig. 7B , This can be done, in particular, by first planning the opening 161 of the pre-charge switch 58 before proceeding with the closure 163 of the isolation switch 48 of the disconnecting device 28 which allows the device to be brought into its conduction configuration C_COND. Note that, in the illustrated example, the isolation switch 48 is the one that is closed last to reach the conduction configuration C_COND.

[0114] To the Fig. 8 , the process 160 of continuing the complete closure of the shut-off device 28 ends with the stage 163 passage of the cutting device 28 to its conduction configuration C_COND. As described above, the process 160 of continuing the complete closure of the shut-off device 28 may include additional steps, including steps prior to the step 163 passage of the cutting device 28 to its conduction configuration C_COND. These additional steps 162 can, for example, allow a reconfiguration of the disconnection device 28, in particular to enable it to be ready for a new power outage in the event of the detection of an electrical fault affecting the electrical conductor 21.

[0115] As mentioned above, it can be anticipated that the decision to proceed with the complete closure of the shut-off device will be made. 28 be conditional on the step 144 electrical conductor integrity assessment 21could have been conducted under satisfactory conditions, particularly with regard to the electrical potential reached in the electrical conductor 21 following the pre-charge stage. If this electrical potential is insufficient to definitively determine the integrity of the electrical conductor, the decision stage may remain negative, without necessarily leading to the conclusion that the electrical conductor 21 would necessarily be affected by an electrical fault.

[0116] If the decision stage 144 If the result is negative, the process can continue without going through the conduction configuration. C_COND of the power cut-off device, by a step 180 pre-charge capacitor recharging during which the device is brought into the charging configuration C_CH, then successively through a new driver pre-charge stage 141,a new step in parameter determination 143, and a new stage of evaluation and / or decision-making 144, according to a new pre-charge cycle. It can be anticipated that this new pre-charge cycle will only be implemented if the evaluation step has not previously resulted in a negative assessment of the electrical conductor's integrity.

[0117] It is understood that this pre-charge cycle may be repeated several times successively as long as the evaluation and / or decision stage is not positive, therefore as long as the process does not continue through a process 160 complete closure of the shut-off device 28.

[0118] Preferably, the number of pre-charge cycles for a given attempt to re-close the cut-off device should be limited. 28.

[0119] This was represented at the Fig. 8 through a verification step 170the number of pre-charges performed. For example, each time the step 144 If the evaluation and / or decision is not positive, a counter can be incremented by one unit, and checked during the verification step. 170, that the value of this counter does not exceed a maximum value.

[0120] If the verification step 170 If the number of pre-charges performed reveals that a maximum number has been exceeded, the piloting process can be completed. 190, without having resulted in a complete re-closure of the shut-off device. Thus, if, after several pre-charge cycles, the decision step is negative, the closing pilot process is interrupted. In this case, it is preferable to bring the shut-off device to 28 in its insulation configuration C_ISOL. Generally, this hypothesis materializes when there is a persistent fault affecting the electrical conductor. 21,requiring intervention.

[0121] If the verification step 170 If the number of pre-charges performed reveals that a maximum number has not been exceeded, the control process can initiate a new pre-charge step. 141 of the driver 21, but after carrying out a recharging step 180 of the pre-charge capacitor 54.

[0122] Typically, the recharging step 180 of the pre-charge capacitor 54 understand : the closing of the isolation switch 48 and the closing of the pre-charge switch 58, by holding the cutoff switch 40.1, 42.1 in its open state, to charge the pre-charge capacitor 54, as illustrated in the Fig. 6C ; after the pre-charge switch has closed, the isolation switch has reopened 48, as illustrated in the Fig. 6D .

[0123] As a preliminary step, starting with the pre-charge configuration C_PCH as illustrated in the Fig. 6A , we will have opened at least one cutoff module 40.1, as illustrated in the Fig. 6B , before switching the cut-off device to its charging configuration illustrated in the Fig. 6C .

[0124] Above, we considered the case in which, just after the preliminary step 120 electrical insulation of the electrical conductor in question, the capacitor 54 of the pre-charge circuit 50 is in a charged state. However, in some embodiments, the implementation of the disconnection device 28 will do so, right after the preliminary step 120 electrical insulation of the electrical conductor in question, the capacitor 54the pre-charge circuit is in a discharged or insufficiently charged state. In this case, it is advantageous to provide that the control procedure includes, after the preliminary step 120 electrical insulation of the electrical conductor in question, but before a first pre-charge stage of the conductor 141, a preliminary step 132 recharging the pre-charge capacitor, for example within the preparation process 130. The preparation process 130 may also include other preparation steps 131.

[0125] There Fig. 3 illustrates a particularly simple embodiment of a cutting device according to the invention.

[0126] We will now describe embodiments of a switching device according to the invention that are more complex, while presenting the same general architecture as that of the Fig. 3 .

[0127] As we will see below, some of these methods of implementing a switching device 28 will include a single cutoff module 40.1 between the first primary point 44.1 and the downstream point 38. Other embodiments will include, downstream of the first switching module 40.1 in the main circuit 34 of the disconnecting device 28, at least one final cutoff module 40.n including at least one disconnect switch 42.n interposed in the main circuit 34 between a last primary point 44.n, downstream of the first secondary point 46.1, and one last secondary point 46.n of the main circuit 34. The cut-off switch 42.n of the last cutoff module 40.nis capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the last cutoff module 40.n. Among these embodiments comprising at least two successive switching modules in the main circuit 34 between the first primary point 44.1 and the downstream point 38, certain shut-off devices 28 will only have two cutting modules, between the first primary point 44.1 and the downstream point 38, namely, a first cutoff module 40.1 and a final cutoff module 40.n, the last breaking module then also being the second breaking module. Conversely, some breaking devices 28 will include, in the main circuit 34 of the disconnecting device 28, between the first cutting module 40.1 and the last cutoff module 40.n,at least one additional cutoff module 40.2, ..., including at least one disconnect switch 42.2, ..., interposed in the main circuit 34 between an additional primary point 44.2, ..., downstream from the first secondary point 46.1, and an additional secondary point 46.2, ..., of the main circuit 34, upstream of the last primary point 44.n, and the cutoff switch 42.2, ..., of the additional module 40.2, ..., being capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the additional cutoff module 40.2, ...,. Thus, such a cutting device 28may include a single additional switching module interposed in the main circuit between the first switching module and the last switching module, or several additional switching modules interposed successively in the main circuit between the first switching module and the last switching module.

[0128] We will see that, for two successive switching modules 40.i, 40.i+1 in the upstream-downstream direction in the main circuit 34, the primary point 44.i+1 The one downstream may be electrically confused with the secondary point 46.i of the one upstream, in the sense that the two points are always at the same electrical potential.

[0129] We will also describe embodiments in which the switching device 28 includes at least one cutoff module 40.i (i=1, 2, ..,) including a circuit for assisting the disconnection 70.i (i= 1, 2,...,) which extends electrically in parallel with the disconnect switch 42.i (i=1, 2, ..,) and the main circuit 34 between the first point primary point 44.i (i=1, 2, ..,) and a secondary point 46.i (i=1, 2, ..,) of the main circuit 34.

[0130] Such a circuit for assisting the shutdown 70.i is a device which, at the moment the cutoff module changes from its closed state to its open state, will facilitate the interruption of the electrical current through the cutoff switch 42.i of the cutoff module 40.i considered. Typically, such a circuit assists the disconnection 70.i will allow for a temporary reduction in the intensity of the electric current in the cutoff switch 42.ito which it is electrically connected in parallel, and may even, transiently, tend towards the cancellation, or the reversal of the direction of flow, of the electric current in the disconnect switch 42.i to which it is electrically connected in parallel. In such embodiments, it will be particularly advantageous that, in a switching configuration C_C, the shut-off device 28 be configured such that at least one pre-charge capacitor 54.i (i=1, 2, ..,) of the pre-charge circuit should also be part of the cut-off assistance circuit 70.i. Indeed, in this cutoff configuration C_C, the pre-charge capacitor 54.i will also be advantageously used to facilitate the switching function. In this way, the same electrical component, the pre-charge capacitor 54.iwill be used for two different functions, which will result in cost and size reduction for a switching device 28 having both a cut-off assistance circuit and a pre-charge circuit as described above.

[0131] In general, this can be implemented as follows. In each embodiment, for at least one switching module 40.i, a circuit to assist with the shutdown 70.i comprises, successively and in this order from the primary point 44.i associated with the module in question, at least one pre-charge capacitor 54.i and an activation switch 72.i with a stitching point 76 between the two in the cut-off assistance circuit 70.i. Thus, we can define the pre-charge circuit as having a first section, which is common with the cut-off assistance circuit. 70.i,which extends between the first primary point 44.1 and the stitching point 76 and which includes at least one pre-charge capacitor 54.i and a second section, separate from the cut-off assistance circuit 70.i, which extends between the stitching point 76 and the earth 52 and in which the pre-charge switch is interposed 58.

[0132] In the embodiments that will be described, the preparation process 130 within the piloting process may include a preparation step during which all current flow is cut off in the cut-off assistance circuit between the tapping point and the secondary point, for example using a switch placed between these two points.

[0133] We illustrated at the Fig. 9A a first embodiment of a switching device 28 including the cutoff module 40.1includes both a circuit for assisting the disconnection 70.1 and a pre-charge circuit 50 as described above. This embodiment comprises a single switching module 40.1 between the first primary point 44.1 and the downstream point 38. This example of the implementation of a disconnecting device 28 extends between an upstream point 36 and a downstream point 38 and can therefore be used in place of the embodiment illustrated in the Fig. 3 . Such a switching module is described in more detail in document WO 2020 / 136340, which can be consulted for a detailed description.

[0134] This single cutoff module 40.1 includes a cut-off switch 42.1 having a primary switch 60.1, mechanical, and a secondary switch 62.1, mechanical, interposed successively in the main circuit 34between the first primary point 44.1 and the first secondary point 46.1 associated with this single cutoff module 40.1, but on either side of a first intermediate point 64.1 of the main circuit 34 which corresponds to the cutoff module 40.1. The two primary mechanical switches 60.1 and secondary 62.1 can each be controlled between an open state and a closed state. Like the cutoff module 40.1 is unique here in the cutting device 28, the first secondary point 46.1 of the cutoff module 40.1 can be considered as electrically confused with the downstream point 38 of the disconnecting device 28, in the sense that the two points are always at the same electrical potential.

[0135] In this embodiment, the cutoff switch 42.1 includes: a primary surge protector 66.1arranged in parallel with the primary switch 60.1 between the first primary point 44.1 and the first intermediate point 64.1, a secondary surge protector 68.1 electrically arranged in parallel with the secondary switch 62.1 between the first intermediate point 64.1 and the first secondary point 46.1.

[0136] Such surge protectors limit the magnitude of the potential difference across the switch in parallel with which they are connected. Among surge protectors, lightning arresters are well-known, and these can include varistors and TVS (Transient Voltage Suppressor) diodes, such as Transil™ diodes. In particular, the primary surge protector 66.1 and / or the secondary surge protector 68.1 can each include a metal oxide varistor (or MOV, meaning "metal oxide varistor").

[0137] In this embodiment, the circuit for assistance with the disconnection 70.1 of the cut-off switch 42.1 extends between the first primary point 44.1 and the first secondary point 46.1 in the form of a capacitive buffer circuit that extends electrically in parallel with the assembly formed by the primary switch 60.1 and the secondary switch 62.1, and electrically in parallel with the assembly formed by the primary surge protector 66.1 and the secondary surge protector 68.1, and which includes an activation switch 72.1 and a buffer capacity which is formed here by the pre-charge capacitor 54.1. Preferably, in this embodiment, the capacitive buffer circuit forms a circuit for interruption assistance 70.1 does not include a dedicated inductive component. The capacitive buffer circuit forms a cutoff assistance circuit 70.1may include a tertiary surge protector 74.1 arranged in parallel with the activation switch 72.1, for example directly to the terminals of the activation switch 72.1.

[0138] We can see that the circuit for assistance with the cut-off 70.1 comprises, successively and in this order from the first primary point 44.1, at least one pre-charge capacitor 54.1 and an activation switch 72.1, with a stitching point 76 between the two in the cut-off assistance circuit 70.1. The pre-charge circuit 50 includes a first section, which is common with the cut-off assistance circuit, extending between the first primary point 44.1 and the stitching point 76 and which includes at least one pre-charge capacitor 54.1. The pre-charge circuit 50includes a second section, separate from the cut-off assistance circuit 70.1, which extends between the stitching point 76 and the earth 52 and in which the pre-charge switch is interposed 58. Note that the pre-charge resistance 56 of the pre-charge circuit 50 is arranged in the second section, separate from the cut-off assistance circuit 70.1, which extends between the stitching point 76 and the earth 52, therefore outside the circuit of the cut-off assistance 70.1. It is understood that, in this second section which extends between the point of staking 76 and the earth 52, the pre-charge resistance 56 of the pre-charge circuit 50 could be arranged on either side of the pre-charge switch.

[0139] It is noted that, in this embodiment, which includes a tertiary surge protector 74.1at the terminals of the activation switch 72.1, a configuration switch 78.1 is provided in the section of the cut-off assistance circuit that is separate from the pre-charge circuit 50. The configuration switch 78.1 is arranged between the tertiary surge protector 74.1 and the downstream point 38. This configuration switch 78.1 is closed in a cutoff configuration C_C of the disconnecting device 28, during which the circuit for assistance with the cut-off 70.1 is active to interrupt the flow of current through the cutoff switch 42.1 Opening. This configuration switch 78.1 is in its open state in the load configurations C_CH and preload C_PCH of the disconnecting device 28, to prevent the electrical conductor 21, connected to the downstream point 38,cannot discharge through the cut-off assistance circuit 70.1, particularly through the tertiary surge protector 74.1. Preferably, this configuration switch 78.1 is in its closed state in conduction configuration C_COND to anticipate a possible need to reopen the shut-off device 28.

[0140] In this embodiment, it is necessary that, in order to perform the switching, the pre-charge capacitor 54 either in a discharged state at the time it is desired to operate within the framework of the cutoff assistance. It is therefore necessary to provide a discharge circuit for the pre-charge capacitor 54.1. Such a discharge circuit (not shown in the figures) can be a passive discharge circuit, without any active components, for example including a discharge resistor arranged in parallel with the pre-charge capacitor. 54.Preferably, such a discharge resistor has a high electrical resistance value so that the dipole consisting of the pre-charge capacitor 54 and the discharge resistance arranged in parallel, exhibits a significant time constant compared to the electrical break-off delay in the secondary switch 62.1, for example a time constant greater than 50 milliseconds, preferably greater than 100 milliseconds. Another type of discharge circuit may include at least one active component, such as a controlled switch. Thus, a discharge circuit could include a controlled switch arranged directly in series electrically with the discharge resistor mentioned above, with both components connected in parallel with the pre-charge capacitor. 54.1.When the controlled switch is flipped to a closed state allowing current to flow, a discharge circuit will form between the two plates of the pre-charge capacitor. 54.

[0141] In a method of controlling a switching device 28 according to the Fig. 9A , In order to bring the device from its closed state to its open state, a step is planned which includes the mechanical opening of the primary switch. 60.1 and the secondary switch 66.1. The two switches can be opened mechanically simultaneously, or successively in any order. This opening of both switches can be triggered by an electrical fault in the electrical installation, particularly in the downstream conductor connected to the downstream point. 38. It is possible that the mechanical opening of the two switches 60.1, 66.1 of the cut-off switch42.1 does not, by itself, allow for electrical opening in the sense of interrupting the flow of current through the disconnecting device 10, due to the formation of an electric arc across each of the two switches 60.1, 66.1. In this scenario, the process involves cutting off the current in the primary switch. 60.1 opened to cause the appearance, at the terminals of the primary switch 60.1, of a voltage higher than the transition voltage of the primary surge protector 66.1 capable of switching it into a current conduction mode. To cut the current in the primary switch 60.1When open, an oscillation circuit such as those described in any of the documents WO-2020 / 136340, WO-2015 / 103857, EP-3.091.626, CN-103.296.636 and WO-2012 / 100831 may be used, combining in series a capacitor and a dedicated inductive component, to create an oscillating current to force a zero crossing of the current in the primary switch 60.1 Open. The power is out in the primary switch. 60.1 open can be achieved by other means, in particular by appropriately sizing the primary switch 60.1, even if this sizing results in a primary switch that is larger and / or more expensive than the one that could be used if an oscillation circuit were present. Once achieved, this interruption of the current through the primary switch 60.1 forces the current through the switching device 28 to charge the pre-charge capacitor 54.1,causing a voltage rise across its terminals, which in turn results in the appearance of the same voltage across the terminals of the primary surge protector 66.1, and therefore the same voltage across the terminals of the primary switch 60.1. In the event of a significant fault current, this voltage reaches the transition voltage of the primary surge suppressor 66.1, The resistance of this component then varies to limit the voltage increase, which reaches a plateau. At this stage, the primary surge protector is considered to be in operation. 66.1 becomes conductive to the current. Thus, we can consider that, from this moment on, the current through the switching device 28 passes through the primary surge protector 66.1 but continues to flow through the secondary switch 62.1 due to the presence of an electric arc between its contacts. To break the electric arc in the secondary switch62.1, The cut-off assistance circuit is activated by closing the activation switch. 72.1. We will assume that the configuration switch has already been brought to its closed state; otherwise, it can be done at this point. This allows, in the circuit for the interruption assistance, 70.1, the passage of a current specific to charging the pre-charge capacitor 54.1 and to relieve the current in the secondary switch 62.1. In its initial state, the pre-charge capacitor 54.1 is discharged, for example by the presence of the discharge circuit. In other words, the switching device 28 is configured so that, in the initial state, i.e., when the activation switch is flipped 72.1 to allow passage, in the cut-off assistance circuit 70.1, of a current suitable for charging the pre-charge capacitor 54.1, the pre-charge capacitor 54.1is discharged. Therefore, and due to the presence of a potential difference across the terminals of the primary surge protector 66.1, the current through the device 28 switch to the cut-off assistance circuit 70.1 to charge the pre-charge capacitor 54.1. During the pre-charge capacitor charging time 54.1, the current through the switching device 28 is essentially driven by the cut-off assistance circuit 70.1, This has the effect of reducing, or even stopping, the current flowing through the secondary switch. 62.1, It should be noted that it is in a state of mechanical interruption, with its contacts separated from each other. This decrease, or even cancellation, of the current through the secondary switch 62.1 will advantageously cause the extinction of the electric arc in the secondary switch 62.1.The secondary switch is then considered 62.1 is electrically open and a voltage can appear across its terminals without risk of reignition of the electrical arc. This voltage is transmitted to the terminals of the secondary surge protector 68.1, which can then play its role in limiting the voltage across the secondary switch. We can then consider that the switching device 28 is open, because only a leakage current can flow through the device 28 via the primary surge protector 60.1 and by the secondary surge protector 62.1. Therefore, it is wise to choose the primary surge protector. 60.1 and the secondary surge protector 62.1 such that the sum of their transition voltage is greater than the nominal voltage of the installation.

[0142] In the example, the pre-charge capacitor 54.1is the only capacitor in the cutoff assistance circuit 70.1, meaning that there is no capacitor in the section of the circuit that assists the disconnection 70.1 which is separate from the pre-charge circuit 50, here between the stitching point 76 and the secondary point 46.1. However, depending on the capacitance requirements for both the pre-charge operation and the cut-off assistance operation, it is possible to have, in addition to the pre-charge capacitor 54.1 which is arranged in the section of the pre-charge circuit 50 which is common with the cut-off assistance circuit 70.1, at least one other capacitor, this other capacitor being arranged in the section of the circuit that assists the disconnection 70.1 which is separate from the pre-charge circuit 50, here between the stitching point 76 and the secondary point 46.1.In all cases, the pre-charge capacitor 54.1 It can take the form of a single physical component, or be made up of several physical components that can be arranged electrically in series and / or in parallel to form a capacitive system electrically equivalent to a capacitor 54.1 illustrated.

[0143] For this embodiment of a switching device 28 illustrated at Fig. 9A , we illustrated at the Fig. 9B a table in which, for each of the configurations described above, a switching device is represented 28 According to the invention, the state of the various switches in the configuration shown. Each row of the table corresponds to one of these configurations, and the columns of the table correspond to the switches of the disconnecting device. 28,designated by the corresponding references used in the figures and in the text above. The open state is represented by the number 0, and the closed state is represented by the number 1. In the absence of an indication, the switch can be in either of these states, with the possibility that there may be a preferred state depending on the installation in question.

[0144] Thus, for this embodiment of a switching device 28 illustrated at Fig. 9A , the conduction configuration C_COND is achieved by bringing the isolation switch 48 and the cutoff switch 42.1, the latter being here formed by the primary switch 60.1 and the secondary switch 60.2, in their closed state. The pre-charge switch 58 For example, it can be in its open state. Preferably, the activation switch 72.1is in its open state and the configuration switch 78.1 is in its closed state.

[0145] In this embodiment, the cutoff configuration C_C involves bringing the pre-charge switch 58 in its open state, then the configuration switch 78.1 in its closed state. We saw earlier that the cutoff switch 42.1, namely, the primary switch 60.1 and the secondary switch 60.2, is brought to its open state, and the activation switch 72.1 is brought into its closed state so that the circuit for assisting the cut-off 70.1, which includes the pre-charge capability 54.1, so that it can perform its function of assisting with the disconnection. Preferably, for example, once the disconnection has been achieved, the isolation switch 48 is brought in its open state.

[0146] For this embodiment of a switching device28 illustrated at Fig. 9A , the insulation configuration C_ISOL is achieved by bringing the isolation switch 48, and the cutoff switch 42.1, namely, the primary interior 60.1 and the secondary switch 60.2, in their open state. At least one of the activation switches 72.1 and the configuration switch 78.1 is in its open state. For example, the pre-charge switch 58 is in its open state.

[0147] Loading configuration C_CH which aims to electrically charge the pre-charge capacity 54 of the pre-charge circuit 50 is achieved by bringing the isolation switch 48 and the pre-charge switch 58 in their closed state, the cut-off switch 42.1, namely, the primary interior 60.1 and the secondary switch 60.2,being brought to their open state just like the configuration switch 78.1 is also in its open state. Preferably, the activation switch 72.1 is also in its open state.

[0148] The pre-charge configuration C_PCH to allow the pre-charge capacitor to discharge 54.1 in the conductor of the downstream power line is obtained by bringing the isolation switch 48 in its open state, and by bringing the pre-charge switch 58 and the cutoff switch 42.1, namely, the primary interior 60.1 and the secondary switch 60.2, in their closed state. Preferably, to anticipate a possible need to reopen the shut-off device. 28, We can plan to bring in the configuration switch 78.1 in its closed state, but the activation switch 72.1 being then in its open state.

[0149] It is understood that, in order to ensure the pre-charge of the electrical conductor 21 of the downstream line which is electrically connected to the downstream point 38, this embodiment of the cutting device illustrated in the Fig. 9A is controlled in the manner described with reference to the Fig. 3 .

[0150] It is noted that it is possible to plan, before a first pre-charge stage of the electrical conductor 21, a preparation step during which all current flow is interrupted in the circuit providing assistance during the shutdown 70.1 between the stitching point 76 and the secondary point 46.1. This can be done, for example, by opening the activation switch. 72.1.

[0151] We illustrated on the Fig. 10A a variant embodiment of the switching device 28 of the Fig. 9A . The alternative implementation of the Fig. 10A is identical to that of the Fig. 9A , except for the presence of a bypass circuit 80 which extends, electrically parallel to the main circuit 34, between the first primary point 44.1 and a bypass point 82 arranged between the last secondary point, here the first secondary point 46.1 since this embodiment comprises only a single switching module 40.1, and the downstream point 38. A bypass switch is interposed in this bypass circuit. 84 which is in a closed state in the pre-charge configuration C_PCH and in an open state in the load configurations C_CH, insulation C_ISOL, cut-off C_C, and also in the conduction configuration C_COND. The bypass circuit 80 allows for the pre-charge configuration C_PCH, the pre-charge of the electrical conductor 21from the downstream power transmission line, through a circuit having the lowest possible parasitic inductance. The presence of the bypass circuit 80 allows you to move the configuration switch 78 to put it in the main line 34 between the first secondary point 46.1 and the bypass point 82. In this position within the disconnecting device, the configuration switch 78 is closed in the conduction configuration C_COND, and in the cutoff configuration C_C of the disconnecting device 28. In this position within the disconnecting device, the configuration switch 78 is open in the load configurations C_CH and preload C_PCH of the disconnecting device 28, to prevent the electrical conductor 21, connected to the downstream point 38,cannot discharge through the cut-off assistance circuit 70.1. This embodiment, which allows the configuration switch to be moved 78 outside the cut-off assistance circuit 70.1 allows for a circuit to assist in the event of a power outage 70.1 having the lowest possible parasitic inductance.

[0152] As can be seen on the Fig. 10B , The state of the other switches in the different configurations is the same as for the previous variant.

[0153] We illustrated on the Figs. 11A et 11B two variants of a disconnecting device according to the invention, which are derived from a disconnecting device architecture described in particular in documents WO-2016 / 003357 and WO-2017 / 116296, to which reference will be made in more detail for the operation of the disconnecting assistance circuit 70.1. In the switching devices 28 of the Figs. 11A et 11B , We therefore find a main circuit 34, in which a nominal direct current flows in a conduction configuration C_COND of the switching device, the main circuit 34 extending between an upstream point 36 intended to be electrically connected to a high-voltage direct current source 17 and a downstream point 38 intended to be electrically connected to a conductor 21 of a downstream power transmission line. These two embodiment variants here include a single switching module 40.1 including at least one disconnect switch 42.1 interposed in the main circuit 34 between a first primary point 44.1 and a first secondary point 46.1 of the main circuit 34. The first primary point 44.1 and the first secondary point 46.1 are located in that order in the main circuit 34between the upstream point 36 and the downstream point 38. Both of these embodiments include an isolation switch. 48, interposed in the main circuit 34 between the upstream point 36 and the first primary point 44.1. In this architecture, it is planned, in parallel with the switching module 40.1, a circuit to assist with the shutdown 70.1 which extends between the primary point 44.1 and the secondary point 46.1 which correspond to the considered switching module. In a switching configuration C_C, the cut-off assistance circuit 70.1 is designed to facilitate the extinguishing of an electric arc that may form between the terminals of the disconnect switch 42.1 during its opening. For this, the cut-off assistance circuit 70.1 includes, between the primary point 44.1 and the secondary point 46.1which correspond to the considered cutoff module, at least one dedicated inductive component 90.1, a controlled voltage source 92.1 and a capacitor 54.1. In this architecture, the circuit for assisting the disconnection 70.1 This forms an LC circuit in which current oscillations can be forced. The controlled voltage source 92.1 is controlled to create alternating currents of increasing intensity in the cut-off assistance circuit 70.1, until these current oscillations exceed in intensity the fault current in the disconnect switch 42.1. Thanks to such an oscillation, the circuit for assisting the cut-off 70.1 eventually injects into the main circuit 34,through the disconnect switch, a counter-current in the opposite direction to the fault current, and of a greater intensity than the fault current, causes the current in the disconnect switch to cross zero. 42.1, This leads to the extinction of the electric arc. It should also be noted that the cutting module 40.1 of the method of implementation of the Fig. 11A includes a surge protector 73.1 which is electrically arranged in parallel with the assembly including the capacitor 54.1, the controlled voltage source 92.1, and a configuration switch 78.1 which will be detailed later, to limit the voltage across this assembly. For its part, the cutoff module 40.1 of the method of implementation of the Fig. 11B includes a surge protector 75.1 which is electrically arranged in parallel with the capacitor 54.1 to limit the voltage across the capacitor 54.1.

[0154] Contrary to the basic architecture described in particular in documents WO-2016 / 003357 and WO-2017 / 116296, the disconnecting devices 28 of the Figs. 11A et 11B include a pre-charge circuit 50 which extends between the first primary point 44.1 and the earth 52 and which includes at least one pre-charge capacitor 54.1 at least one pre-charge resistor 56 and a pre-charge switch 58. As can be seen in the figures, in a cutoff configuration C_C, the shut-off device 28 is configured such that the pre-charge capacitor 54.1 of the pre-charge circuit 50 is part of the cut-off assistance circuit 70.1, in which it plays the role of the capacitor in the LC circuit designed to generate the oscillations.

[0155] The pre-charge circuit 50includes a first section, which is shared with the cut-off assistance circuit 70.1, which extends between the first primary point 44.1 and a stitching point 76 and which includes at least one pre-charge capacitor 54.1. The pre-charge circuit 50 includes a second section, separate from the cut-off assistance circuit 70.1, which extends between the stitching point 76 and the earth 52 and in which the pre-charge switch is interposed 58. Note that the pre-charge resistance 56 of the pre-charge circuit 50 In both variants, it is arranged in the second section of the pre-charge circuit. 50 which extends between the stitching point 76 and the earth 52, therefore outside the circuit of the cut-off assistance 70.1.

[0156] In the variant of the Fig. 11A , the controlled voltage source 92.1,which includes, for example, a controlled thyristor point and capacitors, is arranged in the part of the circuit that assists the interruption 70.1 which is common with the pre-charge circuit 50, here between at least one pre-charge capacitor 54.1 and the stitching point 76. In the variant of the Fig. 11B , the controlled voltage source 92.1, is arranged in the part of the circuit that assists in the shutdown 70.1 which is separate from the pre-charge circuit 50, here between the stitching point 76 and the secondary point 46.1.

[0157] Contrary to the basic architecture described in particular in documents WO-2016 / 003357 and WO-2017 / 116296, the disconnecting devices 28 of the Figs. 11A et 11B include a configuration switch 78.1 in the section of the circuit that assists the shutdown 70.1 which is separate from the pre-charge circuit50. The configuration switch 78.1 is arranged between the stitching point 76 and the downstream point 38. This configuration switch 78.1 is closed in a cutoff configuration C_C of the disconnecting device 28, during which the circuit for assistance with the cut-off 70.1 is active to interrupt the flow of current through the cutoff switch 42.1 Opening. This configuration switch 78.1 is open in the load configurations C_CH and preload C_PCH of the disconnecting device 28, to prevent the electrical conductor 21, connected to the downstream point 38, cannot discharge through the cut-off assistance circuit 70.1.

[0158] We illustrated at the Fig. 11C a painting that can be read in the same way as that of the Fig. 9B ,in which, for each of the configurations described above, a switching device has been represented 28 depending on one or the other of the variants of Figs. 11A et 11B , the state of the various switches in the configuration. In addition to the conduction configurations C_COND, insulation C_ISOL and cutting C_C, We therefore find a loading configuration C_CH in which the pre-charge switch 58 is in a closed state so that the pre-charge capacitor 54.1, the pre-charge resistance 56 and the pre-charge switch 58 are all electrically connected in series in the pre-charge circuit 50 between the first primary point 44.1 and the earth 52, while the first primary point 44.1 is electrically isolated from the downstream point 38 of the disconnecting device 28, in particular by opening the cut-off switch42.1, but electrically connected to the upstream point 36, by closing the isolation switch 48 to allow the pre-charge capacitor to be charged 54.1.On reverts to a pre-charge configuration C_PCH in which the pre-charge switch 58 is in its closed state so that the pre-charge capacitor 54.1, the pre-charge resistance 56 and the pre-charge switch 58 are all electrically connected in series in the pre-charge circuit 50 between the first primary point 44.1 and the earth 52, while the first primary point 44.1 is electrically isolated from the upstream point 36 of the disconnecting device, by opening the isolation switch 48, but electrically connected to the downstream point 38, by closing the cut-off switch 42.1 to allow the pre-charge capacitor to discharge54.1 in the driver 21 of the downstream power line.

[0159] We illustrated on the Fig. 12A a switching device according to the invention, which is derived from a switching device architecture described in particular in the document K. TAKATA et al. "HVDC Circuit Breakers for HVDC Grid Applications", CIGRE AORC 2014, to which reference should be made in more detail for the operation of the switching assistance device. In the switching device 28 of the Figs. 12A , We therefore find a main circuit 34, in which a nominal direct current flows in a conduction configuration of the switching device, the main circuit 34 extending between an upstream point 36 intended to be electrically connected to a high-voltage direct current source 17 and a downstream point 38 intended to be electrically connected to a conductor 21of a downstream power transmission line. This embodiment here comprises a single switching module 40.1 including at least one disconnect switch 42.1 interposed in the main circuit 34 between a first primary point 44.1 and a first secondary point 46.1 of the main circuit 34. The first primary point 44.1 and the first secondary point 46.1 are located in that order in the main circuit 34 between the upstream point 36 and the downstream point 38. This alternative embodiment includes an isolation switch 48, interposed in the main circuit 34 between the upstream point 36 and the first primary point 44.1. In this architecture, it is planned, in parallel with the switching module 40.1, a circuit to assist with the shutdown 70.1 which extends between the primary point 44.1and the secondary point 46.1 which correspond to the considered switching module. In a switching configuration C_C, the cut-off assistance circuit 70.1 is designed to facilitate the extinguishing of an electric arc that may form between the terminals of the disconnect switch 42.1 during its opening. For this, the cut-off assistance circuit 70.1 includes, between the primary point 44.1 and the secondary point 46.1 which correspond to the considered cutoff module, at least one dedicated inductive component 90.1, a capacitor 54.1 and an activation switch 72.1. In this architecture, the circuit for assisting the disconnection 70.1 This forms an LC circuit in which current oscillations can be forced, here by discharging the capacitor. 54.1. Indeed, starting with a capacitor 54.1When charged, closing the activation switch causes the capacitor to discharge in the cutoff assistance circuit. 70.1 which forms an LC circuit. This discharge occurs in the form of an oscillating current. As is known, this circuit assists in the interruption 70.1 The LC type is dimensioned, particularly in terms of capacitance and inductance, such that the current oscillations exceed the fault current in the disconnecting switch. 42.1. Thanks to such an oscillation, the circuit for assisting the cut-off 70.1 injects into the main circuit 34, through the cut-off switch 42.1, a counter-current in the opposite direction to the fault current, and with an intensity greater than the fault current, causing the current to cross zero in the disconnect switch 42.1,This leads to the extinction of the electric arc. It should also be noted that the switching module includes a surge protector. 75.1 which is electrically arranged in parallel with the capacitor 54.1 to limit the voltage across the capacitor 54.1.

[0160] Contrary to the basic architecture described in particular in the document K. TAKATA et al. "HVDC Circuit Breakers for HVDC Grid Applications", CIGRE AORC 2014, the circuit breaker 28 of the Fig. 12A includes a pre-charge circuit 50 which extends between the first primary point 44.1 and the earth 52 and which includes at least one pre-charge capacitor 54.1, at least one pre-charge resistor 56 and a pre-charge switch 58. As can be seen in the figure, in a cutoff configuration C_C, the shut-off device 28is configured such that the pre-charge capacitor 54.1 of the pre-charge circuit 50 is part of the cut-off assistance circuit 70.1, in which it plays the role of the capacitor in the LC circuit designed to generate the oscillations. In the example, the capacitor 54.1 The pre-charge capacitor is the only capacitor in the cut-off assistance circuit. 70.1, meaning that there is no capacitor in the section of the circuit that assists the disconnection 70.1 which is separate from the pre-charge circuit 50, here between the stitching point 76 and the secondary point 46.1. However, depending on the capacitance requirements for both the pre-charge operation and the cut-off assistance operation, it is possible to have, in addition to the pre-charge capacitor 54.1 which is arranged in the section of the pre-charge circuit 50which is common with the cut-off assistance circuit 70.1, at least one other capacitor, this other capacitor being arranged in the section of the circuit that assists the disconnection 70.1 which is separate from the pre-charge circuit 50, here between the stitching point 76 and the secondary point 46.1.

[0161] The pre-charge circuit 50 includes a first section, which is shared with the cut-off assistance circuit 70.1, which extends between the first primary point 44.1 and a stitching point 76 and which includes at least one pre-charge capacitor 54.1. The pre-charge circuit 50 includes a second section, separate from the cut-off assistance circuit 70.1, which extends between the stitching point 76 and the earth 52 and in which the pre-charge switch is interposed 58. Note that the pre-charge resistance56 of the pre-charge circuit 50 In this variant, it is arranged in the second section of the pre-charge circuit. 50 which extends between the stitching point 76 and the earth 52, therefore outside the circuit of the cut-off assistance 70.1.

[0162] In the implementation of the Fig. 12A , the dedicated inductive component 90.1 of the circuit assistance cut-off 70.1 is arranged in the part of the circuit that assists in the shutdown 70.1 which is separate from the pre-charge circuit 50, here between the stitching point 76 and the secondary point 46.1.

[0163] The activation switch 72.1 is arranged in the section of the cut-off assistance circuit 70.1 which is separate from the pre-charge circuit 50, here between the stitching point 76 and the secondary point 46.1.This activation switch 72.1 is in its closed state in a cutoff configuration C_C of the disconnecting device 28, during which the circuit for assistance with the cut-off 70.1 is active to interrupt the flow of current through the cutoff switch 42.1 Opening in progress. This activation switch 72.1 is open in the load configurations C_CH and preload C_PCH of the disconnecting device 28, to prevent the electrical conductor 21, connected to the downstream point 38, cannot discharge through the cut-off assistance circuit 70.1.

[0164] We illustrated at the Fig. 12B a painting that can be read in the same way as that of the Fig. 9B , in which, for each of the configurations described above, a switching device has been represented 28 according to the Fig. 12A ,the state of the various switches in the configuration. In addition to the conduction configurations C_COND, insulation C_ISOL and cutting C_C, We therefore find a loading configuration C_CH in which the pre-charge switch 58 is in a closed state, so the pre-charge capacitor 54.1, the pre-charge resistance 56 and the pre-charge switch 58 are all electrically connected in series in the pre-charge circuit 50 between the first primary point 44.1 and the earth 52, while the first primary point 44.1 is electrically isolated from the downstream point 38 of the disconnecting device 28, in particular by opening the cut-off switch 42.1, but electrically connected to the upstream point 36, by closing the isolation switch 48 to allow the pre-charge capacitor to be charged54.1. In this loading configuration C_CH, the activation switch 72.1 of the circuit assistance cut-off 70.1 is also open to isolate the tapping point 76 in relation to the first secondary point 46.1 and therefore in relation to the downstream point 38. A pre-charge configuration is also included. C_PCH in which the pre-charge switch 58 is in its closed state so that the pre-charge capacitor 54.1, the pre-charge resistance 56 and the pre-charge switch 58 are all electrically connected in series in the pre-charge circuit 50 between the first primary point 44.1 and the earth 52, while the first primary point 44.1 is electrically isolated from the upstream point 36 of the disconnecting device 28, by opening the isolation switch 48,but electrically connected to the downstream point 38, by closing the cut-off switch 42.1 to allow the pre-charge capacitor to discharge 54.1 in the driver 21 of the downstream power line. In this pre-charge configuration C_PCH, the activation switch 72.1 of the circuit assistance cut-off 70.1 is open to isolate the tapping point 76 in relation to the first secondary point 46.1 and therefore in relation to the downstream point 38.

[0165] It is noted that, in the method of implementation of the Fig. 12A , when the cut-off switch is opened 42.1 and the triggering of the cut-off assistance, the capacitor 54.1 which is shared by the cut-off assistance circuit 70.1 and by the pre-charge circuit 50 discharges. Thus, when the current has been interrupted, the capacitor 54.1can be discharged at a voltage different from that of the voltage source 17, or even lower than that of the voltage source 17. Also, in the context of a re-closing, it will be necessary, if one wants to perform a pre-charge step on the electrical conductor. 21, to first proceed with a step of recharging the capacitor 54.1 to recharge it, before being able to perform the first pre-charge step.

[0166] We illustrated on the Figs. 13A has 17A different embodiments of a switching device comprising several switching modules 40.1, 40.2, 40.3 which are successively interposed in the main circuit 34 between the first primary point 44.1 and the downstream point 38. In each of the embodiments of Figs. 13A has 17A , the shut-off device 28The described method can be used in place of those described previously, with the same possible configurations and the same possible control mode during re-closure as described above, to implement a process for evaluating the integrity of an electrical conductor with at least one conductor pre-charge step during which an auxiliary voltage source, separate from the main voltage source, is used. 17, is connected to the electrical conductor 21 to power it up while keeping it isolated from the main voltage source 17 and in relation to the rest of the electrical installation 10 as described above. These embodiments also allow for a pre-charge capacitor charging step during which the switching device is brought into the charging configuration C_CH.

[0167] It is understood that the multiplication of switching devices arranged successively in the main circuit 34 This allows the voltage across each of the breaking modules to be reduced at the moment of opening. This allows, either, for an increase in the breaking capacity of the breaking device. 28, given the performance of each module, that is, to obtain a given breaking capacity of the breaking device, to implement breaking modules having a significantly lower breaking capacity.

[0168] Thus, in each of these embodiments, the switching device 28 includes, downstream of the first cutoff module 40.1 in the main circuit 34 of the disconnecting device 28,at least one final disconnect module. A disconnect device comprising several disconnect modules could have only two disconnect modules, namely a first disconnect module and a final disconnect module interposed successively in the main circuit 34 between the first primary point 44.1 and the downstream point 38.

[0169] However, in the illustrated examples, the cutting device 28 includes more than two switching modules, namely, interposed successively in the main circuit 34 between the first primary point 44.1 and the downstream point 38, a first switching module, at least one additional switching module, and a final switching module. Thus, in the illustrated examples, the switching device 28 comprises three switching modules, namely, interposed successively in the main circuit 34 between the first primary point44.1 and the downstream point 38, a first cutoff module 40.1, a second cutoff module 40.2 forming an additional breaking module, and a third breaking module forming the final breaking module. A breaking device 28 According to the invention, it may comprise several additional switching modules interposed successively in the main circuit 34, between the first cutting module 40.1 and the last cutoff module 40.n.

[0170] The last cutoff module 40.3, Here, the third one includes at least one disconnect switch. 42.3, 60.3, 62.3 interposed in the main circuit 34 between a last primary point 44.3, downstream of the first secondary point 46.1, and one last secondary point 46.3 of the main circuit 34. Of course, the cut-off switch 42.3, 60.3, 62.3 of the last cutoff module 40.3is capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the last cutoff module 40.3.

[0171] Between the first cutoff module 40.1 and the last cutoff module 40.3 in the main circuit of the switching device 28, the additional disconnect module also includes at least one disconnect switch 42.2, 60.2, 62.2, interposed in the main circuit 34 between an additional primary point, here therefore the second primary point 44.2 downstream of the first secondary point 46.1, and an additional secondary point of the main circuit, in this case the second secondary point 46.2 upstream of the last primary point 44.3. Of course, the cut-off switch 42.2, 60.2, 62.2 of the additional module 40.2is capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the additional cutoff module.

[0172] In a switching device comprising several switching modules, there could be a pre-charge circuit which would be a dedicated circuit, as illustrated in the Fig. 3 , with a pre-charge circuit extending between the first primary point 44.1 and the earth and comprising at least one pre-charge capacitor, at least one pre-charge resistor and a pre-charge switch.

[0173] However, in the case where at least one of the disconnection modules includes a disconnection assistance circuit 70.1 implementing a capacitance, it is preferable to include at least one pre-charge capacitor in the pre-charge circuit. 50should also be part of the interruption assistance circuit of at least one of the interruption modules. If several, or even all, of the interruption modules each have an interruption assistance circuit implementing a capacitor, it is preferable that the pre-charge circuit 50 includes several pre-charge capacitors, and at least one pre-charge capacitor in the pre-charge circuit is also part of the cutoff assist circuit of a cutoff module, while at least one other pre-charge capacitor in the pre-charge circuit is part of the cutoff assist circuit of another cutoff module. For example, the pre-charge circuit 50includes several pre-charge capacitors, and each cutoff assistance circuit includes at least one pre-charge capacitor from the pre-charge circuit. In other words, at least one of the cutoff assistance circuits, preferably several, more preferably all of the cutoff assistance circuits, including at least one capacitor that has a function in the cutoff assistance, shares this at least one capacitor with the pre-charge circuit. 50.

[0174] In the illustrated examples, the last cutoff module 40.3, includes a circuit for shutting off 70.3 which extends electrically in parallel with the disconnect switch 42.3 of the last cutoff module 40.3 and the main circuit 34, between the last primary point 44.3 and the last secondary point 46.3 of the main circuit 34. In a cutoff configuration C_C, the shut-off device 28 is configured such that at least one pre-charge capacitor 54.3 the pre-charge circuit is part of the cut-off assistance circuit 70.3 of the last cutoff module 40.3. Similarly, in the illustrated examples, the additional cutoff module, for example the second additional cutoff module 40.2 includes a circuit for shutting off 70.2 which extends electrically in parallel with the disconnect switch 42.2 of the additional cutoff module 40.2 and the main circuit 34, between the primary point 44.2 and the secondary point 46.2 of the main circuit 34 which are associated with this switching module, here the second one 40.2. In a cutoff configuration C_C, the shut-off device 28 is configured such that at least one pre-charge capacitor 54.2the pre-charge circuit is part of the cut-off assistance circuit 70.2 of the additional cutoff module, for example the second cutoff module 40.2.

[0175] Preferably, in the cutoff configuration C_C of the disconnecting device, the disconnection assistance circuits of at least one upstream disconnecting module, for example the first disconnecting module 40.1, and a downstream cutoff module, for example the last cutoff module 40.3, are electrically connected in series. In some embodiments, this series connection is achieved by correctly configuring certain configuration switches. 78.1 and / or isolation 77.1 and / or even a shunt 79.1. In this context, we will see that, preferably, the circuit assisting the disconnection of the downstream disconnection module, for example the disconnection assistance circuit 70.3 of the last cutoff module 40.3,comprises, successively and in this order from the primary point of this downstream module, for example the last primary point 44.3, at least one pre-charge capacitor 54.3 and an activation switch 72.3, with a stitching point 76 between the two in this circuit for assisting the disconnection 70.3. Thus, the pre-charge circuit 50 includes a first segment that extends between the primary point of the upstream module, for example the first primary point 44.1, and the stitching point 76. This first section of the pre-charge circuit 50is common with the cut-off assist circuit, and includes at least one pre-charge capacitor for each of the cut-off assist circuits of modules whose assist circuits are in series, for example, those of the first and last cut-off modules. The pre-charge circuit has a second section, separate from the cut-off assist circuit, which extends between the tapping point 76 and the earth 52, and in which the pre-charge switch is interposed 58.

[0176] It is therefore understandable that, in a switching device 28 comprising several switching modules having a switching assistance circuit, it is sufficient that one of them has a tapping point from which branches off the second section of the pre-charge circuit, separate from the switching assistance circuit, which extends between the tapping point 76 and the earth 52,and in which the pre-charge switch is interposed 58. Indeed, in this case, it is sufficient that, in pre-charge configuration C_PCH and / or in loading configuration C_CH, The break-away assistance circuits of these modules, or at least the parts of these break-away assistance circuits including the capacitor of these circuits, are connected in series to form the first section of the pre-charge circuit. This first section of the pre-charge circuit, which therefore includes capacitors also belonging to the break-away assistance circuits, is connected at the tapping point. 76, with the second section of the pre-charge circuit, separate from the cut-off assistance circuit, which includes the pre-charge switch 58.

[0177] We will now detail how the general characteristics above are translated into the different embodiments that are illustrated.

[0178] In the following description, it will be assumed that, in each configuration of the switching device 28, all the cut-off modules 40.1, 40.2 And 40.3 which follow one another in the main circuit are in the same state at the same time, including with regard to the state of the cut-off assistance circuits of each of the cut-off modules.

[0179] In the implementation of the Fig. 13A , all the cut-off modules 40.1, 40.2 And 40.3 are identical and analogous to what has been described in relation to the method of implementation of the Fig. 9A . The different configurations of the cut-off device Fig. 13A are deduced from the different states of the switches which are indicated in the table of the Fig. 13B , which reads the same way as that of the Figure 9B .

[0180] In the implementation of the Fig. 13A ,shunt switches have been depicted 79.1, 79.2 which, for the usual conduction configurations C_COND, cut-off C_C, are in an open state. However, with the pre-charge switch 58 In its open state, we could have the shunt switches 79.1, 79.2 in their closed state for these configurations.

[0181] We have also represented for each cutting module 40.i, a configuration switch 78.i (here 78.1, 78.2, 78.3) in the cut-off assistance circuit 70.i, between the activation switch 72.i of the considered cutoff module and the secondary point 46.i of the module in question. In each switching module 40.i, this configuration switch 78.i therefore has the same location as its counterpart in the embodiment of the fig. 9A .

[0182] We also represented that the last module 70.3,and each additional cutoff module, so here the second cutoff module 70.2, include an isolation switch 77.2, 77.3 in the circuit for assisting the disconnection considered, between the primary point 44.2, 44.3 of the considered cutoff module and respectively the capacitor 54.2, 54.3 of the circuit assisting the disconnection of the considered disconnection module. Thus, the isolation switch 77.2, 77.3 and the configuration switch 78.2, 78.3 of a given switching module delimit between themselves a segment of the switching assistance circuit which includes the following elements of this switching assistance circuit: the capacitor 54.2, 54.3, the activation switch 72.2, 72.3 and the possible tertiary surge protector 74.2, 74.3 which can be arranged at the terminals of the activation switch 72.2, 72.3. In the cutoff configuration C_C, the isolation switch 77.2, 77.3 and the configuration switch 78.1of a given switching module are in their closed state, so that the elements within the segment can perform their role in assisting the switching. It should also be noted that, in the switching configuration C_C, the circuit breakers assisting with the disconnection of at least the first disconnection module 40.1 and the last cutoff module 40.3, but preferably also those of the additional cut-off module(s). 40.2 are electrically arranged in series. For example, in the switching configuration C_C of the disconnecting device 28, the cut-off assistance circuit 70.2 of the additional cutoff module 40.2 is electrically arranged in series between and with the circuit breakers 70.1, 70.3 of the first and last cut-off modules 40.1, 40.3.

[0183] However, in the cutoff configuration C_C, each circuit for assisting the disconnection, at least of the first disconnection module 40.1 and the last cutoff module 40.3, but preferably also the one(s) of the additional cutoff module(s) 40.2 remains, considered individually, arranged in parallel with the disconnect switch 42.i of the cutoff module to which it belongs.

[0184] In the loading configurations C_CH and preload C_PCH, the isolation switch 77.2, 77.3 and the configuration switch 78.1, 78.2, 78.3 of a given switching module are in their open state, to isolate the elements included in the segment from the main line 34. Furthermore, in the loading configurations C_CH and preload C_PCH, the activation switch 72.i is open and the shunt switches 79.1, 79.2are closed. This combination reveals that, in the loading configurations C_CH and preload C_PCH, capacitors 54.1, 54.2 And 54.3 which, in the cutoff configuration C_C, are located in the cut-off assistance circuit, and are then arranged directly in series with each other in the pre-charge circuit 50, between the first primary point 44.1 and the earth. In this embodiment, and with this combination, only the capacitors 54.i The circuit breakers are connected in series within the pre-charge circuit. This series arrangement increases the voltage rating of the capacitors in the pre-charge circuit. 50, which, in the cutoff configuration C_C, are each associated with a switching module. The presence of shunt switches 79.1, 79.2,in their closed state, allows for the following loading configurations C_CH and preload C_PCH, the most direct possible path of the current in the pre-charge circuit 50.

[0185] On the other hand, it is understood that in this method of implementation of the Fig. 13A , for pre-charge configuration C_PCH, the current generated by the discharge of the capacitors must pass through all the cutoff switches which are in their closed state.

[0186] Also, it was illustrated on the Fig. 14A an embodiment in which all the switching modules 40.1, 40.2 et 40.3 are identical to each other, and are analogous to what has been described in relation to the method of implementation of the Fig. 10A , The different configurations of the cut-off device Fig. 14A are deduced from the different states of the switches which are indicated in the table of the Fig. 14B ,which reads the same way as that of the Figure 10B .

[0187] The shut-off device 28 includes, interposed successively in the main circuit 34 between the first primary point 44.1 and the downstream point 38, a first cutoff module 40.1, an additional cutoff module 40.2, also called here the second cutoff module 40.2, and a final cutoff module 40.3. Each cutting module 40.i includes a cut-off switch 42.i, here implemented in the form of two successive switches 60.i, 62.i interposed in the main circuit 34 between a primary point 44.i and a secondary point 46.i of the main circuit 34 which are associated with the cutoff module 40.i.It is understood that each module is arranged in such a way that the primary point of an additional module or the last module is directly connected, and preferably electrically identical, with the secondary point of the module preceding it in the upstream-downstream direction in the main circuit. 34.

[0188] Each cutting module 40.i includes a circuit for shutting off 70.i implementing a capacity, and we will see that the switching device 28 includes a pre-charge circuit 50 having at least as many pre-charge capacitors 54.i that the number of modules, and that each circuit assists with the disconnection 70.i includes at least one pre-charge capacitor 54.i of the pre-charge circuit.

[0189] In the cutoff configuration C_C of the disconnecting device, the disconnection assistance circuits 70.iare electrically arranged in series between the first primary point 44.1 and the last secondary point 46.3. This stems from the fact that each module is arranged in such a way that the primary point of an additional module or the last module is directly connected, and preferably electrically coincident, with the secondary point of the module preceding it in the upstream-downstream direction in the main circuit. 34, and that the cut-off assistance circuit 70.i from each disconnect module extends electrically in parallel with the disconnect switch 42.i of the cutoff module 40.i and the main circuit 34, between the primary point 44.i and the secondary point 46.i of the main circuit 34 which are associated with this module.

[0190] Each circuit for assistance with the shutdown 70.iincludes at least one capacitor, which is advantageously a pre-charge capacitor. 54.i in the sense that it also belongs to the pre-charge circuit 50, and an activation switch 72.i.

[0191] The cut-off assistance circuit 70.3 of the last cutoff module 40.3 comprises, successively and in this order from the last primary point 44.3, at least one pre-charge capacitor 54.3 and an activation switch 72.3, with a stitching point 76 between the two in this last circuit to assist the cut-off 70.3.

[0192] The pre-charge circuit 50 includes a first segment that extends between the first primary point 44.1 and the stitching point 76,which is common to the series of break-assist circuits, and which includes at least one pre-charge capacitor for each of the break-assist circuits of each of the break modules. The pre-charge circuit 50 includes a second section, separate from the various circuit breakers, which extends between the tapping point 76 and the earth 52 and in which the pre-charge switch is interposed 58.

[0193] In this embodiment, the disconnection modules do not need to incorporate a configuration switch in each reference disconnection assistance circuit as was envisaged in the embodiment of the Fig. 10A .

[0194] We illustrated on the Fig. 14A the presence of a bypass circuit 80 which extends, electrically parallel to the main circuit 34 between the first primary point44.1 and a bypass point 82 arranged between the last secondary point 46.3 and the downstream point 38. In this bypass circuit 80 a bypass switch is interposed 84 which is in a closed state in the pre-charge configuration C_PCH and in an open state in the load configurations C_CH, insulation C_ISOL, cut-off C_C, and also in the conduction configuration C_COND. The bypass circuit 80 allows for the pre-charge configuration C_PCH, the pre-charge of the electrical conductor 21 of the downstream power transmission line, while maintaining circuit breakers 70.i with the lowest possible parasitic inductance. The presence of the bypass circuit 80 allows you to move the configuration switch 78 to put it in the main line 34between the last secondary point 46.3 and the bypass point 82. The configuration switch 78 is closed in the conduction configuration C_COND, and in the cutoff configuration C_C of the disconnecting device 28. The configuration switch 78 is open in the load configurations C_CH and preload C_PCH of the disconnecting device 28, to prevent the electrical conductor 21, connected to the downstream point 38, cannot discharge, in particular through the cut-off assistance circuit 70.3. Preferably, the configuration switch 78 is open in the insulation configuration C_ISOL.

[0195] In the switching device 28 of the Fig. 14A , Only one switching module, the last one, has a tapping point. 76from which the second section of the pre-charge circuit is detached. In pre-charge configuration C_PCH and / or in loading configuration C_CH, The entirety of each assistance circuit of the cut-off modules is connected in series to form the first section of the pre-charge circuit.

[0196] It is noted that it is possible to plan, before a first pre-charge stage of the electrical conductor 21, a preparation step during which all current flow is cut off in the circuit breakers 70.i between the stitching point 76 and the last secondary point 46.3. This can be done, for example, by opening the configuration switch. 78.

[0197] We illustrated on the Fig. 15A an embodiment in which all the switching modules 40.1, 40.2 And 40.3are identical to each other, and are analogous to what has been described in relation to the method of implementation of the Fig. 11A , The only difference is that the configuration switch is no longer in the disconnect modules, as just described with reference to the Fig. 14A .

[0198] The shut-off device 28 includes, interposed successively in the main circuit 34 between the first primary point 44.1 and the downstream point 38, a first cutoff module 40.1, an additional cutoff module 40.2, also called here the second cutoff module 40.2, and a final cutoff module 40.3. Each cutting module 40.i includes a cut-off switch 42.i interposed in the main circuit 34 between a primary point 44.i and a secondary point 46.i of the main circuit 34which are associated with the cutoff module 40.i. We understand that each cutting module 40.i is arranged such that the primary point of an additional switching module or the last switching module is directly connected, and preferably electrically identical, with the secondary point of the module preceding it in the upstream-downstream direction in the main circuit 34.

[0199] Each cutting module 40.i includes a circuit for shutting off 70.i implementing a capacitance, an inductance 90.i and a controlled voltage source 92.i. The shut-off device 28 includes a pre-charge circuit 50 having at least as many pre-charge capacitors 54.i the number of modules, and each circuit for assistance with the disconnection 70.i includes at least one pre-charge capacitor 54.i of the pre-charge circuit.

[0200] In the implementation of the Fig. 15A , shunt switches have been depicted 79.1, 79.2 which, for the usual conduction configurations C_COND, cut-off C_C and insulation C_ISOL, are in an open state. Thus, in the cutoff configuration C_C of the disconnecting device, the disconnection assistance circuits 70.i are electrically arranged in series, successively between the first primary point 44.1 and the last secondary point 46.3.

[0201] The cut-off assistance circuit 70.3 of the last cutoff module 40.3 comprises, successively and in this order from the last primary point 44.3, at least one pre-charge capacitor 54.3 and a controlled voltage source 92.3, with a stitching point 76 between the two in this last circuit to assist the cut-off 70.3.

[0202] The pre-charge circuit 50 includes a first segment that extends between the first primary point 44.1 and the stitching point 76, which is common to the series of break-assist circuits, and which includes at least one pre-charge capacitor for each of the break-assist circuits of each of the break modules. The pre-charge circuit 50 includes a second section, separate from the various circuit breakers, which extends between the tapping point 76 and the earth 52 and in which the pre-charge switch is interposed 58. In the example, the pre-charge resistance 56 is also in this second section which is distinct from the different circuit assistance systems for the cut-off.

[0203] It can advantageously be predicted that, in the loading configurations C_CH and preload C_PCH, shunt switches79.1, 79.2 are closed. Thus, the capacitors 54.1, 54.2 And 54.3 which, in the cutoff configuration C_C, are found in the cut-off assistance circuit, are found in the loading configurations C_CH and preload C_PCH, arranged directly in series with each other in the pre-charge circuit 50, between the first primary point 44.1 and the earth 52. More specifically, in pre-charge configuration C_PCH and / or in loading configuration C_CH, only a portion of each circuit assisting the cutoff modules, comprising at least one capacitor 54.1 The capacity of each circuit's cutoff assistance is connected in series to form the first section of the pre-charge circuit. This series arrangement increases the voltage rating of the capacitor assembly in the pre-charge circuit. 50,which, in the cutoff configuration C_C, Each is associated with a switching module. The presence of shunt switches 79.1, 79.2, in their closed state, allows for the following loading configurations C_CH and preload C_PCH, the most direct possible path of the current in the pre-charge circuit. In particular, it is noted that the pre-charge circuit thus formed with the shunt switches 79.1, 79.2, in their closed state avoid inductances 90.2 And 90.3 at least some of the circuit breakers 70.2, 70.3.

[0204] In this embodiment, the switching modules 40.i do not need to incorporate a configuration switch in each disconnection assistance circuit. Indeed, this has been illustrated on the Fig. 15A the presence of a bypass circuit 80 identical to that of the method of implementation of the Fig. 14A .The bypass circuit 80 extends in parallel electrically with the main circuit 34 between the first primary point 44.1 and a bypass point 82 arranged between the last secondary point 46.3 and the downstream point 38. In this bypass circuit 80 a bypass switch is interposed 84 which is in a closed state in the pre-charge configuration C_PCH and in an open state in the load configurations C_CH, insulation C_ISOL, cut-off C_C, and also in the conduction configuration C_COND. The bypass circuit 80 allows for the pre-charge configuration C_PCH, the pre-charge of the electrical conductor 21 of the downstream power transmission line, while maintaining circuit breakers 70.i with the lowest possible inductance. The presence of the bypass circuit 80allows you to move the configuration switch 78 to put it in the main line 34 between the last secondary point 46.3 and the bypass point 82. The configuration switch 78 is closed in the conduction configuration C_COND, and in the cutoff configuration C_C of the disconnecting device 28. The configuration switch 78 is open in the load configurations C_CH and preload C_PCH of the disconnecting device 28, to prevent the electrical conductor 21, connected to the downstream point 38, cannot discharge, in particular through the cut-off assistance circuit 70.3. Preferably, the configuration switch 78 is open in the insulation configuration C_ISOL.

[0205] The different configurations of the cut-off device Fig. 15A are deduced from the different states of the switches which are indicated in the table of the Fig. 15B , which reads the same way as that of the Figure 9B .

[0206] We illustrated on the Fig. 16A an embodiment comprising several successive switching modules in the main circuit, all the switching modules 40.1, 40.2 et 40.3 being identical to each other, and being analogous to what has been described in relation to the method of implementation of the Fig. 11B , but the switching modules being assembled in a manner analogous to what has been described in relation to the Fig. 13A . Thus, in the cutoff configuration C_C of the disconnecting device 28 of the Fig. 16A , all the circuit breakers 70.i are electrically arranged in series by correctly configuring certain configuration switches 78.i, isolation77.i and shunt 79.i.

[0207] We have thus represented for each cutoff module 40.i, a configuration switch 78.i (here 78.1, 78.2, 78.3) in the cut-off assistance circuit 70.i, between the controlled voltage source 92 i of the considered cutoff module and the secondary point 46.i of the module in question. In each switching module 40.i, this configuration switch 78.i therefore has the same location as its counterpart in the embodiment of the fig. 11B .

[0208] We also find, for the last module 70.3, and for each additional cutoff module, so here for the second cutoff module 70.2, an isolation switch 77.2, 77.3 in the circuit for assisting the disconnection considered, between the primary point 44.2, 44.3 of the considered cutoff module and respectively the capacitor 54.2, 54.3of the circuit assisting the disconnection of the considered disconnection module. Thus, the isolation switch 77.2, 77.3 and the configuration switch 78.2, 78.3 of a given switching module delimit between themselves a segment of the switching assistance circuit which includes the following elements of this switching assistance circuit: the capacitor 54.2, 54.3, the controlled tension race 92 i and the possible surge protector 75.2, 75.3 which can be arranged across the terminals of the capacitor 54.2, 54.3. In the cutoff configuration C_C, the isolation switch 77.2, 77.3 and the configuration switch 78.i of a considered switching module are in their closed state, so that the elements included in the segment can play their role in assisting the switching.

[0209] In this implementation of the Fig. 16A , shunt switches have been depicted 79.1, 79.2which, for the usual conduction configurations C_COND, cut-off C_C and insulation C_ISOL, are in an open state and arranged in such a way that, in the cutoff configuration C_C of the disconnecting device, the disconnection assistance circuits 70.i are, in their entirety, electrically arranged in series, successively between the first primary point 44.1 and the last secondary point 46.3. while remaining, considered individually, arranged in parallel with the disconnect switch 42.i of the cutoff module to which they belong.

[0210] The cut-off assistance circuit 70.3 of the last cutoff module 40.3 comprises, successively and in this order from the last primary point 44.3, at least one pre-charge capacitor 54.3, a controlled voltage source 92.3, and a configuration switch 78.3,with a stitching point 76 between the two in this last circuit to assist the cut-off 70.3.

[0211] In the loading configurations C_CH and preload C_PCH, the isolation switch n 77.2, 77.3 and the configuration switch 78.1, 78.2, 78.3 of a given switching module are in their open state, to isolate the elements included in the segment from the main line 34. Furthermore, in the loading configurations C_CH and preload C_PCH, shunt switches 79.1, 79.2 are closed. Thus, the capacitors 54.1, 54.2 And 54.3 which, in the cutoff configuration C_C, each are located in a circuit for assistance with the shutdown 70.i, are found in the loading configurations C_CH and preload C_PCH, arranged in series in the pre-charge circuit 50, between the first primary point44.1 and the earth 52. The presence of the shunt switches, in their closed state, allows for the following loading configurations C_CH and preload C_PCH, a more direct path of the current in the pre-charge circuit, avoiding inductances 90.2 And 90.3 of the second and last switching modules.

[0212] In loading configuration C_CH and preload C_PCH, the pre-charge circuit 50 includes a first segment that extends between the first primary point 44.1 and the stitching point 76, which includes at least one pre-charge capacitor for each of the break-assist circuits of each of the break modules. In this embodiment of the Fig. 16A , we can see that, in the loading configurations C_CH and preload C_PCH, the first section of the pre-charge circuit 50also includes the controlled voltage source 92.1 of each of the circuit assistance systems for the interruption of each of the interruption modules. In doing so, the pre-charge step of conductor 21 can be used to also charge capacitors in the controlled voltage source, which is then operational for a subsequent interruption step.

[0213] The pre-charge circuit 50 includes a second section, separate from the various circuit breakers, which extends between the tapping point 76 and the earth 52 and in which the pre-charge switch is interposed 58. In the example, the pre-charge resistance 56 is also in this second section which is distinct from the different circuit assistance systems for the cut-off.

[0214] The different configurations of the cut-off device Fig. 16A are deduced from the different states of the switches which are indicated in the table of the Fig. 16B , which reads the same way as that of the Figure 9B .

[0215] We illustrated on the Fig. 17A an embodiment comprising several successive switching modules in the main circuit, all the switching modules 40.1, 40.2 et 40.3 being identical to each other, and being analogous to what has been described in relation to the method of implementation of the Fig. 12A , but the switching modules being assembled in a manner analogous to what has been described in relation to the Fig. 14A .

[0216] The shut-off device 28 includes, interposed successively in the main circuit 34 between the first primary point 44.1 and the downstream point 38, a first cutoff module 40.1, an additional cutoff module 40.2,also called here the second cutoff module 40.2, and a final cutoff module 40.3. Each cutting module 40.i includes a cut-off switch 42.i, interposed in the main circuit 34 between a primary point 44.i and a secondary point 46.i of the main circuit 34 which are associated with the cutoff module 40.i. It is understood that each module is arranged in such a way that the primary point of an additional module or the last module is directly connected, and preferably electrically identical, with the secondary point of the module preceding it in the upstream-downstream direction in the main circuit. 34.

[0217] Each cutting module 40.i includes a circuit for shutting off 70.1 implementing a capacity 54.i and an inductance 90.i, and we will see that the cutting device 28 includes a pre-charge circuit50 having at least as many pre-charge capacitors 54.i that the number of modules, and that each circuit assists with the disconnection 70.i includes at least one pre-charge capacitor 54.i of the pre-charge circuit.

[0218] As in the implementation method of the Fig. 14A , the circuit breakers are, in the break configuration C_C of the switching device, electrically arranged in series, in their entirety, between the first primary point 44.1 and the last secondary point 46.3. Each assistance circuit includes at least one pre-charge capacitor 54.i, which we can see is advantageously a pre-charge capacitor, and in this sense, it also belongs to the pre-charge circuit 50, and an activation switch 72.i. In the illustrated example, each assistance circuit includes an inductance 90.ibetween the activation switch 72.i and the secondary point of the cutoff module 40.i considered.

[0219] The cut-off assistance circuit 70.3 of the last cutoff module 40.3 comprises, successively and in this order from the last primary point 44.3, at least one pre-charge capacitor 54.3 and an activation switch 72.3, with a stitching point 76 between the two in this last circuit to assist the cut-off 70.3.

[0220] The pre-charge circuit 50 includes a first segment that extends between the first primary point 44.1 and the stitching point 41, which is common to the series of break-assist circuits, and which includes at least one pre-charge capacitor for each of the break-assist circuits of each of the break modules. The pre-charge circuit 50includes a second section, separate from the various circuit breakers, which extends between the tapping point 76 and the earth 52 and in which the pre-charge switch is interposed 58.

[0221] In this embodiment, the disconnection modules do not need to incorporate a configuration switch in each reference disconnection assistance circuit as was envisaged in the embodiment of the Fig. 10A . Indeed, the presence of a bypass circuit has been illustrated. 80, and a configuration switch 78 in the main line 34, For a description of which, please refer to the passage above with reference to the Fig. 14A .

[0222] Depending on the embodiments, it may be foreseen that, after the complete closure of the power cut-off device 28By switching the current-interrupting device to a conductive state, the discharge of the pre-charge capacitor(s) is triggered. This can be implemented, for example, in the context of the embodiments of figures 9A , 10A , 13A et 14A where the pre-charge capacitor must be discharged to perform its role in the cut-off assistance function.

[0223] In the embodiments described above with reference to figures 9A and following, each of the switching modules of the embodiment considered includes a capacitor that is used in the pre-charging process of the electrical conductor of the power transmission line by being inserted, at least for the charging and pre-charging configurations, into the pre-charging circuit. However, the invention also covers the case of a switching device which, in addition to a switching module having a capacitor that is thus used, may include one or more additional switches in the main circuit 34 between the first primary point 44.1 and the downstream point 38,that are not associated with a capacitor. Such switches may, for example, not include break-assistance circuits. Similarly, the invention also covers the case of a breaking device which, in addition to a breaking module having a capacitor that is thus utilized, may include one or more complementary switches in the main circuit. 34 between the first primary point 44.1 and the downstream point 38, which are associated with a capacitance, for example a capacitor, but whose capacitance is not inserted into the pre-charge circuit for the charge and pre-charge configurations. In both cases, such switches will preferably be controlled between their open and closed states, for each of the respective embodiments, in the same way as the break switches as described with reference to the figures 9Aand following. It is noted that one or more such switches can be found in the main circuit. 34 between the first primary point 44.1 and the downstream point 38, upstream of the first cutoff module 44.1, downstream of the last cutoff module 44.3, or between the first cutoff module 44.1 and the last cutoff module 44.3. Thus, within the scope of the invention, the last cutoff module should be interpreted as the last cutoff module associated with a capacitor that is inserted into the pre-charge circuit for the charging and pre-charging configurations. Similarly, within the scope of the invention, the first cutoff module should be interpreted as the first cutoff module associated with a capacitor that is inserted into the pre-charge circuit for the charging and pre-charging configurations.

[0224] In general, each of the embodiments described above allows for the implementation of a control method to ensure the re-closing of the switching device through which the overhead line is powered before being reconnected to the high-voltage direct current network. This is achieved using the internal energy of the capacitor integrated into a switching device, particularly a mechanical one, without directly connecting the line electrically to the high-voltage direct current source. 17, in order to limit the disturbances induced in the HVCD network unit 12, and more generally, in order to limit the disturbances imposed on the high-voltage direct current source 17. The line is pre-charged using an auxiliary circuit, referred to above as the pre-charge circuit. This solution allows for multiple retries thanks to controlled capacitor charging and enables the pre-charging of very long transmission lines.

Claims

1. A breaking device (28) for high DC voltage electric current including: - a main circuit (34), wherein a nominal direct current flows in a conduction configuration (C_COND) of the breaking device, the main circuit extending between an upstream point (36) intended to be electrically connected to a high DC voltage source (17) and a downstream point (38) intended to be electrically connected to a conductor (21) of a downstream electrical line; - at least one first breaking module (40.1) comprising at least one breaking switch (42.1) interposed in the main circuit between a first primary point (44.1) and a first secondary point (46.1) of the main circuit, the first primary point and the first secondary point being located in this order in the main circuit between the upstream point and the downstream point, and the breaking switch being capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the first breaking module, - an isolation switch (48), interposed in the main circuit between the upstream point and the first primary point, the isolation switch being capable of being controlled between an open state and a closed state; the breaking device (28) including a pre-charge circuit (50), which extends between the first primary point (44.1) and the ground (52) and which includes at least one pre-charge capacitor (54, 54.1), at least one pre-charge resistor (56), characterized in that the pre-charge circuit includes a pre-charge switch (58), in that the breaking device has at least: - a charging configuration (C_CH) wherein the pre-charge switch (58) is in a closed state so that the pre-charge capacitor (54, 54.1), the pre-charge resistor (56), and the pre-charge switch (58) are all electrically in series in the pre-charge circuit (50) between the first primary point (44.1) and the ground, while the first primary point (44.1) is electrically isolated from the downstream point (38) of the breaking device but electrically connected to the upstream point (36) to allow the charging of the pre-charge capacitor; - a pre-charge configuration (C_PCH) wherein the pre-charge switch (58) is in its closed state so that the pre-charge capacitor (54, 54.1), the pre-charge resistor (56), and the pre-charge switch (58) are all electrically in series in the pre-charge circuit (50) between the first primary point (44.1) and the ground (52), while the first primary point (44.1) is electrically isolated from the upstream point (36) of the breaking device (28) but electrically connected to the downstream point (38) to allow a discharge of the pre-charge capacitor (54, 54.1) into the conductor (21) of the downstream electrical line; - an isolation configuration (C_ISOL) wherein the first primary point (44.1) is isolated from the upstream point (36), with the isolation switch (48) in its open state, and is isolated from the downstream point (38), with the breaking switch (42.1) in its open state, and in that, in the conduction configuration (C_COND), the pre-charge switch (58) is open to isolate the first primary point (44.1) with respect to the ground, and the upstream point (36) is electrically connected to the downstream point by the main circuit (34) comprising the breaking switch (42.1) and the isolation switch (48) both in their closed state.

2. The current breaking device according to claim 1, characterized in that the first breaking module (40.1) includes a breaking assistance circuit (70.1), which extends electrically in parallel with the breaking switch (42.1) and the main circuit (34) between the first primary point (44.1) and the first secondary point (46.1) of the main circuit (34), and in that, in a breaking configuration (C_C), the breaking device (28) is configured such that at least one pre-charge capacitor (54.1) of the pre-charge circuit (50) is part of the breaking assistance circuit (70.1) of the first breaking module (40.1).

3. The current breaking device according to any one of claims 1 or 2, characterized in that it comprises, downstream of the first breaking module (40.1) in the main circuit (34) of the breaking device (28), at least one last breaking module (40.n) comprising at least one breaking switch (42.n) interposed in the main circuit (34) between a last primary point (44.n), downstream of the first secondary point (46.1), and a last secondary point (46.n) of the main circuit, and the breaking switch (42.n) of the last breaking module (40.n) being capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the last breaking module (40.n).

4. The current breaking device according to claim 3, characterized in that the last breaking module (40.n) includes a breaking assistance circuit (70.n), which extends electrically in parallel with the breaking switch (42.n) of the last breaking module (40.n) and the main circuit, between the last primary point (44.n) and the last secondary point (46.n) of the main circuit, and in that, in a breaking configuration (C_C), the breaking device (28) is configured such that at least one pre-charge capacitor (54.n) of the pre-charge circuit (50) is part of the breaking assistance circuit (70.n) of the last breaking module (40.n).

5. The current breaking device according to claim 4, characterized in that the pre-charge circuit (50) comprises at least one first pre-charge capacitor (54.1) and at least one second pre-charge capacitor (54.n), and in that, in a breaking configuration (C_C), the breaking device is configured such that the first pre-charge capacitor (54.1) is part of the breaking assistance circuit (70.1) of the first breaking module while the second pre-charge capacitor (54.n) is part of the breaking assistance circuit (70.n) of the last breaking module (40.n).

6. The current breaking device according to any one of claims 3 to 5, characterized in that it comprises, in the main circuit (34) of the breaking device (28), between the first breaking module (40.1) and the last breaking module (40.3), at least one additional breaking module (40.2) comprising at least one breaking switch (42.2) interposed in the main circuit between an additional primary point (44.2), downstream of the first secondary point (46.1), and an additional secondary point (46.2) of the main circuit, upstream of the last primary point (44.3), and the breaking switch (42.2) of the additional breaking module (40.2) being capable of being controlled between an open state and a closed state to determine respectively an open state and a closed state of the additional breaking module (40.2).

7. The current breaking device according to claim 6, characterized in that an additional breaking module (40.2) includes a breaking assistance circuit (70.2), which extends electrically in parallel with the breaking switch (42.2) of the additional breaking module (40.2) considered and the main circuit (34) between the additional primary (44.2) and secondary (46.2) points of the main circuit, which correspond to the additional breaking module (40.2) considered, and in that, in a breaking configuration (C_C), the breaking device (28) is configured such that at least one pre-charge capacitor (54.2) of the pre-charge circuit (50) is part of the breaking assistance circuit (70.2) of the additional breaking module (40.2).

8. The current breaking device according to claim 2, characterized in that the breaking device includes a single breaking module (40.1) whose breaking assistance circuit (70.1) includes, successively and in this order from the first primary point (44.1), the at least one pre-charge capacitor (54.1) and an activation switch (72.1), with a tapping point (76) between the two in the breaking assistance circuit (70.1), in that the pre-charge circuit (50) includes a first section, which is common with the breaking assistance circuit (70.1), which extends between the first primary point (44.1) and the tapping point (76) and which comprises the at least one pre-charge capacitor (54.1), and in that the pre-charge circuit (50) includes a second section, distinct from the breaking assistance circuit (70.1), which extends between the tapping point (76) and the ground (52) and wherein the pre-charge switch (58) is interposed.

9. The current breaking device according to any one of claims 1 to 7 taken in combination with claims 2 and 4, characterized in that the breaking device includes at least one upstream breaking module (40.1) and a downstream breaking module (40.3) whose breaking assistance circuits (70.1, 70.3) are, in the breaking configuration (C_C) of the breaking device (28), electrically arranged in series, in that the breaking assistance circuit (70.3) of the downstream breaking module (40.3) includes, successively and in this order from the downstream primary point (44.3), the at least one pre-charge capacitor (54.3) and an activation switch (72.3), with a tapping point between the two in the breaking assistance circuit, in that the pre-charge circuit includes a first section, which extends between the upstream primary point (44.1) and the tapping point (76), which is common with the breaking assistance circuits in series, and which comprises the at least one pre-charge capacitor (54.1, 54.3) of each of the breaking assistance circuits in series, and in that the pre-charge circuit (50) includes a second section, distinct from the breaking assistance circuits, which extends between the tapping point (76) and the ground (52) and wherein the pre-charge switch (58) is interposed.

10. The current breaking device according to any one of the preceding claims, characterized in that it comprises a bypass circuit (80) which extends, electrically in parallel with the main circuit (34), between the first primary point (44.1) and a bypass point (82) arranged between the last secondary point (46.1, 46.n) and the downstream point (38), and wherein a bypass switch (84) is interposed, which is in a closed state in the pre-charge configuration (C_PCH) and in an open state in the charging (C_CH), isolation (C_ISOL) and breaking (C_C) configurations.

11. The current breaking device according to claim 10, characterized in that it comprises a configuration switch (78), which is arranged in the main circuit (34) between the last secondary point (46.1, 46.3) and the bypass point (82), and which is in an open state in the pre-charge (C_PCH) and charging (C_CH) configurations, and in a closed state in the conduction (C_COND) and breaking (C_C) configurations.

12. The current breaking device according to any one of claims 1 to 11 taken in combination with claims 2 and 4, characterized in that it comprises at least one shunt switch (79.1, 79.2) which, in the charging (C_CH) and pre-charge (C_PCH) configurations, is in a closed state to connect in series, in the pre-charge circuit (50), the pre-charge capacitors (54.i) belonging to the different breaking modules (40.i).

13. An electrical installation (10) including a high-voltage DC source (17) electrically connected to at least one overhead conductor (21) of a downstream power line comprising an overhead line, characterized in that it includes, interposed between the high-voltage DC source (17) and the overhead conductor of the downstream power line comprising an overhead line, a current breaking device (28) according to any of the preceding claims, the high-voltage DC source (17) being connected to the upstream point (36) of the breaking device (28), and the overhead conductor (21) being electrically connected by an upstream end to the downstream point (38) of the breaking device (28).

14. A closing control method of a current breaking device according to any one of claims 1 to 12, the breaking device (28) being initially in the isolation configuration (C_ISOL), characterized in that it includes at least one pre-charge step of the conductor during which the breaking device (28) is brought into its pre-charge configuration (C_PCH) to energize a conductor (21) of a downstream electrical line downstream of the downstream point (38); and in that the closing control method includes, during or after the pre-charge step of the conductor, at least one parameter determination step (143) comprising the determination of at least one current or voltage parameter in the main circuit (34) or in the downstream electrical line, and a decision step (144), during which it is decided, based on the at least one parameter determined during the parameter determination step, whether or not to continue the complete closing (160) of the current breaking device by switching the current breaking device to the conduction configuration (C_COND).

15. The control method according to claim 14, characterized in that, to reach the conduction configuration (C_COND), the pre-charge switch (58) is opened before the closing of the breaking switch (42.i) and the isolation switch (48).

16. The control method according to any one of claims 14 or 15, characterized in that, if the decision step (143) is not positive, the method continues, without passing through the conduction configuration (C_COND) of the breaking device (28), with a recharging step (180) of the pre-charge capacitor (54.i) during which the breaking device (28) is brought into the charging configuration (C_CH), then successively with a new pre-charge step (C_PCH) of the conductor (21), a new parameter determination step (143), and a new decision step (144), according to a pre-charge cycle.

17. The control method according to claim 16, characterized in that the recharging step (180) of the pre-charge capacitor (54.i) comprises: - the closing of the isolation switch (48) and the closing of the pre-charge switch (58) to charge the pre-charge capacitor (54.i), while keeping the breaking switch (42.i) in its open state; - after said closing of the pre-charge switch (58), the reopening of the isolation switch (48).

18. The control method according to any one of claims 14 to 17, characterized in that, after at least one pre-charge step (141) of the conductor (21), the complete closing (160) of the current breaking device by switching the breaking device (28) to its conduction configuration (C_COND) is continued if a voltage value in the main circuit (34), or in the downstream electrical line, exceeds a threshold value.

19. A process for evaluating the integrity of an electrical conductor (21) in a power transmission line in an electrical installation (10) including a main high DC voltage source (17) electrically connected to an upstream end of the electrical conductor (21), with a breaking device (28) according to any one of the preceding claims, said breaking device (28) being considered as an upstream current breaking device interposed between the main voltage source (17) and the electrical conductor (21), and with a downstream end of the electrical conductor connected to another electrical breaking device (28) according to any one of the preceding claims, said other breaking device (28) being considered as a downstream current device, the evaluation process being of the type wherein, in an initial state, the upstream breaking device and the downstream breaking device are each respectively in an isolation configuration (C_SOL) so that, in the initial state, the electrical conductor (21) is, except for an electrical fault affecting the electrical conductor (21), electrically isolated from the installation (10) and the environment, the evaluation process including at least one pre-charge step of the conductor (21) during which an auxiliary voltage source, distinct from the main voltage source, is connected to the conductor (21) to energize the electrical conductor (21) while keeping the conductor (21) isolated from the main voltage source and from the rest of the electrical installation; the evaluation process including, during or after the pre-charge step of the conductor, at least one parameter determination step comprising the determination of at least one current or voltage parameter in the downstream electrical line, and an evaluation step during which the integrity of the electrical conductor (21) is evaluated based on the at least one parameter determined during the parameter determination step.