All-solid-state on-off structure for split conductor on-line uninterrupted ice melting device

Abstract

The invention provides an all-solid-state on-off structure for a split conductor on-line uninterrupted ice melting device. The all-solid-state power unit is composed of a series of multi-unit series-parallel connection structures corresponding to sub-conductors of a split conductor, in the multi-unit series-parallel connection structures, each all-solid-state power unit comprises an insulated gate bipolar transistor, an anti-parallel diode, a voltage limiting circuit and an overvoltage protection device, and synchronous on-off is achieved by controlling a driving unit. According to the on-off structure, on the basis of an IGBT, a common-emitting-stage circuit breaker topological unit and a passive RCD buffer circuit are constructed. The multi-unit series-parallel configuration improves the voltage resistance and the through-current capability, has the advantages of fast response, high reliability, good electromagnetic compatibility and the like, can melt ice, replace a mechanical switch, avoid mechanical faults and ensure stable operation in a high-voltage environment without interrupting power supply, and is of great significance for improving the reliability of a power grid in atrocious weather.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage power transmission, and particularly to a fully solid-state breaking structure for an on-line power-off-free ice melting device for bundled conductors. Background Art

[0002] With the continuous expansion of the scale of the power system and the wide distribution of the power transmission network, the problem of icing on power lines has become one of the important factors affecting the safe and stable operation of the power grid. Under low-temperature and high-humidity conditions in winter, transmission lines are extremely prone to icing, which not only increases the mechanical load of the lines, but also may cause serious faults such as phase-to-phase short circuits, tripping, and wire breakage, posing a serious threat to the safe operation of the power system.

[0003] In recent years, the on-line power-off-free ice melting technology has gradually become a research hotspot, and its core lies in realizing the ice melting operation of the bundled conductors of the transmission line without interrupting the normal power supply. Such technologies usually require dedicated breaking devices to introduce or cut out the ice melting current into or from the line at specific moments. Traditional breaking devices mainly use mechanical circuit breakers, which have disadvantages such as slow operation speed, low reliability, and easy generation of electric arcs, and are difficult to meet the requirements of fast response and high reliability for on-line ice melting.

[0004] It should be noted that the information disclosed in the above background art section is only for understanding the background of the present application, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0005] The main object of the present invention is to overcome the defects existing in the above background art, and provide a fully solid-state breaking structure for an on-line power-off-free ice melting device for bundled conductors.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A fully solid-state breaking structure for an on-line power-off-free ice melting device for bundled conductors, comprising: A series of multi-unit series-parallel structures, each multi-unit series-parallel structure is correspondingly configured with one sub-conductor in the bundled conductors, and in each multi-unit series-parallel structure, a plurality of fully solid-state power units are connected in series to form a plurality of series branches, and the plurality of series branches are connected in parallel; Wherein, the fully solid-state power unit includes: an anti-parallel topology composed of a pair of insulated gate bipolar transistors connected in common emitter and an anti-parallel diode to realize bidirectional current conduction and blocking; a voltage-limiting circuit, an RCD voltage-limiting module composed of a resistor, a capacitor, and a diode, which is connected in parallel across each insulated gate bipolar transistor; an over-voltage protection device, which is connected in parallel across each insulated gate bipolar transistor; A control drive unit, electrically connected to the gates of each insulated gate bipolar transistor, and each full-solid-state power unit in the multi-unit series-parallel structure realizes synchronous turn-on and turn-off through the control of the control drive unit; Among them, the two ports of each multi-unit series-parallel structure are respectively connected to the two connection points of each sub-conductor of the split conductor and fixed at the conductor connection of the transmission tower.

[0007] Further, in the multi-unit series-parallel structure: The number of series branches is determined by the voltage difference borne when the switch is off to ensure that the voltage of a single full-solid-state power unit is within a safe range; The number of parallel branches is determined by the instantaneous maximum current in the ice melting state to increase the current-carrying capacity of the system.

[0008] Further, the voltage difference is calculated according to the following formula: ;

[0009] Among them, is the voltage difference at the short-circuit point on the current-carrying sub-conductor and at a distance from the short-circuit point is the phase current of the current-carrying sub-conductor, is the distance to the short-circuit point, is the resistance per unit length of the sub-conductor, is the inductance of the sub-conductor in the case of one current-carrying and one current-breaking.

[0010] Further, the parameters of the RCD voltage-limiting module satisfy the following formula: ; Among them, C is the capacitance value, is the stray inductance in the IGBT turn-off loop; The resistance R value should satisfy the following formula: ; Among them, is the maximum value of the collector current of the IGBT.

[0011] Further, the actual number of series-parallel branches is a 1.5-fold redundant configuration of the calculated number.

[0012] Further, the multi-unit series-parallel structure further includes: A buffer impedance element connecting each full-solid-state power unit, used to suppress the circulating current and oscillation between units.

[0013] Further, the control drive unit satisfies: The gate control signals output to each insulated gate bipolar transistor in the multi-unit series-parallel structure are synchronized in timing, and the time difference is within the set acceptable error range; The gate control signals of all insulated gate bipolar transistors on the same sub-conductor are the same.

[0014] In some embodiments, the all-solid-state breaking structure of the present invention for the on-line power-off ice melting device of split conductors includes: an all-solid-state power unit, the all-solid-state power unit includes an insulated gate bipolar transistor (IGBT) connected in common emitter and an anti-parallel diode; a voltage limiting circuit, the voltage limiting circuit includes an RCD voltage limiting structure composed of a resistor, a capacitor and a diode; an overvoltage protection device; a multi-unit series-parallel structure, the all-solid-state breaking structure is expected to be applied to high-voltage transmission lines, and has high requirements for both the turn-off voltage and the turn-on current, so the multi-unit series-parallel structure includes a series and parallel configuration of multiple all-solid-state power units; a control and drive unit, electrically connected to the control end of the all-solid-state power unit, for providing an isolated drive signal and realizing turn-on and turn-off control; Among them, the common emitter insulated gate bipolar transistor has a bidirectional conduction function. The series-parallel structure composed of this unit should have two ports, which are respectively connected to the jumper connection points of the two split conductors on the tower; the RCD module of the voltage limiting circuit should be connected in parallel at both ends of each unit, and the number of RCD modules should be exactly the same as the number of anti-parallel power modules; the metal oxide varistor overvoltage protection device is connected in parallel at both ends of each group of all-solid-state power units; the output port of the control and drive unit should align with the gate regions of the insulated gate bipolar transistors in each anti-parallel power module, and the gate control signals of the same sub-conductor should be the same and synchronized in timing. It is required that the time difference from the control signal to the gate should be within the acceptable error range; the breaking structure described in this patent should be completely placed in the on-line power-off ice melting device of split conductors, receive signals from the monitoring module and the total control module of the ice melting device, and be fixed at the connection points of the two conductors of the transmission tower to realize the transfer of the ice melting current on the sub-conductor.

[0015] Among them, the all-solid-state power unit includes: a first insulated gate bipolar transistor and a second insulated gate bipolar transistor, a first diode and a second diode; the emitter of the first insulated gate bipolar transistor is connected to the emitter of the second insulated gate bipolar transistor, the cathode of the first diode is connected to the collector of the first insulated gate bipolar transistor, and the cathode of the second diode is connected to the collector of the second insulated gate bipolar transistor to form an anti-parallel structure; the gates of the first insulated gate bipolar transistor and the second insulated gate bipolar transistor are respectively connected to the control and drive unit for independently receiving control signals with the same timing; the anti-parallel structure can realize the functions of bidirectional current conduction and blocking, and is suitable for the opening and closing operations of AC circuits.

[0016] Among them, the voltage-limiting circuit includes an RCD voltage-limiting circuit composed of a resistor, a capacitor and a diode. The RCD voltage-limiting circuit is connected in parallel with the corresponding insulated gate bipolar transistor. Among them, the resistor is connected in parallel with the diode. In the composed parallel structure, the parallel port on the cathode side of the diode is connected to the capacitor, that is, the parallel structure composed of the resistor and the diode is connected in series with the capacitor to form a complete voltage-limiting module. The resistor is used to limit the overvoltage amplitude during the breaking process, the capacitor is used to absorb the transient energy during the breaking process and control the voltage rise rate, and the diode is used to provide a unidirectional conduction path to ensure capacitor discharge. The impedance parameters of the voltage-limiting circuit match the parasitic parameters of the insulated gate bipolar transistor to ensure uniform voltage distribution in the multi-unit structure and improve the voltage withstand capacity and reliability of the system.

[0017] Among them, the metal oxide varistor is connected in parallel at both ends of each all-solid-state power unit. The rated operating voltage of the metal oxide varistor is higher than the normal operating voltage of the all-solid-state power unit and lower than the maximum voltage withstand value of the all-solid-state power unit. When a transient overvoltage occurs in the system, the metal oxide varistor conducts to absorb the excess energy and limits the voltage amplitude at both ends of the all-solid-state power unit.

[0018] Among them, the multi-unit series-parallel structure includes: multiple all-solid-state power units are connected in series to form multiple series branches, and the multiple series branches are connected in parallel to form a complete breaking unit. The number of all-solid-state power units in each series branch is determined according to the voltage difference in the switch-off scenario to ensure that the voltage borne by each all-solid-state power unit is within a safe range. The number of parallel branches is determined according to the instantaneous maximum current that can pass through the sub-conductor in the ice-melting state to improve the current-carrying capacity of the system. Redundancy also needs to be considered in the series-parallel structure. Since the breaking structure is applied to the main transmission line with a higher voltage level, the actual number of series-parallel branches that is 1.5 times the calculated number of series-parallel branches needs to be applied. Each all-solid-state power unit in the multi-unit series-parallel structure realizes synchronous turn-on and turn-off through the control and drive unit to ensure uniform distribution of voltage and current. The multi-unit series-parallel structure also includes buffer impedance elements connecting each unit, which are used to suppress the circulating current and oscillation phenomenon between units.

[0019] The present invention has the following beneficial effects: The present invention proposes a fully solid-state breaking structure for an on-line power-off ice melting device for bundled conductors. This structure uses fully solid-state IGBTs as the core power electronic devices, constructs a circuit breaker unit through an anti-parallel topology, and realizes the voltage limiting function by using a passive RCD circuit. The present invention designs a multi-unit series-parallel configuration scheme, effectively improving the voltage withstand capacity and current-carrying capacity of the system, and adapting to the voltage and current requirements of high-voltage lines. This breaking structure has the advantages of fast response speed, high reliability, and good electromagnetic compatibility, and can realize the ice melting operation of high-voltage lines without interrupting power supply, solving the technical problem that traditional ice melting methods require power outage. The fully solid-state breaking structure of the present invention replaces mechanical switches, eliminates the aging of mechanical components and arc hazards, avoids potential breaking failures of mechanical switches in extreme environments such as cold and humid, and at the same time, the optimized anti-parallel topology and RCD voltage limiting circuit design ensure the stable operation of the system in a high-voltage environment. Using the present invention to achieve reliable breaking during the ice melting process of high-voltage lines, during the whole process, power grid users cannot perceive power supply interruption, realizing "ice melting without power outage" in the true sense. The solution of the present invention provides key support for the on-line power-off ice melting technology of transmission lines and is of great significance for improving the operation reliability of the power grid under harsh climate conditions.

[0020] Other beneficial effects in the embodiments of the present invention will be further described below. Brief Description of the Drawings

[0021] Figure 1 Shows the basic unit of the IGBT common collector connection in the breaking structure of the embodiment of the present invention.

[0022] Figure 2 Shows the specific topology of the RCD voltage limiting circuit and overvoltage protection device in the embodiment of the present invention.

[0023] Figure 3 Shows the overall topology of the complete breaking structure in the embodiment of the present invention.

[0024] Figure 4 Shows an example of the switch structure arranged on one of the sub-conductors of a four-bundled conductor. Detailed Description of the Embodiment

[0025] The following makes a detailed description of the embodiments of the present invention. It should be emphasized that the following description is merely exemplary and not intended to limit the scope of the present invention and its applications.

[0026] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, the connection can be for a fixing function or for a coupling or communicating function.

[0027] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0028] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, the meaning of "a plurality of" is two or more, unless otherwise specifically and clearly defined.

[0029] The present invention provides a fully solid-state breaking structure for an on-line power-off ice melting device for bundled conductors. Through an anti-parallel IGBT topology, an RCD voltage-limiting circuit, a multi-unit series-parallel configuration, and a control and drive unit, reliable breaking during the ice melting process of high-voltage lines is achieved, providing key support for the on-line power-off ice melting technology of transmission lines.

[0030] Refer to Figures 1 to 4, an embodiment of the present invention provides a fully solid-state breaking structure for an on-line power-off ice melting device for bundled conductors, including a control and drive unit and a series of multi-unit series-parallel structures. Each multi-unit series-parallel structure is correspondingly configured with one sub-conductor in the bundled conductor. In each multi-unit series-parallel structure, multiple fully solid-state power units are connected in series to form multiple series branches, and the multiple series branches are connected in parallel. Among them, the fully solid-state power unit includes: an anti-parallel topology composed of a pair of insulated gate bipolar transistors (IGBTs) connected in common emitter and an anti-parallel diode to achieve bi-directional current conduction and blocking; a voltage limiting circuit, composed of a resistor R, a capacitor C, and a diode D to form an RCD voltage limiting module, which is connected in parallel across each insulated gate bipolar transistor; an over-voltage protection device, connected in parallel across each insulated gate bipolar transistor. This breaking structure is based on IGBTs to construct a common emitter circuit breaker topology unit and a passive RCD buffer circuit. The multi-unit series-parallel configuration improves the voltage withstand and current-carrying capabilities. The control and drive unit is electrically connected to the gates of each insulated gate bipolar transistor, and each fully solid-state power unit in the multi-unit series-parallel structure realizes synchronous turn-on and turn-off through the control of the control and drive unit. Among them, the two ports of each multi-unit series-parallel structure are respectively connected to the jumper strings of two sections of bundled conductors at the transmission tower.

[0031] In some embodiments, the timing of the gate control signals output by the control and drive unit to the gates of each insulated gate bipolar transistor in the multi-unit series-parallel structure is synchronized, and the time difference is within the set acceptable error range; the gate control signals of all insulated gate bipolar transistors on the same sub-conductor are the same.

[0032] In some embodiments, the fully solid-state power unit includes a first insulated gate bipolar transistor IGBT1, a second insulated gate bipolar transistor IGBT2, a first diode D1, and a second diode D2; the emitters of the first insulated gate bipolar transistor IGBT1 and the second insulated gate bipolar transistor IGBT2 are commonly connected, the cathode of the first diode D1 is connected to the collector of the first insulated gate bipolar transistor IGBT1, and the cathode of the second diode D2 is connected to the collector of the second insulated gate bipolar transistor IGBT2 to form an anti-parallel bi-directional conduction structure; the gates of the first insulated gate bipolar transistor IGBT1 and the second insulated gate bipolar transistor IGBT2 are respectively independently connected to the control and drive unit.

[0033] In some embodiments, in the RCD voltage limiting module: the resistor R and the diode D are connected in parallel to form a parallel structure, and the diode cathode side port of this parallel structure is connected in series with the capacitor C; the resistor is used to limit the over-voltage amplitude, the capacitor is used to absorb transient energy and control the voltage rise rate, and the diode provides a capacitor discharge path.

[0034] In some embodiments, the overvoltage protection device is a metal oxide varistor (MOV), and its rated operating voltage satisfies: being higher than the normal operating voltage of the all-solid-state power unit and lower than its maximum withstand voltage, and is used to absorb transient overvoltage energy.

[0035] In some embodiments, in the multi-unit series-parallel structure: the number of series branches is determined by the voltage difference borne when the switch is off, so as to ensure that the voltage of a single all-solid-state power unit is within a safe range; the number of parallel branches is determined by the instantaneous maximum current in the ice melting state, so as to increase the current-carrying capacity of the system.

[0036] In a preferred embodiment, the voltage difference is calculated according to the following formula: ;

[0037] Wherein, is the voltage difference at the short-circuit point on the current-carrying conductor and the distance to the short-circuit point , is the phase current of the current-carrying conductor, is the distance to the short-circuit point, is the resistance per unit length of the sub-conductor, is the inductance of the sub-conductor in the case of one current-carrying and one current-breaking.

[0038] In a preferred embodiment, the parameters of the RCD voltage-limiting module satisfy the following formula: ; Wherein, C is the capacitance value, is the stray inductance in the IGBT turn-off loop; The resistance R should be taken to satisfy the following formula: ; Wherein, is the maximum value of the collector current of the IGBT.

[0039] In a preferred embodiment, the actual number of the series-parallel branches is a 1.5-fold redundant configuration of the calculated number.

[0040] In some embodiments, the multi-unit series-parallel structure further includes: a buffer impedance element connecting each all-solid-state power unit, which is used to suppress the circulating current and oscillation between units.

[0041] The specific embodiments of the present invention are further described below.

[0042] An all-solid-state breaking structure for a live-line ice melting device for bundled conductors includes: a multi-unit series-parallel structure composed of a plurality of all-solid-state power units and a control and drive unit.

[0043] Such as Figure 1As shown, the all-solid-state power unit includes an insulated gate bipolar transistor (IGBT) connected in common emitter and an antiparallel diode; the insulated gate bipolar transistor in common emitter has a bidirectional conduction function, and the series-parallel structure composed of this unit should have two ports, which are respectively connected to the jumper connection points of the two split conductors on the tower.

[0044] The first insulated gate bipolar transistor IGBT1 and the second insulated gate bipolar transistor IGBT2, the first diode D1 and the second diode D2; the emitter of the first insulated gate bipolar transistor IGBT1 is connected to the emitter of the second insulated gate bipolar transistor IGBT2, the cathode of the first diode D1 is connected to the collector of the first insulated gate bipolar transistor IGBT1, and the cathode of the second diode D2 is connected to the collector of the second insulated gate bipolar transistor IGBT2 to form an antiparallel structure; the gates of the first insulated gate bipolar transistor and the second insulated gate bipolar transistor are respectively connected to the control drive unit for independently receiving control signals with the same timing; the antiparallel structure can realize the functions of bidirectional current conduction and blocking, and is suitable for the opening and closing operations of AC circuits.

[0045] In this embodiment, the high-voltage transmission line and the corresponding rated sub-conductor current-carrying have a great influence on the voltage difference at the switch, which helps to determine the parameters and selection of the insulated gate bipolar transistor IGBT.

[0046] Among them, taking the two-split conductor as an example, the voltage difference between the two sub-conductors and the voltage difference at both ends of the break point of the disconnected conductor are calculated for the case where one of the two sub-conductors is disconnected and the other is turned on; according to Ohm's law, the voltage difference at the position from the short-circuit point to the position x away from the short-circuit point on the current-carrying sub-conductor is calculated as follows:

[0047] Among them, is the voltage difference at the position from the short-circuit point to the distance on the current-carrying sub-conductor, is the phase current of the current-carrying sub-conductor, is the distance to the short-circuit point, is the resistance per unit length of the sub-conductor, is the inductance of the sub-conductor in the case of one current-carrying and one current-breaking.

[0048] Furthermore, when the grid frequency is 50Hz, it can be determined that:

[0049] Among them, .

[0050] Furthermore, steel-cored aluminum stranded wires are mostly used in high-voltage transmission lines, and the corresponding resistance per unit length can be obtained according to the type of steel-cored aluminum stranded wire used. and inductance parameters; the current of the transmission line needs to be determined according to the actual situation. Taking 110 kV as an example, the current level of the transmission line can be between 600 - 1200 A; if the resistance and inductance parameters of the commonly used steel-cored aluminum stranded wire of the 110 kV line are adopted, the distance from the short-circuit point is taken as 10 km to 20 km for calculation, and the voltage difference between the short-circuit point and the position x from the short-circuit point on the energized conductor can reach between 3 kV and 10 kV.

[0051] Furthermore, when calculating the voltage difference between the two ends of the broken port of the sub-conductor of the high-voltage transmission line, the method is the same as the above method; for the energized conductor, the voltage at the short-circuit point is , and the voltage at the position x from the short-circuit point is ; for the disconnected sub-conductor, the voltage on one side is the same as that at the short-circuit point, and the voltage on the other side is the same as the voltage at the position x from the short-circuit point (because there is a short-circuit point in the ice melting device), so the voltage difference between the two ends of the conductor port is the same as the line-to-line voltage difference of the above-mentioned bundled conductor which is the same, in the range of 3 kV - 10 kV. Therefore, the insulated gate bipolar transistor IGBT described in the patent should select a model that can carry a large voltage and a large current to reduce the number of device uses and reduce the mechanical and electrical complexity of the overall switching structure.

[0052] Such as Figure 2 shown, the RCD voltage-limiting circuit composed of the resistor R, capacitor C and diode D is connected in parallel with the corresponding insulated gate bipolar transistor; among them, the resistor R is connected in parallel with the diode D. In the composed parallel structure, the parallel port on the cathode side of the diode D is connected to the capacitor C, that is, the parallel structure composed of the resistor R and the diode D is connected in series with the capacitor C to form a complete voltage-limiting module; the resistor R is used to limit the overvoltage amplitude during the opening process, the capacitor C is used to absorb the transient energy during the opening process and control the voltage rise rate, and the diode D is used to provide a unidirectional conduction path to ensure capacitor discharge; the impedance parameters of the voltage-limiting circuit match the parasitic parameters of the insulated gate bipolar transistor to ensure uniform voltage distribution in the multi-unit structure and improve the voltage withstand capacity and reliability of the system; the RCD module of the voltage-limiting circuit should be connected in parallel at both ends of each unit, and the number of RCD modules should be exactly the same as the number of anti-parallel power modules.

[0053] Among them, the parameter selection methods of the resistor R and capacitor C of the voltage-limiting RCD module are as follows: The energy on the stray inductance at the moment of turn-off needs to be completely transferred to the capacitor C, and there is:

[0054] Among them is the stray inductance in the IGBT circuit breaker, which can be obtained by organizing the empirical formula:

[0055] In this embodiment, the opening and closing structure is in a normally open or normally closed state, and the influence of C discharging through R does not need to be considered. Therefore, a relatively large capacitance C value can be appropriately selected; the opening and closing structure described in this patent should also fully consider the heat dissipation of the on-line ice melting device. When a large capacitance discharges, the current amplitude borne by the resistor R can be made smaller, reducing the power of R, thereby reducing the overall structure size and current heat generation, and effectively reducing the heat dissipation pressure of the overall device; the discharge current of the capacitor C should be limited to 25% of the maximum IGBT collector current Inside, so the value of the resistor R should satisfy the following formula:

[0056] Furthermore, a metal oxide varistor (MOV) overvoltage protection device, the metal oxide varistor is connected in parallel at both ends of each all-solid-state power unit; the rated working voltage of the metal oxide varistor is higher than the normal working voltage of the all-solid-state power unit and lower than the maximum withstand voltage value of the all-solid-state power unit; when a transient overvoltage appears in the system, the metal oxide varistor conducts to absorb the excess energy and limits the voltage amplitude at both ends of the all-solid-state power unit.

[0057] Such as Figure 3 shown, the multi-unit series-parallel structure includes: multiple all-solid-state power units are connected in series to form multiple series branches, and the multiple series branches are connected in parallel to form a complete opening and closing unit; the number of all-solid-state power units in each series branch is determined according to the voltage difference in the switch-off scenario to ensure that the voltage borne by each all-solid-state power unit is within a safe range; the number of parallel branches is determined according to the instantaneous maximum current that can pass through the sub-conductor in the ice melting state to improve the current-carrying capacity of the system; Among them, considering that the insulated gate bipolar transistor IGBT has a high on-state loss when the current is large, so an IGBT with a larger withstand voltage and a higher maximum collector current should be selected as much as possible to reduce the number of series branches, thereby reducing the overall heat dissipation pressure of the ice melting device.

[0058] In this embodiment, redundancy also needs to be considered in the series-parallel structure. Since the open-circuit structure is applied to the main transmission line with a higher voltage level, the actual number of series-parallel branches that is 1.5 times the calculated number of series-parallel branches needs to be applied; each all-solid-state power unit in the multi-unit series-parallel structure realizes synchronous opening and closing through the control and drive unit to ensure uniform distribution of voltage and current.

[0059] Such asFigure 4 As shown, the all-solid-state breaking structure of the present invention can be applied to a four-split conductor system. In this embodiment, the all-solid-state breaking device is installed on one of the conductors of the four-split conductor. When ice melting operation is required, the control system issues an instruction, and the all-solid-state breaking structure performs the breaking operation according to a preset program, introducing the ice melting current into the remaining specified conductors while maintaining the normal power supply function of the remaining conductors, thus achieving the goal of ice melting without power interruption.

[0060] In this embodiment, the all-solid-state breaking structure applied to the on-line power interruption-free ice melting device for split conductors should be used as a breaking module and placed in the ice melting device. The ideal installation position of the ice melting device is at the conductor connection part of the transmission tower. At this installation position, the control unit of the all-solid-state breaking structure adopts a sealed waterproof design and can adapt to various harsh climate conditions. The control unit maintains real-time data exchange with the ground monitoring center through an optical fiber communication system, can remotely monitor the operation status of the device and receive control instructions. When the meteorological monitoring system detects the risk of icing, the control center issues an ice melting instruction. The all-solid-state breaking structure first performs the operation of disconnecting the specified sub-conductor, and then the ice melting current surges into the remaining sub-conductors. During the whole process, the power grid users cannot perceive the power supply interruption, achieving the "ice melting without power interruption" in the true sense.

[0061] In summary, the present invention proposes an all-solid-state breaking structure for an on-line power interruption-free ice melting device for split conductors. This structure uses all-solid-state IGBTs as the core power electronic devices, constructs the breaker unit through an anti-parallel topology, and uses a passive RCD circuit to achieve the voltage limiting function. The present invention designs a multi-unit series-parallel configuration scheme, effectively improving the voltage withstand capacity and current-carrying capacity of the system and adapting to the voltage and current requirements of high-voltage lines. This breaking structure has the advantages of fast response speed, high reliability, good electromagnetic compatibility, etc., and can achieve the ice melting operation of high-voltage lines without interrupting power supply, solving the technical problem that traditional ice melting methods require power interruption. The all-solid-state breaking structure of the present invention replaces the mechanical switch, eliminates the aging of mechanical components and the hidden danger of electric arcs, avoids the potential breaking faults of the mechanical switch in extreme environments such as cold and humid, and at the same time the optimized anti-parallel topology and RCD voltage limiting circuit design ensure the stable operation of the system in a high-voltage environment. The solution of the present invention is of great significance for improving the operation reliability of the power grid under harsh climate conditions.

[0062] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several alternatives or modifications can be made to these described embodiments, and these alternative or modified forms should all be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description with reference to the terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of protection of the patent application.

Claims

1. A fully solid-state breaking structure for an on-line power-off ice melting device of bundled conductors, characterized in that, Including: A series of multi-unit series-parallel structures, each multi-unit series-parallel structure is correspondingly configured with one sub-conductor in the bundled conductor. In each multi-unit series-parallel structure, multiple all-solid-state power units are connected in series to form multiple series branches, and the multiple series branches are connected in parallel; Among them, the all-solid-state power unit includes: An anti-parallel topology composed of a pair of insulated gate bipolar transistors (IGBTs) connected in common-emitter and anti-parallel diodes to achieve bi-directional current conduction and blocking; A voltage-limiting circuit, which consists of a resistor (R), a capacitor (C) and a diode (D) to form an RCD voltage-limiting module, and is connected in parallel across each insulated gate bipolar transistor; An over-voltage protection device, which is connected in parallel across each insulated gate bipolar transistor; A control and drive unit, which is electrically connected to the gates of the insulated gate bipolar transistors. Each all-solid-state power unit in the multi-unit series-parallel structure realizes synchronous turn-on and turn-off through the control of the control and drive unit; Among them, the two ports of each multi-unit series-parallel structure are respectively connected to the jumper strings of two sections of bundled conductors at the transmission tower.

2. The all-solid-state breaking structure according to claim 1, wherein The all-solid-state power unit includes a first insulated gate bipolar transistor (IGBT1), a second insulated gate bipolar transistor (IGBT2), a first diode (D1) and a second diode (D2); The emitters of the first insulated gate bipolar transistor (IGBT1) and the second insulated gate bipolar transistor (IGBT2) are commonly connected. The cathode of the first diode (D1) is connected to the collector of the first insulated gate bipolar transistor (IGBT1), and the cathode of the second diode (D2) is connected to the collector of the second insulated gate bipolar transistor (IGBT2), forming an anti-parallel bi-directional conduction structure; The gates of the first insulated gate bipolar transistor (IGBT1) and the second insulated gate bipolar transistor (IGBT2) are respectively and independently connected to the control and drive unit.

3. The all-solid-state breaking structure according to claim 1, characterized in that, In the RCD voltage-limiting module: The resistor (R) and the diode (D) are connected in parallel to form a parallel structure, and the cathode-side port of the parallel structure is connected in series with the capacitor (C); The resistor is used to limit the over-voltage amplitude, the capacitor is used to absorb transient energy and control the voltage rise rate, and the diode provides a discharge path for the capacitor.

4. The all-solid-state breaking structure according to claim 1, wherein The over-voltage protection device is a metal oxide varistor (MOV), and its rated operating voltage satisfies: Higher than the normal operating voltage of the all-solid-state power unit and lower than its maximum withstand voltage, and is used to absorb transient over-voltage energy.

5. The all-solid-state breaking structure according to claim 1, characterized in that In the multi-unit series-parallel structure: The number of series branches is determined by the voltage difference borne when the switch is off to ensure that the voltage of a single all-solid-state power unit is within a safe range; The number of parallel branches is determined by the instantaneous maximum current in the ice-melting state to increase the current-carrying capacity of the system.

6. The all-solid-state breaking structure according to claim 5, wherein The calculation of the voltage difference is based on the following formula: ； Wherein, is the voltage difference at the short - circuit point on the current - carrying sub - wire and the distance to the short - circuit point, is the phase current of the current - carrying sub - wire, is the distance to the short - circuit point, is the resistance per unit length of the sub - wire, is the inductance of the sub - wire under the condition of one current - carrying and one current - interrupted. ​ 7. The all-solid-state breaking structure according to claim 6, characterized in that, The parameters of the RCD voltage-limiting module satisfy the following formula: ； where C is the capacitance value, is the stray inductance in the IGBT turn-off circuit, The value of the resistor R should satisfy the following formula: ； Among them, is the maximum value of the collector current of the IGBT.

8. The all-solid-state breaking structure according to claim 5, wherein The actual number of series and parallel branches of the multi-unit series-parallel structure is configured with a 1.5-fold redundancy of the calculated number.

9. The all-solid-state breaking structure according to any one of claims 1 to 8, characterized in that, The multi-unit series-parallel structure further includes: A buffer impedance element connecting each all-solid-state power unit, which is used to suppress the circulating current and oscillation between units.

10. The all-solid-state breaking structure according to any one of claims 1 to 8, characterized in that The control and drive unit satisfies the following: The gate control signals output to the gates of the insulated gate bipolar transistors in the multi-unit series-parallel structure are timing-synchronized, and the time difference is within the set acceptable error range; The gate control signals of all the insulated gate bipolar transistors on the same sub-wire are the same.

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