CN111509689B - A ground fault full compensation system and method for multiplexing parallel reactive power compensation - Google Patents

Abstract

In the ground fault full-compensation system and method for multiplexing parallel reactive compensation, the system is composed of a phase power supply converter, a multiplexing compensation device, a ground fault compensation switch, an injection transformer and a multiplexing controller, the multiplexing controller judges whether the system is in a normal operation state or a single-phase ground fault state according to collected signals, when the power system is in the normal operation state, the ground fault compensation switch is switched off, and the multiplexing compensation device performs reactive power compensation on the power system; when the single-phase earth fault occurs in the power system, the earth fault compensation switch is closed, the multiplexing compensation device stops reactive compensation, and the multiplexing compensation device and/or the injection transformer are/is adjusted to perform single-phase earth fault full compensation; the system performs reactive power compensation when the power system normally operates, performs earth fault current full compensation when the system has single-phase earth fault, works in a full life cycle, and improves the utilization rate of the single-phase earth compensation device.

Description

A ground fault full compensation system and method for multiplexing parallel reactive power compensation

technical field

The present application relates to the technical field of power systems, in particular to a ground fault full compensation system and method for multiplexing parallel reactive power compensation.

Background technique

Single-phase ground faults in distribution networks at home and abroad account for more than 80%, which seriously affects the safe operation of power grids and equipment. Safe handling of ground faults plays an important role in social and economic development. When the capacitive current of the system is greater than 10A, the arc suppressing coil is grounded. The arc suppressing coil can reduce the fault current to a certain extent, and the system can run for 2 hours with a fault, but the arc suppressing coil cannot realize full compensation, and there is still a residual current of less than 10A at the fault point, which can cause personal electric shock and fire accidents , and seriously threaten the safe and stable operation of the power grid and equipment. When the capacitive current of the system is large, a small resistance grounding method is often used. When a single-phase grounding fault occurs, the zero-sequence current of the faulty line is amplified, and the relay protection device quickly cuts off the faulty line. However, the power supply reliability of this grounding method is difficult to guarantee. , and there is a risk of relay protection refusing to operate when there is a high-impedance grounding.

At present, in order to completely eliminate the single-phase ground fault hazard, while ensuring the reliability of power supply. Many methods for fully compensating single-phase ground fault point current have been proposed at home and abroad. It mainly includes: on the one hand, the GFN (ground fault neutralizer) manufactured by Swedish Neutral in Sweden is used to realize the full compensation of ground fault by using the power electronic active power supply; ) technical principle also belongs to active full compensation. On the other hand, the inventor proposed a patent for a ground fault current compensation system and method for a self-produced power supply phase power supply. Using a phase power supply converter, since there is no power electronic power supply, it has significant advantages in terms of cost and stability. Advantage.

However, the normal operation time of the power system is far longer than the duration of a single-phase ground fault. Whether it is arc suppressing coil, active ground fault full compensation or self-generated power supply full ground fault compensation, in most of its operation During the normal operation of the system, there is no contribution during the normal operation of the system; the value of the single-phase grounding compensation device is high, if it is in the "idle" state most of the time, the single-phase grounding compensation device is not fully utilized, which is a serious problem for the equipment resources of the power system. waste.

Contents of the invention

The present application provides a ground fault full compensation system and method for multiplexing parallel reactive power compensation to solve the technical problem of low utilization rate of single-phase ground fault compensation devices.

In order to solve the above technical problems, the embodiment of the present application discloses the following technical solutions:

In the first aspect, the present application provides a multiplexed parallel reactive power compensation ground fault full compensation system, the system includes a phase power supply converter, a multiplexed compensation device, a grounded fault compensation switch, an injection transformer, and a multiplexed controller ,in:

One side of the phase power supply converter is connected to the power system bus, and the other side is connected to the multiplexing compensation device;

The multiplexing compensation device is grounded, and one end of the multiplexing compensation device is connected to the phase power supply converter, and the other end is connected to the ground fault compensation switch;

One end of the ground fault compensation switch is connected to the multiplexing compensation device, and the other end is connected to the injection transformer;

The other end of the injection transformer is respectively connected to the neutral point and ground of the power system;

The multiplexing controller is connected with the multiplexing compensation device, the ground fault compensation switch and the injection transformer.

Optionally, the system includes a phase power converter, a multiplexing compensation device, a ground fault compensation switch, and a multiplexing controller, wherein:

One side of the phase power supply converter is connected to the power system bus, and the other side is connected to the multiplexing compensation device;

One end of the multiplexing compensation device is connected to the phase power supply converter, and the other end is connected to the ground fault compensation switch;

One end of the ground fault compensation switch is connected to the multiplexing compensation device, and the other end is connected to the neutral point of the power system;

The multiplexing controller is connected to the multiplexing compensation device and the ground fault compensation switch).

Optionally, the multiplexing controller includes:

The system signal acquisition module is used to collect the bus voltage, bus load current, line current, multiplexing compensation device voltage, and multiplexing compensation device current signal of the power system;

The system state judgment and switching module is used to judge that the power system is in a normal operation state or a single-phase ground fault state according to the signal collected by the system signal collection module, and control the ground fault compensation switch;

A reactive power compensation control module, configured to control the multiplexing compensation device to output the reactive power output required by the power system according to the signal collected by the system signal collection module;

The ground fault full compensation control module is used to control the transformation ratio of the injected transformer according to the signal collected by the system signal collection module to adjust the compensation voltage and compensation current when the single phase is grounded.

Optionally, the multiplexing controller further includes a protection module, which is used for isolating system faults when faults such as short circuit and overload occur.

Optionally, the phase power supply converter is a transformer or a combination of transformers;

The phase power supply converter is used to provide a reactive power compensation channel isolated from the power system;

The phase power supply converter is also used to transform the system line voltage into a phase voltage opposite to the system phase power supply as a compensation power supply with full compensation for single-phase grounding.

Optionally, the multiplexing compensation device adopts a star connection mode.

Optionally, the ground fault compensation switch is a combination of three single-phase switches.

Optionally, the injection transformer is a single-phase transformer with adjustable ratio.

Optionally, the neutral point of the power system is a system neutral point derived from a grounding transformer, a system neutral point derived from a main transformer of a power system, or a system neutral point derived from the phase power supply converter.

In the second aspect, the present application also provides a ground fault full compensation method for multiplexing parallel reactive power compensation, the method comprising:

Judging the operating status of the system;

When no single-phase ground fault occurs in the power system, the ground fault compensation switch is turned off, and the multiplexing compensation device performs reactive power compensation to the power system;

When a single-phase ground fault occurs in the power system, the ground phase is determined, the ground corresponding switch of the ground fault compensation switch is closed, and the multiplexing compensation device and/or injection transformer are adjusted to perform full single-phase ground fault compensation;

Judging whether the single-phase ground fault disappears, if so, disconnect the ground fault compensation switch, and the multiplexing compensation device performs reactive power compensation for the power system, if not, continue to perform full single-phase ground fault compensation.

Compared with the prior art, the beneficial effects of the present application are:

It can be seen from the above technical solutions that in the ground fault full compensation system and method for multiplexing parallel reactive power compensation provided by this application, the system consists of phase power supply converters, multiplexing compensation devices, ground fault compensation switches, injection transformers, and multiplexing control The multiplexing controller judges whether the system is in the normal operation state or the single-phase ground fault state according to the collected signal. When the power system is in the normal operation state, the ground fault compensation switch is turned off, and the multiplexing compensation device performs Reactive power compensation; when a single-phase ground fault occurs in the power system, determine the ground phase, the ground corresponding switch of the ground fault compensation switch is closed, adjust the multiplexing compensation device and/or inject the transformer to perform full compensation for single-phase ground fault; this system Reactive power compensation is performed during normal operation of the power system, and full ground fault current compensation is performed when a single-phase ground fault occurs in the system, working in a full life cycle to improve the utilization rate of single-phase ground fault compensation devices.

The ground fault full compensation system and method of multiplexing parallel reactive power compensation provided by this application improve the utilization rate of the ground fault full compensation device, realize the full life cycle operation of the device, and increase the value of power system assets; intensive multiplexing parallel Compared with the current two systems of reactive power compensation and single-phase grounding full compensation system, the ground fault full compensation system of reactive power compensation has a greatly reduced volume, convenient deployment and implementation, and low overall cost.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Description of drawings

In order to illustrate the technical solution of the present application more clearly, the accompanying drawings that need to be 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 work, there are also Additional figures can be derived from these figures.

Figure 1 is a schematic structural diagram of a ground fault full compensation system for multiplexing parallel reactive power compensation provided by an embodiment of the present application;

Fig. 2 is another schematic structural diagram of the ground fault full compensation system for multiplexing parallel reactive power compensation provided by the embodiment of the present application;

Fig. 3 is a structural schematic diagram of a multiplexed controller of a multiplexed parallel reactive power compensation ground fault full compensation system provided by an embodiment of the present application;

Figure 4 is one of the specific implementations of the multiplexed parallel reactive power compensation ground fault full compensation system provided by the embodiment of the present application;

Fig. 5 is the second specific implementation mode of the ground fault full compensation system for multiplexing parallel reactive power compensation provided by the embodiment of the present application;

Fig. 6 is the third specific implementation mode of the multiplexed parallel reactive power compensation ground fault full compensation system provided by the embodiment of the present application;

Fig. 7 is a schematic flow chart of a ground fault full compensation method for multiplexed parallel reactive power compensation provided by an embodiment of the present application.

Among them, 1-phase power supply converter, 2-multiplexing compensation device, 3-ground fault compensation switch, 4-injection transformer, 5-multiplexing controller, 51-system signal acquisition module, 52-system status judgment and switching Module, 53-reactive power compensation control module, 54-ground fault full compensation control module, 55-protection module.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described The embodiments are only some of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

This application provides a ground fault full compensation system for multiplexing parallel reactive power compensation, as shown in Figure 1, including a phase power supply converter 1, multiplexing compensation device 2, ground fault compensation switch 3, injection transformer 4, multiplexing Controller 5.

One side of the phase power supply converter 1 is connected to the busbar of the grid system, and the other side is connected to the multiplexing compensation device 2 and the ground fault compensation switch 3;

One end of the ground fault compensation switch 3 is connected to the multiplexing compensation device 2 and the phase power supply converter 1 , and the other end is connected to the injection transformer 4 . The other end of the injection transformer 4 is connected to the neutral point of the power system;

The multiplexing controller 5 is connected with the multiplexing compensation device 2, the ground fault compensation switch 3, and the injection transformer 4, and controls their actions.

Wherein, the injection transformer 4 is an optional module. When the injection transformer 4 is not selected, one end of the ground fault compensation switch 3 is connected to the multiplexing compensation device 2 and the phase power supply converter 1, and the other end is connected to the neutral point of the power system , the system is shown in Figure 2 at this time, specifically the system includes a phase power supply converter 1, a multiplexing compensation device 2, a ground fault compensation switch 3, and a multiplexing controller 5, wherein:

One side of the phase power supply converter 1 is connected to the power system bus, and the other side is connected to the multiplexing compensation device 2;

One end of the multiplexing compensation device 2 is connected to the phase power supply converter 1, and the other end is connected to the ground fault compensation switch 3;

One end of the ground fault compensation switch 3 is connected to the multiplexing compensation device 2, and the other end is connected to the neutral point of the power system;

The multiplexing controller 5 is connected with the multiplexing compensation device 2 and the ground fault compensation switch 3 .

As shown in FIG. 3 , the multiplexing controller 5 includes: a system signal acquisition module 51 , a system state judgment and switching module 52 , a reactive power compensation control module 53 , a ground fault full compensation control module 54 , and a protection module 55 .

The system signal acquisition module 51 collects signals such as bus voltage, bus load current, line current, multiplexing compensation device voltage, and multiplexing compensation device current of the power system; The signal judges that the power system is in a normal operating state or a single-phase ground fault state, and controls the ground fault compensation switch 3; the reactive power compensation control module 53 controls the multiplexing compensation device 2 to compensate power according to the signal collected by the system signal acquisition module 51 Reactive power and harmonics required by the system; the ground fault full compensation control module 54 controls the multiplexing compensation device 2 and/or injection transformer 4 according to the signal collected by the system signal acquisition module 51 to adjust the compensation voltage and compensation when single-phase grounding current. The protection module 55 judges the working state of the system according to the signal collected by the system signal acquisition module 51, and isolates the fault of the system when a fault such as a short circuit or overload occurs, so as to ensure that the fault of the system does not affect the normal operation of the power system.

The phase power supply converter 1 is a transformer or a combination of transformers, and the transformer can be an electromagnetic transformer or an electronic transformer or other types of transformers; the phase power supply converter 1 provides a reactive power compensation channel isolated from the power system; The phase-to-phase power supply converter 1 also converts the line voltage of the system into a phase voltage opposite to that of the phase power supply of the system, so as to provide a compensated power supply with full compensation for single-phase grounding. The capacity of the phase power supply converter 1 is: the maximum single-phase grounding compensation capacity of the target power system plus the maximum reactive power compensation capacity required by the target power system, with a margin of 10% to 50%.

The multiplexing compensation device 2 can be any structural form of reactive power compensation device, including but not limited to TCR, TCT, TSC, SVG, group switching capacitor bank and so on. The multiplexing compensation device 2 adopts a star connection mode in TCR mode, TCT mode, TSC mode, SVG mode, APF group switching capacitor bank mode, and its neutral point is grounded. The capacity of the multiplexing compensation device 2 is the maximum reactive power compensation capacity required by the target power system, and a margin of 10% to 50% is set.

The ground fault compensation switch 3 is a combination of three single-phase switches, one end of which is respectively connected to each phase of the phase power supply converter 1; when the injection transformer 4 is selected, the other end of the ground fault compensation switch 3 is short-circuited and connected to One side of the injection transformer 4; when the injection transformer 4 is not selected, the other end of the ground fault compensation switch 3 is short-circuited and connected to the neutral point of the system. The ground fault compensation switch 3 can be a mechanical switch, an electronic switch or other switches.

The injection transformer 4 is a single-phase transformer. The injection transformer 4 can be an electromagnetic transformer, a power electronic transformer or other transformers. The injection transformer 4 can be a voltage regulating transformer with an adjustable ratio or a transformer with a fixed ratio. The capacity of the injection transformer 4 is based on the maximum single-phase grounding compensation capacity of the target power system, and a margin of 10% to 50% is set.

The neutral point of the power system can be the system neutral point derived from the grounding transformer or the system neutral point derived from the main transformer of the power system, or the system neutral point derived from the phase power supply converter or other system neutral points.

In the second aspect, the present application also provides a ground fault full compensation method for multiplexing parallel reactive power compensation, as shown in Figure 7:

S110: judging the operating state of the system;

S120: When no single-phase ground fault occurs in the power system, the ground fault compensation switch is turned off, and the multiplexing compensation device performs reactive power compensation for the power system;

S130: When a single-phase ground fault occurs in the power system, determine the ground phase, close the ground corresponding switch of the ground fault compensation switch, adjust the multiplexing compensation device and/or inject the transformer to perform full compensation for the single-phase ground fault;

S140: judging whether the single-phase ground fault disappears;

S150: If yes, disconnect the ground fault compensation switch, and the multiplexing compensation device performs reactive power compensation to the power system;

S160: If not, continue to perform single-phase-to-ground fault full compensation.

It can be seen from the above technical solutions that in the ground fault full compensation system and method for multiplexing parallel reactive power compensation provided by this application, the system consists of phase power supply converters, multiplexing compensation devices, ground fault compensation switches, injection transformers, and multiplexing control The multiplexing controller judges whether the system is in the normal operation state or the single-phase ground fault state according to the collected signal. When the power system is in the normal operation state, the ground fault compensation switch is turned off, and the multiplexing compensation device performs Reactive power compensation; when a single-phase ground fault occurs in the power system, determine the ground phase, the ground corresponding switch of the ground fault compensation switch is closed, adjust the multiplexing compensation device and/or inject the transformer to perform full compensation for single-phase ground fault; this system Reactive power compensation is performed during normal operation of the power system, and full ground fault current compensation is performed when a single-phase ground fault occurs in the system, working in a full life cycle to improve the utilization rate of single-phase ground fault compensation devices.

As shown in Fig. 4, it is one of the specific implementations of a multiplexed parallel reactive power compensation ground fault full compensation system of the present invention. In this embodiment, the target power system is a 10kV neutral point ungrounded system. Phase power supply converter 1 adopts a 10kV/0.4kV three-phase transformer with a capacity of 2.2MVA and a connection group of Yyn6, one side of which is connected to the system bus, the other side is connected to a multiplexing compensation device, and the neutral point of this side is grounded . Multiplexing compensation device 2 adopts 0.4kV/2MVA TCR reactive power compensation device, adopts star connection mode, and the neutral point is grounded. The ground fault compensation switch 3 adopts three single-phase circuit breakers. One end of the three single-phase circuit breakers is connected to the phase power supply converter and the multiplexing compensation device, and the other end is short-circuited and connected to the injection transformer 4 . The injection transformer 4 adopts a single-phase 0.4kV/5.7kV, ±20% adjustable voltage regulating transformer with a capacity of 0.2MVA. One side is connected to the ground fault compensation switch 3 and the ground, and the other side is connected to the system neutral point and the ground. The multiplexing controller 5 controls the multiplexing compensation device 2 to dynamically compensate the reactive power and harmonics of the power grid system during normal operation of the system to meet the requirements of the reactive power and harmonics of the power grid system; when a single-phase ground fault occurs in the system, judge For the ground phase, close the ground fault corresponding switch of the ground fault compensation switch 3, adjust the inductance of the ground fault phase input of the multiplexing compensation device 2 and/or the transformation ratio of the injection transformer 4 to realize full ground fault compensation.

As shown in Fig. 5, it is the second specific implementation mode of a multiplexed parallel reactive power compensation ground fault full compensation system of the present invention. In this embodiment, the target power system is a 10kV neutral point ungrounded system. Phase power supply converter 1 adopts a combination of 10kV/10kV, capacity 2.2MVA, connection group Dyn7 three-phase transformer and 10kV/10kV, capacity 2.2MVA, connection group Dyn11 three-phase transformer, one side of which is connected to the system busbar, the other side is connected to the multiplexing compensation device, and the neutral point of the Dyn11 transformer is grounded. Multiplexing compensation device 2 adopts 10kV/2MVA TSC reactive power compensation device, adopts star connection mode, and the neutral point is grounded. The ground fault compensation switch 3 adopts three single-phase circuit breakers. One end of the three single-phase circuit breakers is connected to the phase power supply converter and the multiplexing compensation device, and the other end is short-circuited and connected to the injection transformer 4 . The injection transformer 4 is a 5.7kV/5.7kV, adjustable ±20%, single-phase voltage regulating transformer with a capacity of 0.2MVA. One side is connected to the ground fault compensation switch 3 and the ground, and the other side is connected to the system neutral point and the ground. The multiplexing controller 5 controls the multiplexing compensation device 2 to dynamically compensate the reactive power and harmonics of the power grid system during normal operation of the system to meet the requirements of the reactive power and harmonics of the power grid system; when a single-phase ground fault occurs in the system, judge For the ground phase, close the ground fault corresponding switch of the ground fault compensation switch 3, and adjust the capacitive reactance of the ground fault phase input of the multiplexing compensation device 2 and/or the transformation ratio of the injection transformer 4 to realize full ground fault compensation.

As shown in Fig. 6, it is the third specific implementation mode of a multiplexed parallel reactive power compensation ground fault full compensation system of the present invention. In this embodiment, the target power system is a 10kV neutral point ungrounded system. Phase power supply converter 1 adopts a 10kV/10kV three-phase transformer with a capacity of 2.2MVA and a connection group of Yyn6, one side of which is connected to the system bus, the other side is connected to a multiplexing compensation device, and the neutral point of this side is grounded. Multiplexing compensation device 2 adopts 10kV/2MVA SVG reactive power compensation device, the compensation device adopts chain structure, the compensation module adopts star connection mode, and the neutral point is grounded. The ground fault compensation switch 3 adopts three single-phase circuit breakers, one end of the three single-phase circuit breakers is connected to each phase of the phase power supply converter 1 and the multiplexing compensation device 2, and the other end is short-circuited and connected to the injection transformer, 4. The injection transformer 4 is a 5.7kV/5.7kV, adjustable ±20%, single-phase voltage regulating transformer with a capacity of 0.2MVA. One side is connected to the ground fault compensation switch and the ground, and the other side is connected to the system neutral point and the ground. The multiplexing controller 5 controls the multiplexing compensation device 2 to dynamically compensate the reactive power and harmonics of the power grid system during normal operation of the system to meet the requirements of the reactive power and harmonics of the power grid system; when a single-phase ground fault occurs in the system, judge For the ground phase, close the ground fault corresponding switch of the ground fault compensation switch 3, adjust the output voltage of the ground fault phase of the multiplexing compensation device 2 and/or inject the transformation ratio of the transformer 4 to realize full ground fault compensation.

To sum up, the ground fault full compensation system and method provided by the application for multiplexing parallel reactive power compensation improves the utilization rate of the ground fault full compensation device, realizes the full life cycle operation of the device, and increases the value of power system assets; intensive Compared with the current two sets of reactive power compensation and single-phase grounding full compensation systems, the ground fault full compensation system with multiplexed parallel reactive power compensation has a greatly reduced volume, is convenient to deploy and implement, and has a lower overall cost.

Since the above implementation methods are described in conjunction with reference to other methods, different embodiments have the same parts, and the same and similar parts between the various embodiments in this specification can be referred to each other. No further elaboration here.

Other embodiments of the present application will be readily apparent to those skilled in the art from consideration of the specification and practice of the inventive disclosure herein. This application is intended to cover any modification, use or adaptation of the present invention, these modifications, uses or adaptations follow the general principles of the application and include common knowledge or conventional technical means in the technical field not disclosed in the application . The specification and examples are to be considered exemplary only, with the true scope and spirit of the application indicated by the contents of the appended claims.

The embodiments of the present application described above are not intended to limit the scope of protection of the present application.

Claims (8)

1. A ground fault full compensation system for multiplexing parallel reactive compensation, the system comprising a phase power supply converter (1), a multiplexing compensation device (2), a ground fault compensation switch (3), an injection transformer (4) and a multiplexing controller (5), wherein:

the phase power supply converter (1) is used for converting a system line voltage into a phase voltage opposite to a system phase power supply to serve as a compensation power supply of single-phase grounding full compensation;

the multiplexing compensation device (2) is a reactive compensation device and comprises any one of a TCR mode, a TCT mode, a TSC mode, an SVG mode and a grouping switched capacitor bank mode;

one side of the phase power supply converter (1) is connected with a power system bus, and the other side of the phase power supply converter is connected with the multiplexing compensation device (2);

the multiplexing compensation device (2) is grounded;

one end of the multiplexing compensation device (2) is connected with the phase power supply converter (1), and the other end of the multiplexing compensation device is connected with the ground fault compensation switch (3);

one end of the ground fault compensation switch (3) is connected with the multiplexing compensation device (2), and the other end of the ground fault compensation switch is connected with the injection transformer (4);

the other end of the injection transformer (4) is connected with a neutral point of a power system and the ground respectively;

the multiplexing controller (5) is connected with the multiplexing compensation device (2), the ground fault compensation switch (3) and the injection transformer (4) and is used for judging the running state of the system;

the multiplexing controller (5) comprises:

the system signal acquisition module (51) is used for acquiring bus voltage, bus load current, line current, multiplexing compensation device voltage and multiplexing compensation device current signals of the power system;

the system state judging and switching module (52) is used for judging whether the power system is in a normal operation state or a single-phase earth fault state according to the signal acquired by the system signal acquisition module (51) and controlling the earth fault compensation switch (3);

the reactive compensation control module (53) is used for controlling the multiplexing compensation device (2) to output reactive power required by the power system according to the signal acquired by the system signal acquisition module (51);

and the ground fault full compensation control module (54) is used for controlling the transformation ratio of the injection transformer (4) to adjust the compensation voltage and the compensation current during single-phase grounding according to the signal acquired by the system signal acquisition module (51).

2. The system for ground fault full compensation of multiplexed parallel reactive compensation according to claim 1, wherein the multiplexing controller (5) further comprises a protection module (55) for isolating system faults in case of short circuit, overload faults.

3. The system for ground fault full compensation with multiplexing parallel reactive compensation according to claim 1, characterized in that the phase power supply converter (1) is a transformer or a combination of transformers;

the phase power supply converter (1) is used for providing a reactive compensation channel isolated from a power system.

4. The system for ground fault full compensation of multiplexing parallel reactive compensation according to claim 1, characterized in that the multiplexing compensation device (2) adopts a star connection mode.

5. The system for ground fault full compensation of multiplexed parallel reactive compensation according to claim 1, characterized in that the ground fault compensation switch (3) is a combination of three single phase switches.

6. The system for ground fault full compensation of multiplexed parallel reactive compensation according to claim 1, characterized in that the injection transformer (4) is a single-phase transformer ratio adjustable transformer.

7. The system for ground fault full compensation with multiplexed parallel reactive compensation according to claim 1, wherein the power system neutral point is a system neutral point led out by a grounding transformer, a system neutral point led out by a main transformer of a power system, or a system neutral point led out by the phase power supply converter (1).

8. A method for multiplexing ground fault full compensation of parallel reactive compensation, the method comprising the steps of:

judging the running state of the system;

when the single-phase earth fault does not occur in the power system, the earth fault compensation switch is switched off, and the multiplexing compensation device carries out reactive power compensation on the power system;

when the power system has single-phase earth fault, judging the earth phase, closing the corresponding switch of the earth fault compensation switch, and adjusting the multiplexing compensation device and the injection transformer to perform single-phase earth fault full compensation;

and judging whether the single-phase earth fault disappears, if so, disconnecting the earth fault compensation switch, and performing reactive power compensation on the power system by the multiplexing compensation device, and if not, continuing to perform single-phase earth fault full compensation.

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