CN112927978B - A circuit breaker dynamic capacitor voltage equalization device and method - Google Patents

Abstract

The application provides a dynamic capacitance voltage equalizing device and a method of a circuit breaker, wherein the voltage equalizing device comprises a voltage equalizing component and a control component; the voltage equalizing assembly comprises a capacitor bank and an electronic switch bank which are connected with each other; the capacitor bank comprises a plurality of voltage-sharing capacitors, and the voltage-sharing capacitors are connected with one another; the control assembly comprises a voltage divider and a controller; one end of the controller is connected with the voltage divider, and the other end of the controller is connected with the electronic switch group. The voltage equalizing component is connected with the fracture of each vacuum arc extinguishing chamber in parallel, so that the problem of uneven voltage division of the multi-fracture vacuum circuit breaker can be effectively solved, the breaking capacity of the multi-fracture vacuum circuit breaker is improved, and the application of the vacuum circuit breaker at higher voltage level is realized. The dynamic voltage equalizing problem in the opening process of the multi-fracture serial vacuum circuit breaker is effectively solved, the short-circuit current opening capacity is improved, and the serial reliable operation of a plurality of vacuum arc-extinguishing chambers is realized.

Description

A circuit breaker dynamic capacitor voltage equalization device and method

technical field

The present application relates to the technical field of vacuum circuit breakers, in particular to a dynamic capacitor voltage equalization device and method for a circuit breaker.

Background technique

Circuit breakers are important control and protection equipment in power systems. Vacuum and SF ₆ are two widely used insulating and arc-extinguishing media in circuit breakers. SF ₆ gas has excellent thermochemical properties and strong electronegative properties, and its insulation and arc extinguishing properties are more suitable for the requirements of high voltage levels. Currently, it occupies a dominant position in circuit breakers with voltage levels of 72.5-1000kV in China. However, SF ₆ gas can produce highly toxic decomposition products after arc pyrolysis, and it is also a greenhouse gas. Therefore, research on vacuum circuit breakers with higher voltage levels has become one of the important research directions in the field of high voltage switches at home and abroad. High-voltage vacuum circuit breakers are divided into high-voltage single-break vacuum circuit breakers and high-voltage multi-break vacuum circuit breakers. Among them, due to the saturation characteristics of the dielectric strength of the vacuum gap, the development of high-voltage single-break vacuum circuit breakers is relatively slow. The multi-fracture series connection technology can connect multiple vacuum short gaps in series, make full use of the excellent pressure resistance characteristics of the vacuum short gaps, and obtain higher pressure resistance performance.

However, the stray capacitance of the multi-break vacuum circuit breaker will lead to uneven distribution of the break voltage, and the degree of unevenness is closely related to the layout of each break, which will affect the electric field distribution inside the arc extinguishing chamber. Moreover, when the multi-fracture vacuum circuit breaker breaks the current, the difference in the arcing characteristics of each fracture will lead to the difference in the diffusion characteristics of the residual particles after the arc, which will lead to the difference in the equivalent impedance after the arc, and finally cause the transient recovery voltage distribution of each fracture to be different. uniform. The uneven distribution of voltage among the breaks usually means that the breaks with high transient recovery voltage are prone to re-ignition, which in turn leads to the re-ignition of the entire multi-break circuit breaker, which is extremely unfavorable to the breaking of the multi-break vacuum circuit breaker, and appropriate measures must be taken Voltage equalization measures to improve the uniformity of the voltage distribution of each fracture.

However, due to the significant difference between vacuum circuit breakers and SF ₆ circuit breakers in arc characteristics and after-arc dielectric strength recovery characteristics, the existing voltage equalizing capacitor devices cannot be directly used in multi-break vacuum circuit breakers. The research results show that the breaking capacity of the double-break vacuum circuit breaker does not increase monotonously with the increase of the voltage equalizing capacitance; The breaking capacity of the vacuum circuit breaker has a negative impact, and even if a suitable voltage equalizing capacitor is added, the voltage of the two fractures cannot be completely consistent when the circuit breaker actually breaks the current.

Contents of the invention

In order to solve the above problems, the present application provides a circuit breaker dynamic capacitor voltage equalization device and method to solve the problem of uneven voltage division during the breaking process of a multi-break vacuum circuit breaker.

In order to achieve the above object, the application realizes through the following technical solutions:

On the one hand, a dynamic capacitive voltage equalization device for a circuit breaker, including a voltage equalization component and a control component;

The voltage equalizing assembly includes interconnected capacitor banks and electronic switch banks;

The capacitor bank includes a plurality of voltage equalizing capacitors, and the plurality of voltage equalizing capacitors are connected to each other;

The control assembly includes a voltage divider and a controller;

One end of the controller is connected with the voltage divider, and the other end of the controller is connected with the electronic switch group.

Optionally, multiple voltage equalizing capacitors are connected in parallel;

The voltage equalizing capacitor includes a plurality of capacitors, and the plurality of capacitors are serially connected in series.

Optionally, the electronic switch group includes a plurality of switches;

the switches are connected in parallel with the capacitors, and the number of switches is the same as the number of capacitors;

The switch is also connected to the controller.

Optionally, multiple voltage equalizing capacitors are connected in series in sequence;

The voltage equalizing capacitor includes a plurality of capacitors, and the plurality of capacitors are connected in parallel with each other.

Optionally, the electronic switch group includes a plurality of switches;

The switches are connected in series with the capacitors, and the number of switches is the same as the number of capacitors;

The switch is also connected to the controller.

On the other hand, a dynamic capacitor voltage equalization method for a circuit breaker includes:

Connect the circuit breaker dynamic capacitor equalizing device with the vacuum circuit breaker;

Obtaining the first voltage value and the second voltage value obtained by the voltage divider monitoring the fracture of the vacuum circuit breaker;

The controller calculates the voltage difference between the first voltage value and the second voltage value according to the preset voltage equalization technology control program, and controls the electronic switch group according to the voltage difference until the voltage difference is less than the preset voltage threshold value.

It can be known from the above technical solutions that the embodiments of the present application provide a circuit breaker dynamic capacitor voltage equalization device and method, the voltage equalization device includes a voltage equalization component and a control component; the voltage equalization component includes interconnected capacitor banks and electronic A switch bank; the capacitor bank includes a plurality of voltage equalizing capacitors, and a plurality of the voltage equalizing capacitors are connected to each other; the control assembly includes a voltage divider and a controller; one end of the controller is connected to the voltage divider , the other end of the controller is connected to the electronic switch group. By connecting a set of equalizing components in parallel to the fractures of each vacuum interrupter, the uniformity of voltage distribution during the breaking process of the multi-fracture vacuum circuit breaker can be improved, and at the same time, the requirement of reducing the transient recovery voltage rise rate of each fracture can be taken into account, which can effectively Solve the problem of uneven voltage division of multi-fracture vacuum circuit breakers, improve the breaking capacity of multi-fracture vacuum circuit breakers, and realize the application of vacuum circuit breakers at higher voltage levels. Effectively solve the problem of dynamic voltage equalization during the breaking process of multi-fracture series vacuum circuit breakers, improve the breaking capacity of short-circuit current, and realize the reliable operation of multiple vacuum interrupters in series.

Description of drawings

In order to illustrate the technical solution of the present application more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, on the premise of not paying creative labor, Additional drawings can also be derived from these drawings.

Fig. 1 is a schematic structural diagram of a dynamic capacitive voltage equalizing device for a circuit breaker in an embodiment of the present application;

Fig. 2 is a schematic structural diagram of a pressure equalizing component in an embodiment of the present application;

FIG. 3 is a schematic structural diagram of another pressure equalizing component in an embodiment of the present application.

Among them, 1-voltage equalizing component, 11-capacitor bank, 111-voltage equalizing capacitor, 1111-capacitor, 12-electronic switch group, 121-switch, 2-control component, 21-voltage divider, 22-controller, 3 - Vacuum interrupter.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by this application easy to understand, the following will further elaborate this application in conjunction with specific implementation methods.

Fig. 1 is a schematic structural diagram of a dynamic capacitive voltage equalization device for a circuit breaker in an embodiment of the present application. Referring to Fig. 1, an embodiment of the present application provides a dynamic capacitive voltage equalization device for a circuit breaker, including a voltage equalizing component 1 and a control component 2; The pressure equalizing assembly 1 plays a role of equalizing pressure, improving the breaking performance of the vacuum circuit breaker. The voltage equalizing component 1 includes a capacitor bank 11 and an electronic switch bank 12 connected to each other; the capacitor bank 11 includes a plurality of voltage equalizing capacitors 111, and a plurality of the voltage equalizing capacitors 111 are connected to each other; the control component 2 includes a branch A voltage regulator 21 and a controller 22; one end of the controller 22 is connected to the voltage divider 21, and the other end of the controller 22 is connected to the electronic switch group 12.

The voltage divider 21 is used to monitor the voltage at the port, and transmits the voltage value to the controller 22 , and the controller 22 is used to control the electronic switch group 12 . The pressure equalizing device provided in this application is not only suitable for double-break vacuum circuit breakers, but also suitable for multi-break vacuum circuit breakers.

The multi-fracture high-voltage vacuum circuit breaker adopts a multi-fracture series structure, that is, in the ABC three-phase, each phase is composed of two or more vacuum interrupters connected in series. The rated voltage of the vacuum interrupters used in series and the number of vacuum interrupters connected in series for each phase are selected according to the rated voltage of the multi-break high-voltage vacuum circuit breaker. As shown in Figure 1, any phase in the vacuum circuit breaker is composed of two vacuum interrupters 3 connected in series, and each vacuum interrupter 3 is connected with a pressure equalizing component 1 in parallel at both ends of the vacuum interrupter 3, and the rated parameters of the vacuum interrupter 3 are 40.5kV, 2500A-40kA, two vacuum interrupters 3 form a 75kV, 2500A-40kA double-break vacuum circuit breaker.

There are multiple combinations of the multiple voltage equalizing capacitors 111 in the capacitor bank 11 to obtain multiple different capacitance values. The two ends of the vacuum interrupter 3 are also connected in parallel with a voltage divider 21, the voltage divider 21 is used to monitor the voltage at both ends of the vacuum interrupter 3, and the monitored voltages of the two fractures, namely the first voltage value and the second voltage The value is transmitted to the controller 22, and the controller 22 calculates the voltage difference between the first voltage value and the second voltage value according to the preset voltage equalization technology control program, and controls different electronic switch groups according to the calculated voltage difference 12, and then connect the voltage equalizing capacitors 111 with different capacitance values, so as to control the voltage difference between the two fractures of the vacuum interrupter 3 to be smaller than the preset voltage critical value.

In some embodiments, FIG. 2 is a schematic structural diagram of a voltage equalizing component in an embodiment of the present application. As shown in FIG. 2 , a plurality of the voltage equalizing capacitors 111 are connected in parallel; the voltage equalizing capacitor 111 includes a plurality of capacitors 1111, a plurality of capacitors 1111 are connected in series in sequence, and then combined into voltage equalizing capacitors 111 with different capacitances. Wherein, the number of capacitors 1111 may be ten, and the capacitance value is 1000 pF, which is not specifically limited in this embodiment. The electronic switch group 12 includes a plurality of switches 121; the switches 121 are connected in parallel with the capacitors 1111, and the number of the switches 121 is the same as the number of the capacitors 1111; the switches 121 are also connected to the controller 22 connected.

In some embodiments, FIG. 3 is a schematic structural diagram of another voltage equalizing component in the embodiment of the present application. As shown in FIG. 3 , a plurality of the voltage equalizing capacitors 111 are connected in series; A capacitor 1111 , a plurality of capacitors 1111 are connected in parallel to form voltage equalizing capacitors 111 with different capacitances. Wherein, the number of capacitors 1111 may be ten, and the capacitance value is 1000 pF, which is not specifically limited in this embodiment. The electronic switch group 12 includes a plurality of switches 121; the switches 121 are connected in series with the capacitors 1111, and the number of the switches 121 is the same as the number of the capacitors 1111; the switches 121 are also connected to the controller 22 connected.

The on and off of the switch 121 is controlled by the controller 22, so that the capacitors 1111 are combined into voltage equalizing capacitors 111 with different capacitances, which are suitable for multi-type multi-break high-voltage vacuum circuit breakers. For example, it is suitable for a three-break 126kV vacuum circuit breaker composed of three 40.5kV vacuum interrupters in series for each phase, or a six-break 252kV vacuum circuit breaker for each phase composed of six 40.5kV vacuum interrupters in series; The phase is a double-break 126kV vacuum circuit breaker composed of two 72.5kV vacuum interrupters in series; it is suitable for a double-break 252kV vacuum circuit breaker composed of two 126kV vacuum interrupters in series, or each phase is composed of six 126kV vacuum The six-break 750kV vacuum circuit breaker formed by series connection of arc extinguishing chambers is not specifically limited in this embodiment. Compared with the dual-break series operation mode of simple parallel voltage equalizing capacitors in the prior art, the variable voltage equalizing capacitor branch current limiting in this application can effectively reduce the voltage non-uniformity of the double breaks during the breaking process and improve the breaking performance and reliability.

On the other hand, the embodiment of the present application also provides a dynamic capacitor voltage equalization method for a circuit breaker, including:

Connect the circuit breaker dynamic capacitor equalizing device with the vacuum circuit breaker;

Obtaining the first voltage value and the second voltage value obtained by the voltage divider monitoring the fracture of the vacuum circuit breaker;

The controller calculates the voltage difference between the first voltage value and the second voltage value according to the preset voltage equalization technology control program, and controls the electronic switch group according to the voltage difference until the voltage difference is less than the preset voltage threshold value.

It can be known from the above technical solutions that the embodiment of the present application provides a circuit breaker dynamic capacitor voltage equalization device and method, the voltage equalization device includes a voltage equalization component 1 and a control component 2; the voltage equalization component 1 includes interconnected capacitors group 11 and an electronic switch group 12; the capacitor group 11 includes a plurality of voltage equalizing capacitors 111, and a plurality of the voltage equalizing capacitors 111 are connected to each other; the control assembly 2 includes a voltage divider 21 and a controller 22; the control One end of the controller 22 is connected to the voltage divider 21 , and the other end of the controller 22 is connected to the electronic switch group 12 . By connecting a set of equalizing components in parallel to the fractures of each vacuum interrupter, the uniformity of voltage distribution during the breaking process of the multi-fracture vacuum circuit breaker can be improved, and at the same time, the requirement of reducing the transient recovery voltage rise rate of each fracture can be taken into account, which can effectively Solve the problem of uneven voltage division of multi-fracture vacuum circuit breakers, improve the breaking capacity of multi-fracture vacuum circuit breakers, and realize the application of vacuum circuit breakers at higher voltage levels. Effectively solve the problem of dynamic voltage equalization during the breaking process of multi-fracture series vacuum circuit breakers, improve the breaking capacity of short-circuit current, and realize the reliable operation of multiple vacuum interrupters in series.

The basic principles and main features of the application and the advantages of the application have been shown and described above. For those skilled in the art, it is obvious that the application is not limited to the details of the above-mentioned exemplary embodiments, and without departing from the spirit or fundamentals of the application. In the case of features, the present application can be implemented in other specific forms. Therefore, the embodiments should be regarded as exemplary and not restrictive in all points of view, and the scope of the application is defined by the appended claims rather than the foregoing description, and it is intended that the scope of the present application be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in this application.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only includes an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

The similar parts between the embodiments provided in the present application can be referred to each other, and the specific implementations provided above are only a few examples under the general concept of the present application, and do not constitute a limitation of the protection scope of the present application. For those skilled in the art, any other implementations expanded based on the proposal of the present application without creative work shall fall within the scope of protection of the present application.

Claims (2)

1. A circuit breaker dynamic capacitance equalizing device, characterized in that it comprises a equalizing assembly (1) and a control assembly (2); The voltage equalizing assembly (1) includes a capacitor bank (11) and an electronic switch bank (12) connected to each other; The capacitor bank (11) includes a plurality of voltage equalizing capacitors (111), and the plurality of voltage equalizing capacitors (111) are connected to each other; The control assembly (2) includes a voltage divider (21) and a controller (22); One end of the controller (22) is connected to the voltage divider (21), and the other end of the controller (22) is connected to the electronic switch group (12); The voltage equalizing capacitor (111) includes a plurality of capacitors (1111), and the electronic switching group (12) includes a plurality of switches (121); Wherein, the connection mode of the capacitor (1111) and the switch (121) is: a plurality of the capacitors (1111) are serially connected in series; the switch (121) is connected in parallel with the capacitor (1111), and the switch The number of (121) is the same as the number of the capacitors (1111); the switch (121) is also connected to the controller (22); Or the connection mode of the capacitor (1111) and the switch (121) is that multiple capacitors (1111) are connected in parallel; the switch (121) is connected in series with the capacitor (1111), and the switch (121 ) is the same as the capacitor (1111); the switch (121) is also connected to the controller (22). 2. A circuit breaker dynamic capacitance equalization method, characterized in that, comprising: Connecting the circuit breaker dynamic capacitance equalizing device to the vacuum circuit breaker; wherein, the circuit breaker dynamic capacitive equalizing device includes a equalizing component and a control component; The voltage equalizing assembly includes interconnected capacitor banks and electronic switch banks; The capacitor bank includes a plurality of voltage equalizing capacitors, and the plurality of voltage equalizing capacitors are connected to each other; The control assembly includes a voltage divider and a controller; one end of the controller is connected to the voltage divider, and the other end of the controller is connected to the electronic switch group; The voltage equalizing capacitor includes a plurality of capacitors, and the electronic switch group includes a plurality of switches; Wherein, the connection mode of the capacitor and the switch is: a plurality of the capacitors are connected in series; the switch is connected in parallel with the capacitor, and the number of the switch is the same as the number of the capacitor; the switch is also connected with the capacitor. the controller is connected; Or the connection mode of the capacitor and the switch is: a plurality of the capacitors are connected in parallel; the switch is connected in series with the capacitor, and the number of the switch is the same as the number of the capacitor; the switch is also connected to the capacitor connected to the controller; Obtaining the first voltage value and the second voltage value obtained by the voltage divider monitoring the fracture of the vacuum circuit breaker; The controller calculates the voltage difference between the first voltage value and the second voltage value according to the preset voltage equalization technology control program, and controls the electronic switch group according to the voltage difference until the voltage difference is less than the preset voltage threshold value.

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