Current cut-off device for interrupting high-voltage DC path
By connecting auxiliary branches in parallel in the DC network, superimposed current is generated by using capacitor banks, inductors and commutation switches, the problem of difficult current crossing in the DC network is solved, and a compact and efficient design of current interruption is achieved.
Patent Information
- Application Number
- CN202411088276.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-11
- Filing Date
- 2024-08-09
- Publication Date
- 2025-02-18
AI Technical Summary
In DC networks, current does not naturally cross zero, making it difficult to use zero-crossing event interrupt current, and the existing current injection methods are complex, making it difficult to synchronize and control switches.
A current cut-off device is designed to generate superimposed current and generate current zero crossing in the main branch by connecting the auxiliary branch including a capacitor bank, an inductor and a commutation switch in parallel in the DC path, thereby achieving current interruption.
The device achieves current interruption through a limited number of components, is compact and cost-effective in design, simplifying the synchronization and control of the device and reducing complexity.
Smart Images
Figure CN119482302A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to medium voltage direct current (DC) power distribution systems, and more particularly to circuits and methods for interrupting current in a direct current (DC) path. Background Art
[0002] HVDC transmission is an interesting solution to reduce total network losses and integrate renewable energy sources such as wind or photovoltaic power. As a traditional AC network, DC networks need circuit breakers to protect them from short circuits.
[0003] In AC networks, the zero-crossing event of the current is used to extinguish the arc generated when the circuit is opened and to actually interrupt the current. A typical difficulty in operating a DC circuit breaker is that the current does not naturally cross zero.
[0004] In order to produce a zero-crossing event of the DC current, a method generally known as current injection was developed. According to this method, an oscillating circuit including a capacitor and an inductor is connected in parallel to the main path of the circuit breaker, and the current oscillations in the parallel circuit are superimposed on the DC current in the main path of the circuit breaker. The resulting current combination oscillates around and between zero points, allowing the current to be interrupted.
[0005] Different solutions have been proposed for current injection. These solutions usually involve various switches to charge and discharge the oscillating circuit. These switches can be difficult to synchronize and control, resulting in complex devices.
[0006] The proposed solution improves the design of known solutions. It proposes a circuit topology that interrupts the current in the DC network using some AC switchgear configuration. Summary of the invention
[0007] To this end, a current cut-off device is proposed, for interrupting the current in a high-voltage DC path between a first terminal and a second terminal, comprising:
[0008] - a main branch inserted in the DC path, comprising a first mechanical circuit breaker, the first mechanical circuit breaker being normally closed,
[0009] - a first auxiliary branch connected in parallel with the first mechanical circuit breaker, comprising a series connection of a capacitor bank, an inductor and a second mechanical circuit breaker called a reversing switch, the second mechanical circuit breaker being normally open,
[0010] - surge arresters connected in parallel with the capacitor bank,
[0011] - a second auxiliary branch connecting the first intermediate terminal comprised between the capacitor bank and the inductor to a ground connection, the second auxiliary branch comprising a resistor,
[0012] The second mechanical circuit breaker is configured to close the first auxiliary branch in response to the occurrence of a fault current in the main branch, thereby generating a current that is superimposed on the current in the main branch and causes a current zero crossing in the main branch.
[0013] This arrangement provides current interruption capability with a limited number of components, making the design cost-effective and compact.
[0014] The following features may be implemented individually or in combination:
[0015] In an embodiment of the current interruption device:
[0016] - a first terminal connected to a network source, and
[0017] - The second terminal is connected to the electrical load ring.
[0018] The main branch is the main electrical wire.
[0019] The first auxiliary branch is an auxiliary conductive line.
[0020] The second auxiliary branch is a third conductive line.
[0021] The current disconnect device is operable in a first mode, referred to as a normal operating mode, in which the first mechanical circuit breaker is in a closed state and the second mechanical circuit breaker is in an open state.
[0022] The current interrupting device may also operate in a second mode, referred to as a fault mode, wherein the first mechanical circuit breaker is in an open state and the second mechanical circuit breaker is in a closed state.
[0023] The current cut-off device may switch from a first mode to a second mode in response to the presence of a fault current in the main branch.
[0024] The current disconnect device can also operate in a third mode, referred to as a residual current interruption mode, in which the first mechanical circuit breaker is in an open state and the second mechanical circuit breaker is in an open state.
[0025] The current cut-off device may switch from the second mode to the third mode in response to a residual fault current occurring in the first auxiliary branch.
[0026] The current disconnect device can operate in a fourth mode, referred to as a normal operation mode after fault interruption, in which the first mechanical circuit breaker is in a closed state and the second mechanical circuit breaker is in an open state.
[0027] After the capacitor bank is recharged by the current flowing from the source side to the second auxiliary branch resistor, the current cutoff device may be switched from the third mode to the fourth mode.
[0028] The inductance of the inductor is between 10μH and 1mH.
[0029] The capacitance of the capacitor bank is between 3 μF and 300 μF.
[0030] The resistance of the resistor is higher than 1000 ohms.
[0031] The ratio of pole-to-ground voltage to resistance is less than 2A.
[0032] The product of inductance and capacitance is 3.10 -7 s 2 and 3.10 -11 s 2 between.
[0033] In an embodiment of the current disconnect device, the first auxiliary branch comprises a first connection to the main branch and a second connection to the main branch, the first connection being comprised between the first terminal and the first terminal of the first mechanical circuit breaker, and the second connection being comprised between the second terminal and the second terminal of the first mechanical circuit breaker.
[0034] The current cut-off device also includes:
[0035] - a third mechanical circuit breaker arranged on the first auxiliary branch, between the first connection of the first auxiliary branch to the main branch and the connection of the surge arrester to the capacitor bank,
[0036] - a fourth mechanical circuit breaker, arranged on the second auxiliary branch, between the first intermediate terminal and the resistor,
[0037] a third auxiliary branch connecting the second intermediate terminal comprised between the third mechanical circuit breaker and the capacitor bank to a third intermediate terminal comprised between the fourth circuit breaker and the resistor, the third auxiliary branch comprising a fifth circuit breaker.
[0038] The current disconnect device is configured to selectively operate:
[0039] - in a first configuration, the first terminal is connected to the source and the second terminal is connected to the electrical load ring, or
[0040] - In a second configuration, the first terminal is connected to the electrical load ring and the second terminal is connected to the source.
[0041] Each of the first mechanical circuit breaker, the second mechanical circuit breaker, and the third mechanical circuit breaker may include a vacuum circuit breaker.
[0042] The fourth mechanical circuit breaker and the fifth mechanical circuit breaker may also include vacuum circuit breakers.
[0043] By integrating a vacuum interrupter, the disconnection of residual currents can also be handled. Compared to prior art solutions, a dedicated residual switch is not necessary and can be omitted, making the device simpler.
[0044] The current cut-off device may further comprise a first switching device arranged on the first auxiliary branch between the inductor and the second connection of the first auxiliary branch to the main branch.
[0045] In an implementation example, the first switching device is arranged on the first auxiliary branch between the second mechanical circuit breaker and the second connection of the first auxiliary branch to the main branch.
[0046] The current cut-off device may further include a second switch device, which is arranged on the main branch and is located between the first connection between the first auxiliary branch and the main branch and the second connection between the first auxiliary branch and the main branch.
[0047] The current cut-off device may further comprise a third switch device arranged on the main branch between the first terminal of the first auxiliary branch and the first connection of the main branch.
[0048] The switching device provides the ability to safely discharge capacitors of the commutation circuit and provides safe grounding of the power or load side circuits, especially when the switching device is a grounding switch.
[0049] The current cut-off device may further comprise a fourth switch device arranged on the first auxiliary branch, between the first connection of the first auxiliary branch with the main branch and the second intermediate terminal.
[0050] The current cutoff device may further include a fifth switching device provided on the second auxiliary branch between the first intermediate terminal and the resistor.
[0051] In an implementation example, the fifth switching device is disposed between the first intermediate terminal and the fourth mechanical circuit breaker.
[0052] The current cutoff device may further include a sixth switching device arranged on the third auxiliary branch.
[0053] In an implementation example, the sixth switching device is disposed between the second intermediate terminal and the fifth mechanical circuit breaker.
[0054] Each switch device can be a two-position disconnector or a three-position switch.
[0055] In an embodiment of the current disconnect device, the first mechanical circuit breaker, the second mechanical circuit breaker and the third switch device are arranged in the first gas-insulated tank.
[0056] In an embodiment, the first mechanical circuit breaker, the second mechanical circuit breaker, the first switch device, the second switch device and the third switch device are arranged in a first gas insulated tank.
[0057] A third mechanical circuit breaker may be disposed in the first gas insulated tank.
[0058] The integration of different mechanical circuit breakers and switchgear in a common gas-insulated tank provides electrical insulation properties and environmental sensitivity, making the solution robust and reliable. In addition, when the first mechanical circuit breaker, the second mechanical circuit breaker and the third mechanical circuit breaker are arranged in the same gas-insulated tank as part of one switchgear, the correct synchronization of their operation becomes easier. The installation and future maintenance are simplified. Moreover, this integration of mechanical circuit breakers and switchgear in a common tank provides a more compact and cheaper solution compared to the alternative installation as separate equipment.
[0059] In an embodiment of the current interruption device, the capacitor bank, the inductor, the resistor and the surge arrester are arranged in a metal enclosed compartment.
[0060] The assembly of the current interruption device is easier when the capacitor bank, inductor, resistor and surge arrester form a pre-assembled module.
[0061] In an embodiment of the current interruption device, the fourth mechanical circuit breaker and the fifth mechanical circuit breaker are arranged in the second gas-insulated tank.
[0062] A resistor is also disposed in the second gas-insulated tank.
[0063] The fifth switch device and the sixth switch device may also be arranged in the second gas-insulated tank.
[0064] In an embodiment of the current interruption device, the capacitor bank, the inductor and the surge arrester are arranged in a metal enclosed compartment.
[0065] As mentioned previously, synchronization of the circuit breakers is simplified, as well as installation and future maintenance. BRIEF DESCRIPTION OF THE DRAWINGS
[0066] Other features, details and advantages will appear from the following detailed description and the accompanying drawings, in which:
[0067] Figure 1 is a schematic diagram of a first embodiment of the proposed circuit breaker,
[0068] Figure 2 is a schematic diagram of a second embodiment of the proposed circuit breaker,
[0069] Figure 3 yes Figure 1 A variation of the embodiment,
[0070] Figure 4 yes Figure 2 A variation of the embodiment,
[0071] Figure 5 is a schematic diagram showing the operation of the circuit breaker according to the first embodiment,
[0072] Figure 6 is a schematic diagram showing the operation of the circuit breaker according to the second embodiment,
[0073] Figure 7 represents the time evolution of some parameters during circuit breaker operation,
[0074] Figure 8 The time evolution of other parameters during circuit breaker operation is shown. DETAILED DESCRIPTION
[0075] For ease of reading, various elements are not necessarily drawn to scale. In these figures, identical elements receive identical reference numerals. Certain elements or parameters may be indexed, that is to say specified by, for example, "first element" or "second element", or first parameter and second parameter, etc. The purpose of such indexing is to distinguish between similar but not identical elements or parameters. Such indexing does not mean that one element or one parameter takes precedence over another, and their names are interchangeable. When referring to a subsystem including a given element, it is not excluded that other elements exist in the subsystem.
[0076] Figure 1 A first embodiment of a current disconnect device 20 for interrupting the flow of current in a high voltage direct current (DC) path between a first terminal T1 and a second terminal T2 is schematically shown.
[0077] The proposed current cut-off device 20 for interrupting the current flow in the high voltage DC path between the first terminal T1 and the second terminal T2 comprises:
[0078] - a main branch A inserted in the DC path, comprising a first mechanical circuit breaker CB1, the first mechanical circuit breaker CB being normally closed,
[0079] a first auxiliary branch B connected in parallel with the first mechanical circuit breaker CB1, comprising a series connection of a capacitor bank CA, an inductor IN and a second mechanical circuit breaker CB2, called a reversing switch, the second mechanical circuit breaker CB2 being normally open,
[0080] - a surge arrester SA connected in parallel to the capacitor bank CA,
[0081] a second auxiliary branch C connecting the first intermediate terminal I1 comprised between the capacitor bank CA and the inductor IN to the ground connection EC, the second auxiliary branch C comprising a resistor R.
[0082] The second mechanical circuit breaker CB2 is configured to close the first auxiliary branch B in response to the occurrence of a fault current in the main branch A so as to generate a current that is superimposed on the current in the main branch A and causes a current zero crossing in the main branch A.
[0083] According to a first embodiment of the current cut-off device 20 , the first terminal T1 is connected to the source S of the network and the second terminal T2 is connected to the electrical load L ring.
[0084] In other words, in this embodiment, the current circulation in the main branch A is unidirectional. The current flows in the direction indicated by the arrow f1.
[0085] By definition, in the context of the present invention, a power source is an electrical node that provides electrical energy.
[0086] In contrast, an electrical load is an electrical node that consumes electrical energy.
[0087] The main branch A is the main power line.
[0088] The first auxiliary branch B is a second conductive line.
[0089] The second auxiliary branch C is a third conductive line.
[0090] By definition, a normally open circuit breaker is one in which the gap between the contacts is guaranteed by default, so the flow of current is interrupted.
[0091] Normally closed circuit breakers are those in which the continuity of the contacts is guaranteed by default, thus allowing the flow of current.
[0092] A normally closed circuit breaker may open in response to an electrical fault occurring in a circuit branch that includes the circuit breaker.
[0093] The current disconnect device 20 can operate in a first mode, referred to as a normal operating mode, in which the first mechanical circuit breaker CB1 is in a closed state and the second mechanical circuit breaker CB2 is in an open state.
[0094] In this mode, current flows through the main branch A, and no current flows through the first auxiliary branch B and the second auxiliary branch C.
[0095] The current disconnect device 20 can operate in a second mode, referred to as a fault mode, in which the first mechanical circuit breaker CB1 is in an open state and the second mechanical circuit breaker CB2 is in a closed state.
[0096] The current cut-off device 20 can switch from the first mode to the second mode in response to the occurrence of a fault current in the main branch A.
[0097] The current disconnect device 20 can also operate in a third mode, referred to as a residual current interruption mode, in which the first mechanical circuit breaker CB1 is in an open state and the second mechanical circuit breaker CB2 is in an open state.
[0098] The current cut-off device 20 may be switched from the second mode to the third mode in response to a residual fault current occurring in the first auxiliary branch B.
[0099] The current disconnect device 20 can operate in a fourth mode, referred to as a normal operation mode after fault interruption, in which the first mechanical circuit breaker CB1 is in a closed state and the second mechanical circuit breaker CB2 is in an open state.
[0100] After the capacitor bank CA is recharged by the current flowing from the source side S to the resistor R of the second auxiliary branch C, the current cutoff device 20 may be switched from the third mode to the fourth mode.
[0101] The inductance of the inductor L is between 10 μH and 1 mH.
[0102] The capacitance of the capacitor bank CA is between 3 μF and 300 μF.
[0103] The resistance of the resistor R is higher than 1000 ohms.
[0104] The ratio of pole-to-ground voltage to resistance is less than 2A.
[0105] The product of inductance and capacitance is 3.10 -11 s 2 and 3.10 -7 s 2 between.
[0106] Figure 2 A second embodiment of a current interruption device 20 is schematically illustrated. The first auxiliary branch B comprises a first connection C1 to the main branch A and a second connection C2 to the main branch A.
[0107] The first connection C1 is comprised between the first terminal T1 and the first terminal CB1a of the first mechanical circuit breaker CB1. The second connection C2 is comprised between the second terminal T2 and the second terminal CB1b of the first mechanical circuit breaker CB1.
[0108] The current cut-off device 20 also includes:
[0109] a third mechanical circuit breaker CB3, arranged on the first auxiliary branch B, between the first connection C1 of the first auxiliary branch B to the main branch A and the first connection P1 of the surge arrester SA to the capacitor bank CA,
[0110] a fourth mechanical circuit breaker CB4, arranged on the second auxiliary branch C, between the first intermediate terminal I1 and the resistor R,
[0111] a third auxiliary branch D, connecting the second intermediate terminal I2 comprised between the third mechanical circuit breaker CB3 and the capacitor bank CA to the third intermediate terminal I3 comprised between the fourth circuit breaker CB4 and the resistor R, the third auxiliary branch D comprising a fifth circuit breaker CB5.
[0112] A first terminal of the resistor R is directly connected to the ground Ec.
[0113] The second terminal of the resistor R is connected to a first terminal of the capacitor bank CA, called the first intermediate terminal I1 , through a portion of the second auxiliary branch C comprising a fourth mechanical circuit breaker CB4 .
[0114] The second terminal of the resistor R is also connected to a second terminal of the capacitor bank CA, called the second intermediate terminal I2, through a portion of the third auxiliary branch D comprising a fifth mechanical circuit breaker CB5.
[0115] The surge arrester SA and the capacitor bank CA are connected in parallel between the first intermediate terminal I1 and the second intermediate terminal I2 .
[0116] A first terminal of the inductor IN is directly connected to the first intermediate terminal I1 .
[0117] A second terminal of the inductor IN is connected to the main branch A via a second mechanical circuit breaker CB2.
[0118] The first connection P1 of the surge arrester SA and the capacitor bank CA may merge with the second intermediate terminal I2 in which the third auxiliary branch D is connected to the first auxiliary branch B. In other words, the first connection P1 may coincide with the second intermediate terminal I2.
[0119] The first intermediate terminal I1 may merge with the second connection P2 of the surge arrester SA and the capacitor bank CA, in which the second auxiliary branch C is connected to the first auxiliary branch B. In other words, the first intermediate terminal I1 may coincide with the second connection P2.
[0120] The current interrupt device 20 is configured to selectively operate:
[0121] - in a first configuration, the first terminal T1 is connected to a power source S and the second terminal T2 is connected to an electrical load L ring, or
[0122] In a second configuration, the first terminal T1 is connected to the electrical load L-loop and the second terminal T2 is connected to the power source S.
[0123] In the second embodiment, the current circulation in the main branch A can be bidirectional. The positions of the power source S and the electric load L can be exchanged according to the configuration required by the power grid. In other words, the current interruption device 20 is suitable for the configuration of the power grid.
[0124] In a configuration where the first terminal is connected to the power source S and the second terminal is connected to the electrical load L loop, the current circulates in the direction indicated by the arrow f1 ′.
[0125] In another configuration, the first terminal is connected to an electrical load L and the second terminal is connected to a power source S, and the current circulates in the direction indicated by arrow F2'.
[0126] In a second embodiment, when the fault current is interrupted, the capacitor bank CA can be charged in two configurations of the network.
[0127] When the first terminal T1 is connected to the power source, the capacitor is charged by closing the third mechanical circuit breaker CB3 and the fourth mechanical circuit breaker CB4.
[0128] When the second terminal T2 is connected to the power source, the capacitor is charged by closing the second mechanical circuit breaker CB2 and the fifth mechanical circuit breaker CB5.
[0129] Once the capacitor is charged, the first circuit breaker CB1 can be closed to restore the current circulation in the main branch A. In the event that the fault still exists, the current disconnection device 20 will trigger the current interruption again.
[0130] Each of the first mechanical circuit breaker CB1 , the second mechanical circuit breaker CB2 , and the third mechanical circuit breaker CB3 may include a vacuum circuit breaker.
[0131] The current cut-off device 20 further comprises a first switching device SD1 , which is arranged on the first auxiliary branch B, between the inductor IN and the second connection C2 of the first auxiliary branch B and the main branch A.
[0132] In the example shown, the first switching device SD1 is arranged on the first auxiliary branch B, between the second mechanical circuit breaker CB2 and the second connection C2 of the first auxiliary branch B and the main branch A.
[0133] The first switching device SD1 is present in the first and second embodiments.
[0134] The current disconnect device 20 further comprises a second switch device SD2 , which is arranged on the main branch A and is located between a first connection C1 between the first auxiliary branch B and the main branch A and a second connection C2 between the first auxiliary branch B and the main branch A.
[0135] The first auxiliary branch B is connected in parallel with a portion of the associated main branch A comprising a series connection of a first mechanical circuit breaker CB1 and a second switching device SD2.
[0136] The current disconnect device 20 further comprises a third first switching device SD3 which is arranged on the main branch A and between the first terminal T1 and the first connection C1 of the first auxiliary branch B and the main branch A.
[0137] The second switching device SD2 and the third switching device SD3 exist in the first and second embodiments.
[0138] The switching devices SD1, SD2 provide the ability to safely discharge capacitors of the commutation circuit and provide safe grounding of the power or load side circuits, especially when the switching devices are grounding switches.
[0139] In the second embodiment, the current cut-off device 20 further comprises a fourth switch device SD4 which is arranged on the first auxiliary branch B and between the first auxiliary branch B and the first connection C1 of the main branch A and the second intermediate terminal I2 .
[0140] The portion of the first auxiliary branch B comprised between its first connection C1 to the main branch A and its connection I2 to the third auxiliary branch D comprises a fourth switching device SD4 and a third mechanical breaker CB3 connected in series.
[0141] Similarly, the portion of the first auxiliary branch B comprised between its second connection C2 with the main branch A and its connection I1 with the second auxiliary branch C comprises a first switching device SD1 and a second mechanical breaker CB2 connected in series.
[0142] The current cut-off device 20 may further include a fifth switching device SD5 disposed on the second auxiliary branch C between the first intermediate terminal I1 and the resistor R.
[0143] In the illustrated example, the fifth switching device SD5 is arranged between the first intermediate terminal I1 and the fourth mechanical circuit breaker CB4 .
[0144] The current cut-off device 20 further includes a sixth switching device SD6 disposed on the third auxiliary branch D.
[0145] In the illustrated example, the sixth switching device SD6 is arranged between the second intermediate terminal I2 and the fifth mechanical circuit breaker CB5 .
[0146] Each switch device SD1, SD2, SD3, SD4, SD5, SD6 can be a two-position disconnector or a three-position switch.
[0147] A two-position disconnector has only two stable positions: the first position, called the closed position, in which the movable contact is in contact with the fixed contact, allowing the current to flow; the second position, called the open position, in which the movable contact is separated from the fixed contact, interrupting the current flow. This type of disconnector is also called an isolator switch.
[0148] A three-position disconnector has three stable positions: the two already mentioned, plus a third position in which the movable contact is earthed. This type of disconnector is also called an earthing switch.
[0149] Each mechanical circuit breaker CB2, CB3, CB4, CB5 is associated with a series connected switching device SD1, SD4, SD5, SD6, respectively.
[0150] Figure 5 , 6 , 7 and 8 illustrate the operation of the circuit breaker 20 when a circuit fault occurs.
[0151] Figure 5 Involved Figure 1 The architecture of the first embodiment is shown. Figure 6 Involved Figure 2 The architecture of the second embodiment is shown.
[0152] Figure 7 and Figure 8 Applicable to both embodiments.
[0153] exist Figure 7 , curve Gr1 shows the time evolution of the current intensity in the portion of the main branch A comprised between the first connection Cl and the second connection C2, thus comprising the first mechanical circuit breaker CB1. This current reflects the load current, on which the fault current may be superimposed in the event of a fault.
[0154] Curve Gr2 shows the time evolution of the current in the first auxiliary branch B.
[0155] Curve Gr3 shows the time evolution of the current in the surge arrester SA.
[0156] exist Figure 8 In FIG. 1 , curve Gr4 shows the time evolution of the voltage across the first mechanical circuit breaker CB1. Figure 7 The same as in.
[0157] The load current intensity is rated between time t0 and time t1, and the steady-state value is about 2000A.
[0158] The instant t1 corresponds to the occurrence of a fault, such as a short circuit, which causes a sharp increase in the current intensity. The time window between t1 and t2 corresponds to the opening phase of the first mechanical circuit breaker CB1. During the same time window, the closing phase of the second mechanical circuit breaker CB2 is initiated.
[0159] The time t2 corresponds to the second mechanical circuit breaker CB2 closing the first auxiliary branch B. The first mechanical circuit breaker CB1 and the second mechanical circuit breaker CB2 are in the state corresponding to Figure 5An oscillating current is generated in the first auxiliary branch B, which is superimposed on the current in the main branch A. The oscillating current includes a positive peak followed by a negative peak. The negative peak causes the zero crossing of the curve Gr1 at time t3. With the first mechanical circuit breaker CB1 in the open state and the current crossing zero, the current in the main branch A is interrupted.
[0160] Curve Gr3 shows the action of the surge arrester SA, where the surge arrester limits the current between the instants t4 and t5, protecting the circuit from the effects of a fault.
[0161] After the current is interrupted at time t3 , the second mechanical circuit breaker is opened again and the current reaches zero at time t6 .
[0162] exist Figure 5 In the figure, for the first embodiment, the arrows marked g1 illustrate the current cycle of charging the capacitor bank CA after the current in the main branch A is interrupted, so as to be able to disconnect the main branch A again if the electrical fault in the main branch A still exists.
[0163] Similarly, for the second embodiment, the arrows labeled g1 ′ and g2 ′ show the current circulation for recharging the capacitor bank CA after the current in the main branch A is interrupted.
[0164] The notation g1' corresponds to a configuration in which the power supply of the network is connected to the T1 terminal and the load is connected to the T2 terminal.
[0165] The reference g2' corresponds to another configuration in which the load of the network is connected to the T1 terminal and the power supply is connected to the T2 terminal.
[0166] Figure 3 An embodiment of a current interruption device 20 is shown, derived from Figure 1 The first embodiment shown. Figure 3 In the embodiment of the present invention, the first mechanical circuit breaker CB1, the second mechanical circuit breaker CB2 and the third switch device SD3 are arranged in the first gas insulation tank 11.
[0167] In the present embodiment, the first switch device SD1 and the second switch device SD2 are also disposed in the same gas insulation tank 11 .
[0168] In other words, the first mechanical circuit breaker CB1 , the second mechanical circuit breaker CB2 , the first switching device SD1 , the second switching device SD2 , and the third switching device SD3 are provided in the first gas insulated tank 11 .
[0169] Integrating the different mechanical circuit breakers CB1, CB2, CB3 and the switchgear SD1, SD2, SD3 in a common gas-insulated tank 11 provides electrical insulation properties and environmental sensitivity, making the solution robust and reliable. In addition, the synchronization of the operation of the first CB1, second CB2 and third CB3 mechanical circuit breakers is simplified due to the arrangement in the common gas-insulated tank 11. Installation and future maintenance are simplified. In addition, integrating the mechanical circuit breakers and the switchgear in a common tank makes the solution more compact and cheaper.
[0170] exist Figure 3 In the embodiment of FIG. 1 , the capacitor bank CA, the inductor IN, the resistor R and the surge arrester SA are arranged in a metal enclosed compartment 13 .
[0171] When the capacitor bank CA, the inductor IN, the resistor R and the surge arrester SA can form a pre-assembled module, the assembly of the current cut-off device 20 is easier.
[0172] Figure 4 An embodiment of a current interruption device 20 is shown, derived from Figure 2 The second embodiment is shown.
[0173] The first mechanical circuit breaker CB1, the second mechanical circuit breaker CB2, the first switch device SD1, the second switch device SD2 and the third switch device SD3 are provided in the first gas insulation tank 11. In addition, the fourth switch device SD4 and the third mechanical circuit breaker CB3 are also provided in the same first gas insulation tank 11.
[0174] exist Figure 4 In the embodiment of the current interruption device 20 shown, the fourth mechanical circuit breaker CB4 and the fifth mechanical circuit breaker CB5 are arranged in the second gas insulation tank 12. In addition, the resistor R is also arranged in the second gas insulation tank 12. The fifth switch device SD5 and the sixth switch device SD6 are also arranged in the second gas insulation tank 12.
[0175] As mentioned before, the synchronization of the different circuit breakers CB4, CB5 is simplified, as well as the installation and future maintenance.
[0176] In this embodiment, the capacitor bank CA, the inductor IN and the surge arrester SA are arranged in a metal enclosed compartment 13 ′.
Claims
1. A current cut-off device (20) for interrupting the flow of current in a high-voltage direct current path between a first terminal (T1) and a second terminal (T2), comprising: - a main branch (A) inserted in the DC path, comprising a first mechanical circuit breaker (CB1), the first mechanical circuit breaker (CB1) being normally closed, a first auxiliary branch (B), connected in parallel to the first mechanical circuit breaker (CB1), comprising a series connection of a capacitor bank (CA), an inductor (IN) and a second mechanical circuit breaker (CB2), called a reversing switch, the second mechanical circuit breaker (CB2) being normally open, - a surge arrester (SA) connected in parallel with the capacitor bank (CA), - a second auxiliary branch (C) connecting the first intermediate terminal (I1) comprised between the capacitor bank (CA) and the inductor (IN) to the ground connection (EC), the second auxiliary branch (C) comprising a resistor (R), The second mechanical circuit breaker (CB2) is configured to close the first auxiliary branch (B) in response to the occurrence of a fault current in the main branch (A), thereby generating a current that is superimposed on the current in the main branch (A) and causes a current zero crossing in the main branch (A).
2. The current interruption device (20) according to claim 1, wherein: - a first terminal (T1) connected to a power source (S) of the network, and - The second terminal (T2) is connected to the electrical load (L) ring.
3. A current interruption device (20) according to claim 1, wherein the first auxiliary branch (B) comprises a first connection (C1) to the main branch (A) and a second connection (C2) to the main branch (A), the first connection (C1) being comprised between the first terminal (T1) and the first terminal of the first mechanical circuit breaker (CB1), the second connection (C2) being comprised between the second terminal (T2) and the second terminal of the first mechanical circuit breaker (CB1), The current cut-off device (20) further comprises: - a third mechanical circuit breaker (CB3) arranged on the first auxiliary branch (B) between the first connection (C1) of the first auxiliary branch (B) to the main branch (A) and the connection (P1) of the surge arrester (SA) to the capacitor bank (CA), - a fourth mechanical circuit breaker (CB4), arranged on the second auxiliary branch (C), between the first intermediate terminal (I1) and the resistor (R), - a third auxiliary branch (D), connecting a second intermediate terminal (I2) included between a third mechanical circuit breaker (CB3) and a capacitor bank (CA) to a third intermediate terminal (I3) included between a fourth circuit breaker (CB4) and a resistor (R), the third auxiliary branch (D) including a fifth circuit breaker (CB5).
4. The current interruption device (20) according to claim 3, configured to selectively operate: - in a first configuration, wherein the first terminal (T1) is connected to a power source (S) and the second terminal (T2) is connected to an electrical load (L) loop, or - In a second configuration, wherein the first terminal (T1) is connected to the electrical load (L) loop and the second terminal (T2) is connected to the power source (S).
5. The current cut-off device (20) according to any of the preceding claims, further comprising a first switching device (SD1) arranged on the first auxiliary branch (B), between the inductor (IN) and the second connection (C2) of the first auxiliary branch (B) and the main branch (A).
6. The current cut-off device (20) according to any one of the preceding claims further comprises a second switching device (SD2), wherein the second switching device (SD2) is arranged on the main branch (A) and is located between the first connection (C1) between the first auxiliary branch (B) and the main branch (A) and the second connection (C2) between the first auxiliary branch (B) and the main branch (A).
7. The current cut-off device (20) according to any of the preceding claims in combination with claim 3 further comprises a third switching device (SD3) arranged on the main branch (A) between the first terminal (T1) and the first connection (C1) of the first auxiliary branch (B) and the main branch (A).
8. The current cut-off device (20) according to any one of claims 4 to 7 in combination with the current cut-off device (20) according to claim 3, further comprising a fourth switching device (SD4), which is arranged on the first auxiliary branch (B) and is located between the first connection (C1) of the first auxiliary branch (B) and the main branch (A) and the second intermediate terminal (I2).
9. The current cut-off device (20) according to any one of claims 4 to 8, further comprising a fifth switching device (SD5) arranged on the second auxiliary branch (C) between the first intermediate terminal (I1) and the resistor (R).
10. The current cut-off device (20) according to any one of claims 4 to 9 in combination with claim 3, further comprising a sixth switching device (SD6) arranged on the third auxiliary branch (D).
11. The current disconnect device (20) according to any of the preceding claims in combination with claim 7, wherein the first mechanical circuit breaker (CB1), the second mechanical circuit breaker (CB2) and the third switch device (SD3) are arranged in the first gas insulated tank (11).
12. According to claim 11 in combination with the current disconnecting device (20) described in claims 5 and 6, wherein the first mechanical circuit breaker (CB1), the second mechanical circuit breaker (CB2), the first switching device (SD1), the second switching device (SD2) and the third switching device (SD3) are arranged in the first gas insulated tank (11).
13. The current interruption device (20) according to claim 11 or 12 in combination with claim 3, wherein the third mechanical circuit breaker (CB3) is arranged in the first gas-insulated tank (11).
14. The current disconnect device (20) according to any one of the preceding claims, wherein the capacitor bank (CA), the inductor (IN), the resistor (R) and the surge arrester (SA) are arranged in a metal-enclosed compartment (13).
15. The current disconnect device (20) according to any of the preceding claims in combination with claim 3, wherein the fourth mechanical circuit breaker (CB4) and the fifth mechanical circuit breaker (CB5) are arranged in a second gas insulated tank (12).