CN205811531U - Fault protection system for power distribution system - Google Patents

Abstract

The utility model discloses a fault protection system for a power distribution system, in which a grounding transformer protection device, a neutral point protection device, a station transformer protection device, a line protection device, a capacitor protection device, a low backup protection device, a high backup protection device and a segment protection device are respectively connected to the A network and the B network of the station control layer in the power distribution system and the synchronous timing network, and each protection device exchanges its own operating state and the opening and closing state of the circuit breaker connected to it through the A network and the B network. The utility model can make the grounding transformer protection device know the location of the single-phase grounding fault in time through network information interaction. When a single-phase grounding fault occurs, the grounding transformer protection device no longer needs to wait for the action time of other protection devices, but can directly act according to its own delay, thereby reducing the protection action time, having high sensitivity, and realizing the rapid removal of the single-phase grounding fault as much as possible.

Description

A Fault Protection System for Power Distribution System

technical field

The utility model relates to the technical field of power distribution fault processing, in particular to a fault protection system for power distribution systems.

Background technique

With the continuous expansion of the distribution network scale, how to ensure the timely detection and isolation of single-phase ground faults, and how to ensure the reliability of the power supply of the distribution network while ensuring the safety of people and equipment is a major problem. With the development of domestic distribution network construction and the extensive use of special cable lines in the distribution network, the capacitive current of the distribution system is also increasing. When a single-phase ground fault occurs, due to the large capacitive current, the arc cannot Self-extinguishing, especially when high-impedance grounding occurs, there is no way to quickly and accurately select the line to trip, resulting in the expansion of single-phase grounding faults, which seriously threatens the safety of people and equipment.

At present, the preferred neutral point grounding method of the power system is to use the neutral point through the arc suppression coil to connect a small resistor in parallel. This neutral point grounding method makes full use of the characteristics of the two grounding methods, and the instantaneous Faults and permanent single-phase-to-earth faults can be treated separately.

If an instantaneous single-phase ground fault occurs, the arc suppressing coil will play a role, the single-phase ground fault will be automatically eliminated, and the power distribution system will return to normal operation, without power failure for users. In the event of a permanent single-phase ground fault, the arc is first extinguished by the arc suppression coil, and after a period of operation, the neutral point small resistor is put into operation. The zero-sequence current at the single-phase ground fault point increases, and the protection device on the line Or the action of the ground transformer protection device will isolate the single-phase ground fault.

However, in the existing method, when a single-phase ground fault occurs in the line interval, the protection device on the line will control the corresponding circuit breaker to disconnect after the T1 time. If the single-phase ground fault still exists, after the T2 time, Then the protective device of the grounding transformer trips the upper-level circuit breaker; and when a single-phase ground fault occurs in the busbar or the grounding transformer bay, the protective device on the line will not operate, but the protective device of the grounding transformer still needs to wait for T1+T2 time. will move. It can be seen that when a single-phase ground fault occurs in a non-line interval, the ground transformer protection device also operates after a long delay. The protection action time is long and the sensitivity is poor. The system has a large adverse effect.

Therefore, how to provide a fast-acting and highly sensitive fault protection system for power distribution systems is a problem that those skilled in the art need to solve.

Utility model content

The purpose of this utility model is to provide a fault protection system for power distribution systems, which reduces the protection action time and has high sensitivity, and realizes the rapid removal of single-phase ground faults as much as possible, so that single-phase ground faults are harmful to personal, The adverse effects brought by equipment and power distribution system are minimized.

In order to solve the above technical problems, the utility model provides a fault protection system for power distribution system, including:

The grounding transformer protection device connected with the control terminal of the grounding transformer circuit breaker; the high backup protection device connected with the main transformer high voltage side circuit breaker; the low backup protection device connected with the main transformer low voltage side circuit breaker; connected with the section interval circuit breaker Sectional protection devices; several substation protection devices respectively connected to the control terminals of the corresponding substation circuit breakers; several line protection devices respectively connected to the control terminals of the corresponding line circuit breakers; Several capacitor protection devices connected to the control terminal of the capacitor circuit breaker;

connected to the control terminal of the input circuit breaker of the neutral point small resistance, and used to control the input circuit breaker to close when it is judged that the zero-sequence voltage on the bus connected to it reaches the preset voltage threshold and lasts for the first preset time Neutral point protection device; wherein, the small resistor is connected in parallel with the arc suppression coil;

The grounding substation protection device, the neutral point protection device, several substation protection devices, several line protection devices, several capacitor protection devices, the low backup protection device, the The high backup protection device and the segmented protection device are respectively connected to the A network and the B network of the station control layer in the power distribution system and the synchronous time synchronization network, and each protection device passes through the A network and the B network Interact with each other about their operating status and the on/off status of their connected circuit breakers.

Preferably, the grounding substation protection device, the neutral point protection device, several substation protection devices, several line protection devices, several capacitor protection devices, and the low backup protection device , the high backup protection device and the section protection device are also respectively connected to the GOOSE+SV network of the process layer in the power distribution system.

Preferably, the grounding transformer protection devices are respectively connected to the control terminals of the main transformer low-voltage side circuit breaker, the main transformer high-voltage side circuit breaker, and the section interval circuit breaker; the grounding transformer protection devices directly control Opening and closing states of the main transformer low-voltage side circuit breaker, the main transformer high-voltage side circuit breaker, and the section bay circuit breaker.

Preferably, the low backup protection device is connected to the control terminal of the main transformer low-voltage side circuit breaker;

The high backup protection device is connected to the control terminal of the high voltage side circuit breaker of the main transformer;

The section protection device is connected to the control terminal of the section breaker;

The grounding change protection device sends corresponding control signals to the low backup protection device or the high backup protection device or the section protection device through the network connected to it, and the low backup protection device or the high backup protection device The backup protection device or the section protection device controls the opening and closing state of its corresponding circuit breaker according to the received control signal.

Preferably, the grounding transformer protection device, several of the station transformer protection devices, several of the line protection devices, and several of the capacitor protection devices are all connected to a zero-sequence current transformer;

The substation protection device, the line protection device and the capacitor protection device respectively include:

A first zero-sequence protection module used to trigger the zero-sequence current mutation calculation module to start when the zero-sequence voltage on the bus connected to it reaches the preset voltage threshold;

It is used to calculate the change value of the zero-sequence current on the zero-sequence current transformer connected to it before and after the neutral point small resistance is switched on and the said Whether the ratio of the initial value of the zero-sequence current before the neutral point small resistance is input exceeds the corresponding preset ratio range, and if so, trigger the zero-sequence current mutation calculation module of the first zero-sequence current protection module;

The first zero-sequence current protection module is used to send a message that the zero-sequence current mutation protection has been activated to the network connected to it, and control the disconnection of the circuit breaker connected to it;

The ground change protection device specifically includes the first zero-sequence protection module, the zero-sequence current sudden change calculation module, and a device for selecting the operating state of each protection device and the opening and closing state of each circuit breaker received from the network. The corresponding preset control strategy is used to control the second zero-sequence current protection module that the corresponding circuit breaker is disconnected;

The neutral point protection device specifically includes a second zero-sequence protection module configured to control the input circuit breaker to close when the zero-sequence voltage on the bus connected to it reaches the preset voltage threshold.

Preferably, when the grounding transformer protection device, several of the station transformer protection devices, several of the line protection devices and several of the capacitor protection devices are connected to a three-phase current transformer respectively, the The grounding substation protection device, the station substation protection device, the line protection device and the capacitor protection device also include:

It is used to compare whether the self-produced zero-sequence current on the three-phase current transformer connected to itself is greater than the zero-sequence current transformer connected to itself when receiving a message that the circuit breaker is not switched on through the network The measured zero-sequence current on the transformer is greater than the first preset current value, if so, sending a message indicating that the three-phase current transformer is faulty to the first judging module of the network connected to it;

It is used to compare whether the self-produced zero-sequence current on the three-phase current transformer connected to itself is greater than the zero-sequence current transformer connected to itself when receiving the message that the circuit breaker is switched on through the network and the self-produced zero-sequence current is greater than the second preset current value and the measured zero-sequence current is less than the third preset current value, if so, send a fault report of the zero-sequence current transformer The second judging module uses the measured zero-sequence current on the three-phase current transformer as its corresponding zero-sequence current sudden change calculation module to calculate the zero-sequence current.

The utility model provides a fault protection system for a power distribution system, in which a grounding substation protection device, a neutral point protection device, a station substation protection device, a line protection device, a capacitor protection device, a low backup protection device, The high backup protection device and the section protection device are respectively connected to the A network and B network of the station control layer and the synchronous time synchronization network in the power distribution system, and each protection device exchanges its own operating status and its own connection through the A network and the B network The open and closed state of the circuit breaker. It can be seen that in the utility model, through network information interaction, the grounding substation protection device can know the location of the single-phase ground fault in time. When the single-phase ground fault occurs, the substation protection device, line protection device and capacitor protection device When none of them act, it indicates that a single-phase ground fault has occurred in the busbar or the ground transformer bay. At this time, the ground transformer protection device no longer needs to wait for the action time of other protection devices (that is, T1), but directly operates according to its own delay That is, the protection action time is reduced, the sensitivity is high, and the single-phase ground fault is quickly removed as much as possible, so that the adverse effects of the single-phase ground fault on the person, equipment and power distribution system are minimized.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings that need to be used in the prior art and the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only the present invention. For some embodiments of the present invention, those of ordinary skill in the art can also obtain other drawings based on these drawings on the premise of not paying creative efforts.

Fig. 1 is a structural schematic diagram of the equipment wiring part of a fault protection system for a power distribution system provided by the utility model;

Fig. 2 is a schematic structural diagram of a network connection part of a fault protection system for a power distribution system provided by the utility model.

detailed description

The core of the utility model is to provide a fault protection system for power distribution systems, which reduces the protection action time and has high sensitivity, and realizes the rapid removal of single-phase ground faults as much as possible, so that single-phase ground faults are harmful to personal, The adverse effects brought by equipment and power distribution system are minimized.

In order to make the purpose, technical solutions and advantages of the embodiments of the utility model more clear, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described The embodiments are some embodiments of the present utility model, but not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Embodiment one

The utility model provides a fault protection system for a power distribution system, as shown in Figure 1, which is a structural schematic diagram of the equipment wiring part of a fault protection system for a power distribution system provided by the utility model; The system includes:

The grounding transformer protection device connected with the control terminal of the grounding transformer circuit breaker; the high backup protection device connected with the main transformer high-voltage side circuit breaker; the low backup protection device connected with the main transformer low-voltage side circuit breaker; and the section interval circuit breaker FDL connected section protection devices; several substation protection devices respectively connected to the control ends of the corresponding substation circuit breakers; several line protection devices respectively connected to the control ends of the corresponding line circuit breakers; respectively connected to the corresponding Several capacitor protection devices connected to the control terminal of the capacitor circuit breaker;

Connected to the control terminal of the input circuit breaker DL with a small resistance at the neutral point, it is used to control the input circuit breaker DL to close when it is judged that the zero-sequence voltage on the bus connected to it reaches the preset voltage threshold and lasts for the first preset time Neutral point protection device; wherein, a small resistor is connected in parallel with the arc suppression coil;

Grounding substation protection device, neutral point protection device, several substation protection devices, several line protection devices, several capacitor protection devices, low backup protection device, high backup protection device and section protection device are respectively connected with power distribution The A network and B network of the station control layer in the system are connected with the synchronous time synchronization network, and each protection device interacts with each other through the A network and the B network to communicate their respective operating status and the opening and closing status of the circuit breakers connected to each other.

Of course, the number of line protection devices, station substation protection devices and capacitor protection devices depends on specific conditions, which is not limited by the present invention.

The present invention does not limit the specific values of the preset voltage threshold and the first preset time.

The utility model provides a fault protection system for a power distribution system, in which a grounding substation protection device, a neutral point protection device, a station substation protection device, a line protection device, a capacitor protection device, a low backup protection device, The high backup protection device and the section protection device are respectively connected to the A network and B network of the station control layer and the synchronous time synchronization network in the power distribution system, and each protection device exchanges its own operating status and its own connection through the A network and the B network The open and closed state of the circuit breaker. It can be seen that in the utility model, through network information interaction, the grounding substation protection device can know the location of the single-phase ground fault in time. When the single-phase ground fault occurs, the substation protection device, line protection device and capacitor protection device When none of them act, it indicates that a single-phase ground fault has occurred in the busbar or the ground transformer bay. At this time, the ground transformer protection device no longer needs to wait for the action time of other protection devices (that is, T1), but directly operates according to its own delay That is, the protection action time is reduced, the sensitivity is high, and the single-phase ground fault is quickly removed as much as possible, so that the adverse effects of the single-phase ground fault on the person, equipment and power distribution system are minimized.

Embodiment two

On the basis of Embodiment 1, as a preference, grounding substation protection devices, neutral point protection devices, several substation protection devices, several line protection devices, several capacitor protection devices, low backup protection devices, high backup protection devices The protection device and the section protection device are respectively connected with the GOOSE+SV network of the process layer in the power distribution system. Referring to Fig. 2, Fig. 2 is a structural schematic diagram of a network connection part of a fault protection system for a power distribution system provided by the utility model.

It can be understood that, in order to ensure the consistency of the data collection time of each device and the identifiable time sequence, all the above devices need to be connected to a synchronous time synchronization system. The above devices fully support the IEC 61850 standard, and their network interfaces all have SV digital sampling and GOOSE message exchange functions based on the IEC 61850 standard, and can receive real-time digital signals from other devices across devices through the IEC 61850-9-2 protocol. The main purpose of using the GOOSE message mechanism is to exchange information quickly and accurately. The main purpose of using three networks to exchange information at the same time is to improve reliability, that is, when one of the networks is abnormal or disconnected, information exchange should be possible through other networks. Of course, the present invention does not limit the network interface types and adopted protocols of each device.

Among them, the types of information that each device needs to collect and send through the network are as follows:

#1 main transformer low-voltage backup protection device needs to collect the operation information of this interval: #1 transformer low-voltage side circuit breaker 1B-DL position (closed position, sub-position); #1 main transformer low-voltage side A-phase current, B-phase current, Phase C current; zero-sequence voltage of the bus in this section.

The protection device on the low-voltage side of #2 main transformer needs to collect the operating information of this interval: #2 transformer low-voltage side circuit breaker 2B-DL position (closed position, divided position); #2 main transformer low-voltage side A-phase current, B-phase current, Phase C current; zero-sequence voltage of the bus in this section.

The line protection device needs to collect the operation information of this interval: the position of the line circuit breaker in this interval (closed position, divided position); the zero-sequence current of this line interval; the zero-sequence voltage of the bus in this section.

The protection device of #1 grounding substation needs to collect the operation information of this bay: the position of the grounding substation circuit breaker of this bay (closed position, partial position); the neutral point zero-sequence current of this grounding substation bay; the bus zero-sequence voltage of this section.

#2 The grounding substation protection device needs to collect the operation information of this bay: the position of the grounding substation circuit breaker of this bay (closed position, partial position); the neutral point zero-sequence current of this grounding substation bay; the bus zero-sequence voltage of this section.

#1 station substation protection device needs to collect the operation information of this bay: the station substation circuit breaker position (closing position, sub-position) of this bay; the station substation transformer bay zero-sequence current; the bus zero-sequence voltage of this section.

#2 Station substation protection device needs to collect the operation information of this interval: the station substation circuit breaker position (closing position, separation position); the substation substation zero sequence current; the bus zero sequence voltage of this section.

The #1 capacitor protection device needs to collect the operation information of this interval: the position of the capacitor circuit breaker in this interval (closed position, divided position); the zero-sequence current of this capacitor interval; the zero-sequence voltage of the bus in this section.

#2 The capacitor protection device needs to collect the operation information of this interval: the position of the capacitor circuit breaker in this interval (closed position, divided position); the zero-sequence current of this capacitor interval; the zero-sequence voltage of the bus in this section.

The segmented protection device needs to collect the operation information of this interval: the FDL position of the segmented interval circuit breaker (closed position, divided position); the A-phase current, B-phase current, and C-phase current of this segmented interval.

#1 neutral point protection device needs to collect the operation information of this interval: #1 grounding transformer neutral point arc suppressing coil parallel connection small resistance system zero voltage, neutral point zero sequence current, input circuit breaker DL position (closed position, quantile).

The #2 neutral point protection device needs to collect the operating information of this interval: #2 grounding transformer neutral point arc suppression coil parallel connection small resistance system zero voltage, neutral point zero sequence current, input circuit breaker DL position (closing, opening bits).

In a specific embodiment, the grounding transformer protection devices are respectively connected to the control terminals of the main transformer low-voltage side circuit breaker, the main transformer high-voltage side circuit breaker, and the segmental interval circuit breaker FDL; the grounding transformer protection devices directly control the main transformer low-voltage side Opening and closing status of the circuit breaker, main transformer high voltage side circuit breaker and section bay circuit breaker FDL.

In another specific embodiment, the low backup protection device is connected to the control terminal of the main transformer low-voltage side circuit breaker;

The high backup protection device is connected to the control terminal of the high voltage side circuit breaker of the main transformer;

The section protection device is connected to the control terminal of the section breaker FDL;

The grounding change protection device sends corresponding control signals to the low backup protection device or high backup protection device or section protection device through the network connected to it, and the low backup protection device or high backup protection device or section protection device according to the received The control signal is used to control the opening and closing state of its corresponding circuit breaker.

It can be understood that both of the above two connection control methods can realize grounding protection, and the utility model does not limit which method is used specifically.

Preferably, the grounding transformer protection device, several station transformer protection devices, several line protection devices and several capacitor protection devices are connected to a zero-sequence current transformer 11 respectively;

The substation protection device, line protection device and capacitor protection device respectively include:

The first zero-sequence protection module used to trigger the zero-sequence current mutation calculation module to start when the zero-sequence voltage on the bus connected to it reaches a preset voltage threshold;

It is used to calculate the change value of the zero-sequence current on the zero-sequence current transformer 11 connected to it before and after the input of the small neutral point resistance and the change value of the neutral point small resistance input Whether the ratio of the initial value of the previous zero-sequence current exceeds the corresponding preset ratio range, and if so, trigger the zero-sequence current mutation calculation module of the first zero-sequence current protection module;

The first zero-sequence current protection module used to send a message that the zero-sequence current mutation protection has been activated to the network connected to it, and control the disconnection of the circuit breaker connected to it;

The grounding change protection device specifically includes a first zero-sequence protection module, a zero-sequence current mutation calculation module, and a corresponding preset control strategy for selecting the corresponding preset control strategy according to the operating status of each protection device received from the network and the opening and closing status of each circuit breaker To control the second zero-sequence current protection module that the corresponding circuit breaker is disconnected;

The neutral point protection device specifically includes a second zero-sequence protection module for controlling closing of the input circuit breaker DL when the zero-sequence voltage on the bus connected to it reaches a preset voltage threshold.

It is understandable that the zero-sequence current at the location of the single-phase ground fault will increase after the connection of a small resistor at the neutral point, so the purpose of judging the magnitude of the zero-sequence current is to determine the location of the single-phase ground fault. In the existing technology, it is impossible to judge whether the small resistance of the neutral point is connected to the circuit in time, so when judging the zero-sequence current, only a large preset value can be set in advance. When the zero-sequence current exceeds the preset value, it indicates that A single-phase grounding fault occurs in the branch connected to the zero-sequence current transformer 11; however, when a high-impedance grounding occurs, the preset value is easily not reached, and the zero-sequence current protection cannot be activated in time, so it is easy to cause a phase-to-phase short circuit.

However, the utility model adopts the calculation of sudden change to judge, that is, to judge whether the ratio of the change value of the zero-sequence current before and after the connection of the small neutral point resistance to the initial value of the zero-sequence current before the connection of the small neutral point resistance exceeds the preset value Ratio range, so that even if the value of the zero-sequence current increase may not be very large, once the increase ratio of the zero-sequence current exceeds the preset ratio range, it means that the branch has a single-phase ground fault. It can be seen that the calculation of the sudden change solves the problem. The problem that the preset value cannot be reached when the high resistance is grounded greatly improves the sensitivity of single-phase ground fault detection, as well as the safety and reliability of the single-phase ground fault protection system.

Preferably, when the grounding substation protection device, several substation protection devices, several line protection devices and several capacitor protection devices are respectively connected to a three-phase current transformer, the grounding substation protection device, station substation protection The device, line protection device and capacitor protection device also include:

It is used to compare whether the self-produced zero-sequence current on the three-phase current transformer connected to itself is greater than the actual measurement on the zero-sequence current transformer 11 connected to itself when receiving a message that the circuit breaker DL is not switched on through the network The zero-sequence current is greater than the first preset current value, if so, sending a message indicating that the three-phase current transformer is faulty to the first judging module of the network connected to it;

It is used to compare whether the self-produced zero-sequence current on the three-phase current transformer connected to itself is greater than the measured zero-sequence current on the zero-sequence current transformer 11 connected to itself when receiving the message of switching on the circuit breaker DL through the network. sequence current and the self-produced zero-sequence current is greater than the second preset current value and the measured zero-sequence current is less than the third preset current value, if so, send a fault message of zero-sequence current transformer 11 to the network, and send The measured zero-sequence current on the transformer is used as the second judging module of the zero-sequence current during calculation by its corresponding zero-sequence current sudden change calculation module.

It can be understood that, by including the above-mentioned modules, the grounding substation protection device, station substation protection device, line protection device and capacitor protection device can check whether the three-phase current transformer and the zero-sequence current transformer 11 connected to itself are faulty or not. Check to avoid the failure of the zero-sequence current transformer 11 and affect the detection of the ground fault.

The present invention does not limit the specific values of the above preset ratio range, the first preset current value, the second preset current value and the third preset current value.

In order to facilitate the understanding of the solution of the utility model, the following is a brief introduction of the protection action of the fault protection system for power distribution system provided by the utility model when a single-phase grounding fault occurs in several specific working states:

State 1: The circuit breaker 1B-DL on the low-voltage side of #1 transformer is in position, the section breaker FDL is in position, and the circuit breaker 2DL in #1 grounding transformer is in position, that is, the #1 main transformer is running with the 10kV bus of section I and Only the #1 ground changer is in the run position.

When the zero-sequence current transformer 11 connected to the line protection device (or substation transformer protection device or capacitor protection device) has a permanent single-phase ground fault at any position away from the busbar side (Note: if a transient single-phase ground fault occurs , then the arc suppression coil will play a role, the single-phase ground fault will be eliminated automatically, and the power distribution system will return to normal operation), the action process is as follows:

At this time, the zero-sequence voltage of the power distribution system rises. When the preset voltage threshold is reached, the zero-sequence current mutation calculation function of the line protection device (or substation transformer protection device or capacitor protection device) enters the start-up preparation state. The protection device (or substation transformer protection device or capacitor protection device) receives the neutral point small resistance input from the #1 neutral point protection device through the aforementioned A network, B network and GOOSE+SV network (that is, the input of the circuit breaker DL After the GOOSE message, the zero-sequence current mutation calculation is started. When the ratio of the zero-sequence current change value to the initial value reaches the preset ratio range, the A network, B network and GOOSE+SV network are sent to the local The #1 grounding transformer protection device of the busbar sends a message that the zero-sequence current mutation protection of this interval has been started, and then trips the circuit breaker controlled by this interval after the first preset delay time T1, that is, trips the line circuit breaker (or station Use transformer circuit breaker or capacitor circuit breaker), and send the zero-sequence current mutation protection of this interval to the #1 grounding transformer protection device of this bus through A network, B network and GOOSE+SV network at the same time. GOOSE message (hereinafter all use "fault" to represent "single-phase ground fault").

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the #1 neutral point protection device will input the small resistance of the neutral point after the second preset delay time T2 (that is, put the circuit breaker DL into position), At the same time, send the information of changing the position of the input circuit breaker DL from the position to the position through the A network, the B network and the GOOSE+SV network in the form of GOOSE messages to #1 grounding change protection device and other protection devices (including the aforementioned line protection device) , Capacitor protection device, station transformer protection device, etc.).

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the zero-sequence current mutation calculation function of the #1 grounding substation protection device enters the start-up preparation state. After receiving the GOOSE message from the #1 neutral point protection device for switching on the small resistance of the neutral point (that is, switching on the circuit breaker DL to close), the calculation of the zero-sequence current mutation is started. When the change value of the zero-sequence current is the same as the initial After the ratio of the values reaches the preset ratio range, if the #1 grounding substation protection device receives the bus through the aforementioned A network, B network and GOOSE+SV network within the third preset delay period T3 (for example, within 30 milliseconds) If the zero-sequence mutation protection has started GOOSE message sent by other intervals (line protection device or station transformer protection device or capacitor protection device), then the #1 grounding transformer protection device will continue to pass through the fourth preset delay time T4, Jump off the circuit breaker 1B-DL on the low-voltage side of the #1 transformer, and jump off the circuit breaker 1A-DL on the high-voltage side of the #1 transformer after the fifth preset delay time T5;

Specifically, if within the T4 delay time period (i.e. T3-T4 time period), the #1 grounding transformer protection device receives the GOOSE report that the zero-sequence current mutation protection has acted and sent a trip command sent at the same interval as the bus However, the zero-sequence current mutation protection of #1 grounding transformer did not return, that is, it was confirmed that the zero-sequence current transformer 11 of this interval had a permanent fault on the side far away from the busbar, and its protection was activated but the corresponding circuit breaker failed and tripped #1 transformer low-voltage side circuit breaker 1B-DL; if the #1 grounding transformer protection device receives the low voltage from the low backup protection device of #1 transformer through the aforementioned A network, B network and GOOSE+SV network within the time period T4-T5 The side circuit breaker 1B-DL is changed from closing position to position closing GOOSE message, and the zero-sequence current mutation protection of #1 grounding transformer returns, that is, it is confirmed that the low-voltage side of #1 transformer has acted and the fault has been removed, and #1 grounding transformer The protection can be returned, and at this time, the circuit breaker 1A-DL on the high-voltage side of the #1 transformer will not be tripped; The low-voltage side circuit breaker 1B-DL from the low backup protection device of the #1 transformer sent a GOOSE message from the closed position to the delimited position, and the zero-sequence current mutation protection of the #1 grounding change did not return, that is, it was confirmed that the #1 transformer was low-voltage The circuit breaker 1B-DL on the side fails and does not operate, and the circuit breaker 1A-DL on the high voltage side of the #1 transformer is required to remove the fault. At this time, the #1 grounding transformer protection device controls and trips the circuit breaker 1A-DL on the high voltage side of the #1 transformer.

If the #1 grounding substation protection device receives the GOOSE message that the zero-sequence current mutation protection has acted and sent a trip command sent at the same interval of the busbar within the T4 delay time period, and the zero-sequence current of #1 grounding substation The sudden change protection returns, that is, its protection action cuts off the fault, and the #1 grounding change protection can return.

Before the above-mentioned fault occurs, #1 grounding substation protection device, #1 neutral point protection device, line protection device of section I busbar, substation substation protection device and capacitor protection device are received through A network, B network and GOOSE+SV network respectively. To the GOOSE message information of the sub-section circuit breaker FDL being in position, and the GOOSE message information of #1 transformer low-voltage side circuit breaker 1B-DL being in position, each protection device has completed operation preparation.

State 2: #1 transformer low-voltage side circuit breaker 1B-DL is in position, section interval circuit breaker FDL is in position, #1 grounding transformer circuit breaker 2DL is in position, that is, #1 main transformer is running with section I 10kV busbar and Only the #1 ground changer is in the run position.

When the zero-sequence current transformer 11 connected to the line protection device (or substation transformer protection device or capacitor protection device) is connected to any position close to the busbar side and a permanent fault occurs on the busbar side of the transformer, the action process at this time is as follows:

The zero-sequence voltage of the power distribution system rises. When the preset voltage threshold is reached, the zero-sequence current mutation calculation function of the line protection device (or substation transformer protection device or capacitor protection device) enters the start-up preparation state. When the line protection device (or substation transformer protection device or capacitor protection device) through the aforementioned A network, B network and GOOSE+SV network, the neutral point small resistance input from #1 neutral point protection device is received (that is, the circuit breaker DL is closed) ) after the GOOSE message, start to calculate the zero-sequence current mutation amount, but in this case the zero-sequence current does not pass through the zero-sequence current transformer 11 connected to the line protection device (or station transformer protection device or capacitor protection device), Therefore, the zero-sequence current obtained by the line protection device (or substation transformer protection device or capacitor protection device) does not change, that is, the ratio of the change value of the zero-sequence current to the initial value cannot reach the preset ratio range, so the line protection device (or Substation transformer protection device or capacitor protection device) will not send the GOOSE message that the zero-sequence current mutation protection has started in this interval. When the zero-sequence voltage of the power distribution system decreases and is lower than the preset voltage threshold, the zero-sequence current mutation The compute function exits the active state.

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the #1 neutral point protection device will input the small resistance of the neutral point after the second preset delay time T2 (that is, put the circuit breaker DL into position), At the same time, send the information of changing the position of the input circuit breaker DL from the position to the position through the A network, the B network and the GOOSE+SV network in the form of GOOSE messages to #1 grounding change protection device and other protection devices (including the aforementioned line protection device) , Capacitor protection device, station transformer protection device, etc.).

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the zero-sequence current mutation calculation function of the #1 grounding substation protection device enters the start-up preparation state. After receiving the GOOSE message from the neutral point protection device for switching on the neutral point small resistance (that is, switching on the circuit breaker DL and closing the position), the calculation of zero-sequence current mutation is started. When the ratio of the change value of the zero-sequence current to the initial value reaches the preset ratio range, if the #1 grounding change protection device does not pass the aforementioned A network, B network and GOOSE+SV network receive the GOOSE message whose zero-sequence mutation protection has been started sent by other bays of the bus (line protection device or station transformer protection device or capacitor protection device), it is regarded as the zero-sequence message of other bays Permanent faults occur on the side of the current transformer 11 close to the busbar and on the busbar side of the transformer, and the #1 grounding transformer protection device needs to operate to clear the fault. Then the #1 grounding transformer protection device continues to trip the #1 transformer low-voltage side circuit breaker 1B-DL after the sixth preset delay time T6, and trips the #1 transformer high-voltage side circuit breaker after the seventh preset delay time T7 1A-DL.

Specifically, if the #1 grounding transformer protection device receives the low-voltage side circuit breaker 1B-DL from the low backup protection device of the #1 transformer through the aforementioned A network, B network and GOOSE+SV network within the time period T6-T7 The GOOSE message of bit-to-bit change, and the zero-sequence current mutation protection of #1 grounding transformer returns, that is, it is confirmed that the low-voltage side of #1 transformer has acted and the fault has been removed, and the protection of #1 grounding transformer can return, and no longer Jump off the #1 transformer high voltage side circuit breaker 1A-DL; if the #1 grounding transformer protection device does not receive the low backup protection device of the #1 transformer within the time period T6-T7 without the aforementioned A network, B network and GOOSE+SV network The GOOSE message that the low-voltage side circuit breaker 1B-DL is changed from close to delimited, and the zero-sequence current mutation protection of #1 grounding change does not return, that is, it is confirmed that the low-voltage side circuit breaker 1B-DL of #1 transformer is not faulty. Action requires #1 transformer high voltage side circuit breaker 1A-DL to cut off the fault. At this time, #1 grounding transformer protection device controls to trip #1 transformer high voltage side circuit breaker 1A-DL.

Before the above-mentioned fault occurs, #1 grounding substation protection device, #1 neutral point protection device, line protection device of section I busbar, substation substation protection device and capacitor protection device are received through A network, B network and GOOSE+SV network respectively. To the GOOSE message information of the sub-section circuit breaker FDL being in position, and the GOOSE message information of #1 transformer low-voltage side circuit breaker 1B-DL being in position, each protection device has completed operation preparation.

State three: #1 transformer low-voltage side circuit breaker 1B-DL is closing, #2 transformer low-voltage side circuit breaker 2B-DL is closing, section interval circuit breaker FDL is closing, #1 grounding transformer circuit breaker 2DL is closing Position, #2 grounding substation circuit breaker 6DL is at sub-position, that is, #1 main transformer runs with 2 sections of 10kV bus and only #1 grounding substation is in the operating position.

When the zero-sequence current transformer 11 connected to the line protection device (or substation transformer protection device or capacitor protection device) is permanently faulted at any position far away from the side of the bus bar in the bus area of section II, the action process is as follows:

At this time, the zero-sequence voltage of the power distribution system rises. When the preset voltage threshold is reached, the zero-sequence current mutation calculation function of the line protection device (or substation transformer protection device or capacitor protection device) enters the start-up preparation state. The protection device (or substation transformer protection device or capacitor protection device) receives the neutral point small resistance input from the #1 neutral point protection device through the aforementioned A network, B network and GOOSE+SV network (that is, the input of the circuit breaker DL After the GOOSE message, the zero-sequence current mutation calculation is started. When the ratio of the zero-sequence current change value to the initial value reaches the preset ratio range, the A network, B network and GOOSE+SV network are sent to the local The #1 grounding transformer protection device of the busbar sends a message that the zero-sequence current mutation protection of this interval has been started, and then trips the circuit breaker controlled by this interval after the first preset delay time T1, that is, trips the line circuit breaker (or station Use transformer circuit breaker or capacitor circuit breaker), and send the zero-sequence current mutation protection of this interval to the #1 grounding transformer protection device of this bus through A network, B network and GOOSE+SV network at the same time. GOOSE message.

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the #1 neutral point protection device will input the small resistance of the neutral point after the second preset delay time T2 (that is, put the circuit breaker DL into position), At the same time, the information of changing the position of the input circuit breaker DL from the position to the position is sent to the busbar grounding change protection device and other protection devices (including the aforementioned line protection device) through the A network, B network and GOOSE+SV network in the form of GOOSE messages. , capacitor protection device, station substation protection device, etc.);

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the zero-sequence current mutation calculation function of the #1 grounding substation protection device enters the start-up preparation state. After receiving the GOOSE message from the #1 neutral point protection device for switching on the neutral point small resistance (that is, turning on the circuit breaker DL and closing the position), the zero-sequence current mutation calculation starts. When the ratio of the change value of the zero-sequence current to the initial value reaches the preset ratio range, if the #1 grounding protection device passes through the aforementioned A network and B network within the third preset delay time period T3 (for example, within 30 milliseconds), And the GOOSE+SV network receives the GOOSE message that the zero-sequence mutation protection has been started from this bus or other intervals of the adjacent bus (line protection device or station transformer protection device or capacitor protection device), then the sixth preset The delay time T6 trips the segmental bay circuit breaker FDL, trips the #1 transformer low-voltage side circuit breaker 1B-DL after the seventh preset delay time T7, and trips the #1 transformer high-voltage side after the eighth preset delay time T8 Circuit breaker 1A-DL.

Specifically, during the T6 delay time period, if the #1 grounding change protection device receives the GOOSE message that the zero-sequence mutation protection of the busbar or the adjacent busbar at the same interval mentioned above has acted and sent a trip command, but #1 is grounded The changed zero-sequence current mutation protection does not return, that is, it is confirmed that the zero-sequence current transformer 11 at the same interval as the bus or the adjacent bus has a permanent fault at a position far away from the bus, and its protection operates but the corresponding circuit breaker fails. , jump off the segmental bay circuit breaker FDL; during the T6-T7 time period, the #1 grounding transformer protection device received the GOOSE message that the segmented bay circuit breaker FDL changed from close to partial, and the #1 grounding transformer zero-sequence Current mutation protection returns, that is, to confirm that the FDL trip of the sub-section circuit breaker is successful, and the #1 grounding change protection can return without tripping the #1 transformer low-voltage side circuit breaker 1B-DL; if #1 is within the T6-T7 time period The protection device of the grounding transformer did not receive the GOOSE message that the FDL of the segmental bay circuit breaker changed from close to partial position, and the zero-sequence current mutation protection of #1 grounding transformer did not return, that is, it was confirmed that the faulty FDL of the segmental bay circuit breaker did not trip successfully , #1 grounding transformer protection device trips #1 transformer low-voltage side circuit breaker 1B-DL; After the GOOSE message of the digit, and the zero-sequence current mutation protection of #1 grounding transformer returns, it is confirmed that #1 transformer low-voltage side circuit breaker 1B-DL has tripped successfully, and #1 grounding transformer protection can return, no need to trip again# 1 Transformer high-voltage side circuit breaker 1A-DL; if #1 grounding transformer protection device does not receive the GOOSE message from #1 transformer low-voltage side circuit breaker 1B-DL during the time period T7-T8, and #1 The zero-sequence current mutation protection of the grounding transformer does not return, that is, it is confirmed that the circuit breaker 1B-DL on the low-voltage side of the #1 transformer fails to trip successfully, and the protection device of the #1 grounding transformer needs to trip the circuit breaker 1A-DL on the high-voltage side of the #1 transformer.

During the T6 delay time period, if the #1 grounding transformer protection device receives the GOOSE message that the zero-sequence mutation protection of the busbar and the adjacent busbars have acted and sent a trip command, and the #1 grounding transformer is zero Sequence current mutation protection returns, that is, it is confirmed that the protection actions of other intervals have removed the fault, and #1 grounding change protection can return;

Before the aforementioned fault occurred, #1 grounding substation protection device, #1 neutral point protection device, line protection device for section I and section II buses, substation substation protection device and capacitor protection device passed through A network, B network and GOOSE+ respectively. The SV network receives the GOOSE message that the section breaker FDL is closing, the GOOSE message that #1 transformer low-voltage side circuit breaker 1B-DL is closing, and the #2 transformer low-voltage side circuit breaker 2B-DL is closing. The GOOSE message information of the 1st place, the GOOSE message information of the #2 grounding transformer circuit breaker 6DL in the 1st place, and each protection device has completed the operation preparation.

State 4: #1 transformer low-voltage side circuit breaker 1B-DL is closing, #2 transformer low-voltage side circuit breaker 2B-DL is closing, section interval circuit breaker FDL is closing, #1 grounding transformer circuit breaker 2DL is closing Position, #2 grounding substation circuit breaker 6DL is at sub-position, that is, #1 main transformer runs with 2 sections of 10kV bus and only #1 grounding substation is in the running position.

When the zero-sequence current transformer 11 connected to the line protection device (or substation transformer protection device or capacitor protection device) is connected to any position close to the busbar side and a permanent fault occurs on the busbar side of the transformer, the action process at this time is as follows:

The zero-sequence voltage of the power distribution system rises. When the preset voltage threshold is reached, the zero-sequence current mutation calculation function of the line protection device (or substation transformer protection device or capacitor protection device) enters the start-up preparation state. When the line protection device (or substation transformer protection device or capacitor protection device) through the aforementioned A network, B network and GOOSE+SV network, the neutral point small resistance input from #1 neutral point protection device is received (that is, the circuit breaker DL is closed) ) after the GOOSE message, start to calculate the zero-sequence current mutation amount, but in this case the zero-sequence current does not pass through the zero-sequence current transformer 11 connected to the line protection device (or station transformer protection device or capacitor protection device), Therefore, the zero-sequence current obtained by the line protection device (or substation transformer protection device or capacitor protection device) does not change, that is, the ratio of the change value of the zero-sequence current to the initial value cannot reach the preset ratio range, so the line protection device (or Substation transformer protection device or capacitor protection device) will not send the GOOSE message that the zero-sequence current mutation protection has started in this interval. When the zero-sequence voltage of the power distribution system decreases and is lower than the preset voltage threshold, the zero-sequence current mutation The compute function exits the active state.

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the #1 neutral point protection device will input the small resistance of the neutral point after the second preset delay time T2 (that is, put the circuit breaker DL into position), At the same time, the information of changing the position of the input circuit breaker DL from the position to the position is sent to the busbar grounding change protection device and other protection devices (including the aforementioned line protection device) through the A network, B network and GOOSE+SV network in the form of GOOSE messages. , Capacitor protection device, station transformer protection device, etc.).

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the zero-sequence current mutation calculation function of the #1 grounding substation protection device enters the start-up preparation state. After receiving the GOOSE message from the #1 neutral point protection device for switching on the neutral point small resistance (that is, turning on the circuit breaker DL and closing the position), the zero-sequence current mutation calculation starts. When the ratio of the change value of the zero-sequence current to the initial value reaches the preset ratio range, if the #1 grounding change protection device does not pass the aforementioned A network, B network and GOOSE+SV network receive the GOOSE message that the zero-sequence mutation protection has been started from this bus and other intervals of the adjacent bus (line protection device or station transformer protection device or capacitor protection device), it is considered to be other The zero-sequence current transformer 11 in the interval is permanently grounded at any position close to the busbar side and the busbar side of the transformer, etc., and the #1 grounding transformer protection device needs to operate to remove the fault, but at this time #1 grounding transformer protection device cannot distinguish Whether it is a fault in the section I bus area or a section II bus area fault, therefore, the #1 grounding transformer protection device trips the segmental bay circuit breaker FDL after the sixth preset delay time T6 (which can be equal to T3+30 milliseconds). After the preset delay time T7, the circuit breaker 1B-DL on the low-voltage side of the #1 transformer of section I bus is tripped, and the circuit breaker 1A-DL on the high-voltage side of the #1 transformer of section I bus is tripped after the eighth delay time T8.

Specifically, during the time period T6-T7, if the #1 grounding change protection device receives a GOOSE message from the segmental protection device through the network that the segmental interval circuit breaker FDL is from closed position to partial position, but #1 is grounded If the zero-sequence current sudden change protection does not return, it is considered that the fault occurred in the section I bus area, and after the seventh preset delay time T7, the #1 transformer low-voltage side circuit breaker 1B-DL will be tripped; if it is at T7-T8 During the time period, the #1 grounding transformer protection device received the GOOSE message from the low-voltage side circuit breaker 1B-DL of the #1 transformer through the aforementioned A network, B network and GOOSE+SV network. , and the zero-sequence current mutation protection of #1 grounding transformer returns, that is, it is confirmed that the low-voltage side of #1 transformer has acted and the fault has been removed, and the protection of #1 grounding transformer can return; if #1 grounding transformer The protection device did not receive the GOOSE message from the #1 transformer low-backup protection device of the low-voltage side circuit breaker 1B-DL through the aforementioned A network, B network and GOOSE+SV network, and #1 grounded The zero-sequence current mutation protection does not return, that is, it is confirmed that #1 transformer low-voltage side circuit breaker 1B-DL fails and does not act, and #1 transformer high-voltage side circuit breaker 1A-DL is required to remove the fault, then the eighth delay time T8 Trip #1 transformer high side circuit breaker 1A-DL.

If the #1 grounding transformer protection device does not receive the GOOSE message from the segmental protection device for the FDL of the segmental interval circuit breaker from close to partial position, and the zero-sequence current mutation protection of #1 grounding transformer does not return, then It is considered that the segmental bay circuit breaker FDL fails and refuses to operate, and after the seventh preset delay time T7, the #1 transformer low-voltage side circuit breaker 1B-DL is tripped;

If you receive a GOOSE message from the sub-section protection device for the sub-section breaker FDL from closed position to sub-position, and the zero-sequence current mutation protection of #1 grounding transformer returns, it is considered that the fault occurred in the bus area of section II , the fault has been isolated, and the power distribution system returns to normal power supply;

Before the aforementioned fault occurred, #1 grounding substation protection device, #1 neutral point protection device, line protection device for section I and section II buses, substation substation protection device and capacitor protection device passed through A network, B network and GOOSE+ respectively. The SV network receives the GOOSE message that the section breaker FDL is closing, the GOOSE message that #1 transformer low-voltage side circuit breaker 1B-DL is closing, and the #2 transformer low-voltage side circuit breaker 2B-DL is closing. The GOOSE message information of the 1st place, the GOOSE message information of the #2 grounding transformer circuit breaker 6DL in the 1st place, and each protection device has completed the operation preparation.

State five: #1 transformer low-voltage side circuit breaker 1B-DL is closing, #2 transformer low-voltage side circuit breaker 2B-DL is closing, segmental interval circuit breaker FDL is closing, #1 grounding transformer circuit breaker 2DL is separating position, #2 grounding transformer circuit breaker 6DL is in the closed position, that is, #1 main transformer is running with 2 sections of 10kV bus and only #2 grounding transformer is in the running position.

When the zero-sequence current transformer 11 connected to the line protection device (or substation transformer protection device or capacitor protection device) is permanently faulted at any position far away from the side of the bus bar in the bus area of section II, the action process is as follows:

At this time, the zero-sequence voltage of the power distribution system rises. When the preset voltage threshold is reached, the zero-sequence current mutation calculation function of the line protection device (or substation transformer protection device or capacitor protection device) enters the start-up preparation state. The protection device (or station transformer protection device or capacitor protection device) receives the neutral point small resistance input from the #2 neutral point protection device through the aforementioned A network, B network and GOOSE+SV network (that is, the input of the circuit breaker DL After the GOOSE message, the zero-sequence current mutation calculation is started. When the ratio of the zero-sequence current change value to the initial value reaches the preset ratio range, the A network, B network and GOOSE+SV network are sent to the local The #2 grounding transformer protection device of the busbar sends a message that the zero-sequence current mutation protection of this interval has started, and then trips the circuit breaker controlled by this interval after the first preset delay time T1, that is, trips the line circuit breaker (or station Using variable circuit breaker or capacitor circuit breaker), the single-phase ground fault is cut off, and the power distribution system returns to normal. When the aforementioned zero-sequence current mutation protection sends an order to trip the circuit breaker in this bay, the zero-sequence current mutation protection of this bay is sent to the #2 grounding transformer protection device of the bus through A network, B network and GOOSE+SV network at the same time. The GOOSE message of the action and the trip command has been sent;

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the #2 neutral point protection device will input the small resistance of the neutral point after the second preset delay time T2 (that is, put the circuit breaker DL into position), At the same time, the information of changing the position of the input circuit breaker DL from the position to the position is sent to the busbar grounding change protection device and other protection devices (including the aforementioned line protection device) through the A network, B network and GOOSE+SV network in the form of GOOSE messages. , Capacitor protection device, station transformer protection device, etc.).

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the zero-sequence current mutation calculation function of the #2 grounding substation protection device enters the start-up preparation state. After the #2 neutral point protection device sends the GOOSE message that the neutral point small resistance is switched on (that is, the circuit breaker DL is switched on), the calculation of the zero-sequence current mutation is started. When the ratio of the change value of the zero-sequence current to the initial value reaches the preset ratio range, if the #2 grounding change protection device passes through the aforementioned A network and B network within the third preset delay time period T3 (for example, within 30 milliseconds), And the GOOSE+SV network receives the GOOSE message that the zero-sequence mutation protection has been started from other intervals of the bus (line protection device or station transformer protection device or capacitor protection device), and jumps after the sixth preset delay time T6 Turn on the circuit breaker 1B-DL on the low voltage side of the #1 transformer, and jump off the circuit breaker 1A-DL on the high voltage side of the #1 transformer for the seventh preset delay time T7.

Specifically, during the T6 delay time period, if the #2 grounding substation protection device receives the GOOSE message that the zero-sequence mutation protection at the same interval of the busbar or the adjacent busbar has acted and sent a trip command, but #1 The zero-sequence current mutation protection of the grounding transformer does not return, that is, it is confirmed that the zero-sequence current transformer 11 in other intervals has a permanent fault at a position far away from the busbar, and its protection operates but the corresponding circuit breaker fails, then trip #1 Transformer low-voltage side circuit breaker 1B-DL; if #2 grounding change protection device receives the GOOSE message of #1 transformer low-voltage side circuit breaker 1B-DL changing from closed position to partial position within the time period T6-T7, and #2 is grounded The zero-sequence current mutation protection of the transformer returns, that is, confirm that the #1 transformer low-voltage side circuit breaker 1B-DL trips successfully, and the #2 grounding transformer protection can return, and there is no need to trip the #1 transformer high-voltage side circuit breaker 1A-DL; During the time period T6-T7, the protection device of #2 grounding transformer did not receive the GOOSE message from #1 transformer low-voltage side circuit breaker 1B-DL, and the zero-sequence current mutation protection of #2 grounding transformer did not return. That is, it is confirmed that #1 transformer low-voltage side circuit breaker 1B-DL fails to trip successfully, and #2 grounding transformer protection device needs to trip #1 transformer high-voltage side circuit breaker 1A-DL.

If within the delay time period of T6, for example, after the protection device of #2 grounding transformer receives the GOOSE message that the zero-sequence mutation protection of the same interval between this busbar and the adjacent busbar has acted and sent a trip command, and #2 grounding transformer Zero-sequence current mutation protection returns, that is, it is confirmed that the protection actions of other intervals have removed the fault, and #2 grounding change protection can return.

Before the aforementioned fault occurred, #2 grounding substation protection device, #2 neutral point protection device, line protection device for section I and section II buses, substation substation protection device and capacitor protection device passed through A network, B network and GOOSE+ respectively. The SV network receives the GOOSE message that the section breaker FDL is closing, the GOOSE message that #1 transformer low-voltage side circuit breaker 1B-DL is closing, and the #2 transformer low-voltage side circuit breaker 2B-DL is closing. The GOOSE message information of the first place, the GOOSE message information of the #1 grounding transformer circuit breaker 2DL in the second place, and each protection device has completed the operation preparation.

State 6: #1 transformer low-voltage side circuit breaker 1B-DL is closing, #2 transformer low-voltage side circuit breaker 2B-DL is closing, section interval circuit breaker FDL is closing, #1 grounding transformer circuit breaker 2DL is separating position, #2 grounding transformer circuit breaker 6DL is in the closed position, that is, #1 main transformer is running with 2 sections of 10kV bus and only #2 grounding transformer is in the running position.

When the zero-sequence current transformer 11 connected to the line protection device (or substation transformer protection device or capacitor protection device) is connected to any position close to the busbar side and a permanent fault occurs on the busbar side of the transformer, the action process at this time is as follows:

The zero-sequence voltage of the power distribution system rises. When the preset voltage threshold is reached, the zero-sequence current mutation calculation function of the line protection device (or substation transformer protection device or capacitor protection device) enters the start-up preparation state. When the line protection device (or substation transformer protection device or capacitor protection device) through the aforementioned A network, B network and GOOSE+SV network, the neutral point small resistance input from #2 neutral point protection device is received (that is, the circuit breaker DL is closed) ) after the GOOSE message, start to calculate the zero-sequence current mutation amount, but in this case the zero-sequence current does not pass through the zero-sequence current transformer 11 connected to the line protection device (or station transformer protection device or capacitor protection device), Therefore, the zero-sequence current obtained by the line protection device (or substation transformer protection device or capacitor protection device) does not change, that is, the ratio of the change value of the zero-sequence current to the initial value cannot reach the preset ratio range, so the line protection device (or Substation transformer protection device or capacitor protection device) will not send the GOOSE message that the zero-sequence current mutation protection has started in this interval. When the zero-sequence voltage of the power distribution system decreases and is lower than the preset voltage threshold, the zero-sequence current mutation The compute function exits the active state.

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the #2 neutral point protection device will input the small resistance of the neutral point after the second preset delay time T2 (that is, put the circuit breaker DL into position), At the same time, the information of changing the position of the input circuit breaker DL from the position to the position is sent to the busbar grounding change protection device and other protection devices (including the aforementioned line protection device) through the A network, B network and GOOSE+SV network in the form of GOOSE messages. , Capacitor protection device, station transformer protection device, etc.).

At the same time, when the zero-sequence voltage of the power distribution system rises to the preset voltage threshold, the zero-sequence current mutation calculation function of the #2 grounding substation protection device enters the start-up preparation state. After receiving the GOOSE message from the neutral point protection device for switching on the neutral point small resistance (that is, switching on the circuit breaker DL and closing the position), the calculation of zero-sequence current mutation is started. When the ratio of the change value of the zero-sequence current to the initial value reaches the preset ratio range, if the #2 ground change protection device does not pass the aforementioned A network, B network and GOOSE+SV network receive the GOOSE message that the zero-sequence mutation protection has been started from this bus and other intervals of the adjacent bus (line protection device or station transformer protection device or capacitor protection device), it is considered to be other If the zero-sequence current transformer 11 of the interval is permanently faulted near the busbar side or the busbar side of the transformer, etc., the #2 grounding transformer protection device will continue to trip the #1 transformer low-voltage side open circuit after the sixth preset delay time T6 The circuit breaker 1B-DL jumps off the #1 transformer high voltage side circuit breaker 1A-DL after the seventh preset delay time T7.

Specifically, if the #1 grounding transformer protection device receives the low-voltage side circuit breaker 1B-DL from the low backup protection device of the #1 transformer through the aforementioned A network, B network and GOOSE+SV network within the time period T6-T7 The GOOSE message of bit-to-bit change, and the zero-sequence current mutation protection of #1 grounding transformer returns, that is, it is confirmed that the low-voltage side of #1 transformer has acted and the fault has been removed, and the protection of #1 grounding transformer can return, and no longer Jump off the #1 transformer high voltage side circuit breaker 1A-DL; if the #1 grounding transformer protection device does not receive the low backup protection device of the #1 transformer within the time period T6-T7 without the aforementioned A network, B network and GOOSE+SV network The GOOSE message sent by the low-voltage side circuit breaker 1B-DL from close to position, or the zero-sequence current mutation protection of #1 grounding change does not return, that is, confirm that #1 transformer low-voltage side circuit breaker 1B-DL fails. Action requires #1 transformer high voltage side circuit breaker 1A-DL to cut off the fault. At this time, #1 grounding transformer protection device controls to trip #1 transformer high voltage side circuit breaker 1A-DL. (Note: The reason for not choosing to jump the segmental bay circuit breaker FDL is because if it is tripped, it will lose the grounding transformer of the power distribution system, and the power system does not allow operation without a grounding transformer)

It is understandable that at this time, the #2 grounding substation protection device cannot distinguish whether it is a fault in the bus area of section I or section II, so the #2 grounding substation protection device needs to trip the low-voltage side or high-voltage side circuit breaker of #1 transformer , in order to isolate the fault and restore the normal power supply of the power distribution system.

Before the aforementioned fault occurred, #2 grounding substation protection device, #2 neutral point protection device, line protection device for section I and section II buses, substation substation protection device and capacitor protection device passed through A network, B network and GOOSE+ respectively. The SV network receives the GOOSE message that the section breaker FDL is closing, the GOOSE message that #1 transformer low-voltage side circuit breaker 1B-DL is closing, and the #2 transformer low-voltage side circuit breaker 2B-DL is closing. The GOOSE message information of the first place, the GOOSE message information of the #1 grounding transformer circuit breaker 2DL in the second place, and each protection device has completed the operation preparation.

Of course, the present invention does not limit the specific values of the above preset delay times. This embodiment adopts the method of sudden change to determine the fault location. Compared with the method of using a fixed preset value, it can avoid the situation that the preset value cannot be reached when the high-impedance grounding occurs as far as possible, and the reliability is high; and this embodiment For example, the zero-sequence current transformer and three-phase current transformer can be detected, and whether the aforementioned two transformers are faulty can be found in time, avoiding the occurrence of inaccurate detection caused by ground fault detection under fault conditions.

It should be noted that in this specification, relative terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations Any such actual relationship or order exists between. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above description of the disclosed embodiments enables those skilled in the art to realize or use the utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. the fault protection system for distribution system, it is characterised in that including:

The ground connection being connected with the control end of ground connection transformer breaker becomes protection device；The height being connected with main transformer high-pressure side chopper Reserve protection；The low reserve protection being connected with main transformer low-pressure side chopper；It is connected with section gap chopper Sectionalised protection device；Protection device is become respectively with several the connected stations of end that control of corresponding station transformer breaker；Point Several line protective devices not being connected with the control end of corresponding line-breaker；Respectively with corresponding capacitor breaker Control end be connected several capacitor protectors；

That be connected with the control end putting into chopper of neutral point small resistor, for when the zero sequence judging on coupled bus Voltage controls the neutral point protection dress of described input breaker closing after reaching predetermined voltage threshold and continuing the first Preset Time Put；Wherein, described small resistor is in parallel with arc suppression coil；

Described ground connection become protection device, described neutral point protecting device, several described stations change protection device, described in several Line protective devices, several described capacitor protectors, described low reserve protection, described high reserve protection with And described sectionalised protection device is connected with the A net of station level in described distribution system and B net and Tong Bu setting network respectively, And each protection device opening by the chopper of described A net and the described B mutual respective running status of net and each connection Closed state.

System the most according to claim 1, it is characterised in that described ground connection becomes protection device, described neutral point protection dress Put, several described stations become protection device, several described line protective devices, several described capacitor protectors, Described low reserve protection, described high reserve protection and described sectionalised protection device the most respectively with described distribution system The GOOSE+SV net of middle process layer is connected.

System the most according to claim 1 and 2, it is characterised in that described ground connection become protection device respectively with described main transformer The control end of depressor low-pressure side chopper, described main transformer high-pressure side chopper and described section gap chopper is connected； Described ground connection becomes protection device and the most directly controls described main transformer low-pressure side chopper, described main transformer high-pressure side open circuit Device and the open and-shut mode of described section gap chopper.

System the most according to claim 1 and 2, it is characterised in that described low reserve protection and described main transformer The control end of low-pressure side chopper is connected；

Described high reserve protection is connected with the control end of described main transformer high-pressure side chopper；

Described sectionalised protection device is connected with the control end of described section gap chopper；

Described ground connection becomes protection device and controls signal to described low back-up protection dress accordingly by coupled network transmission Put or described high reserve protection or described sectionalised protection device, and protected by described low reserve protection or described high standby Protection unit or described sectionalised protection device control the opening and closing of the chopper of self correspondence according to the described control signal received State.

System the most according to claim 1 and 2, it is characterised in that described ground connection becomes protection device, several described stations are used Become protection device, several described line protective devices and several described capacitor protectors respectively with a zero sequence Current transformer is connected；

Described station includes in becoming protection device, described line protective devices and described capacitor protector respectively:

For triggering zero-sequence current Sudden Changing Rate when the residual voltage on coupled bus reaches described predetermined voltage threshold The first zero-sequenceprotection module that computing module starts；

For when being received the message of described input breaker closing by network, calculating coupled described zero-sequence current Before the zero-sequence current on transformer changing value before and after described neutral point small resistor puts into puts into described neutral point small resistor Whether the ratio of the initial value of zero-sequence current presets ratio range beyond corresponding, if it is, trigger the first zero-sequence current protection The described zero-sequence current Sudden Changing Rate computing module of module；

Protect the message extremely connected network of action for sending zero-sequence current Sudden Changing Rate, and control coupled breaking The described first zero-sequence current protection module that road device disconnects；

Described ground connection becomes protection device and specifically includes described first zero-sequenceprotection module, described zero-sequence current Sudden Changing Rate computing module And for selecting according to the running status of each protection device received from network and the open and-shut mode of each chopper Corresponding predetermined control strategy controls the second zero-sequence current protection module that corresponding chopper disconnects；

Described neutral point protecting device specifically includes for reaching described default electricity when the residual voltage on coupled bus The second zero-sequenceprotection module of described input breaker closing is controlled during pressure threshold value.

System the most according to claim 5, it is characterised in that become protection device described ground connection, several described stations are used Become protection device, several described line protective devices and several described capacitor protectors respectively with a three-phase When current transformer is connected, described ground connection becomes protection device, described station becomes protection device, described line protective devices and institute The most also include in stating capacitor protector:

For when receiving, by network, the message that described input chopper does not puts into, compare the described three-phase being connected with self Whether the self-produced zero-sequence current on current transformer is more than the actual measurement zero sequence on the described zero sequence current mutual inductor being connected with self Electric current and more than the first pre-set current value, if it is, send the message of described threephase current transformer fault to the most connected First judge module of network；

For when receiving, by network, the message that described input chopper puts into, comparing the described three-phase electricity being connected with self Whether the self-produced zero-sequence current on current transformer is more than the actual measurement zero sequence electricity on the described zero sequence current mutual inductor being connected with self Stream and described self-produced zero-sequence current are less than the 3rd pre-set current value more than the second pre-set current value and described actual measurement zero-sequence current, as Fruit is, sends the message extremely described network of described zero sequence current mutual inductor fault, and by the reality on described threephase current transformer Survey zero-sequence current as self correspondence described zero-sequence current Sudden Changing Rate computing module calculate time zero-sequence current second judgement Module.