WO2014089958A1

WO2014089958A1 - Distribution network failure isolation and recovery method realizing penetration distributed generation

Info

Publication number: WO2014089958A1
Application number: PCT/CN2013/076697
Authority: WO
Inventors: 柳劲松; 周健; 时珊珊; 徐琴
Original assignee: 上海市电力公司; 华东电力试验研究院有限公司; 国家电网公司
Priority date: 2012-12-10
Filing date: 2013-06-04
Publication date: 2014-06-19
Also published as: CN103022994B; CN103022994A

Abstract

A distribution network failure isolation and recovery method realizing penetration distributed generation, which belongs to the field of distribution network operation management.It is characterized in that a failure isolation and recovery process of a distribution network containing distributed generation is realized based on an intelligent distributed feeder automation mode, the degree of intelligentization is high in the failure clearance and recovery process thereof, the judgement is rapid and accurate, the logical conditions can be modified or supplemented according to the actual topological structure of a power grid, the whole control mode is based on the existing device but not limited by the existing device, and along with the continual upgrading of a smart power grid device, various action logical conditions can be modified and supplemented according to the actual topological structure of the power grid, being convenient for computer simulation and failure power flow analysis, and providing a guarantee for dispatching and operation management of a distribution network containing penetration distributed generation.This can be widely applied to the fields of dispatching, operation management and failure emergency treatment of smart power grids.

Description

Description of a distribution network fault isolation and recovery method for implementing distributed power supply

The invention belongs to the field of operation and management of a distribution network, and in particular relates to a method for fault isolation and recovery for a distribution network. Background technique

Since the 1990s, distributed power generation has developed rapidly. Many countries in the world have made renewable energy the basis of energy policy. The development of distributed power generation has become the benchmark for sustainable development in all countries of the world.

The development of distributed power generation in China is relatively late. In recent years, the distributed power generation of Haojie Energy has only begun. In recent years, China's distributed power sources have developed rapidly.

At present, the rapid development of distributed power sources poses severe challenges to national support policies and network access support.

As a large number of distributed power generation access to the urban distribution network, it will bring many new technical and management problems such as power quality, impact on relay protection, short-circuit current distribution, and island operation. When the distributed power supply penetrates into the 10kV feeder, the original feeder automation solution cannot handle the feeder fault problem. When a fault occurs on the feeder, the substation's outlet power supply and the distributed power supply on the feeder will contribute to the fault current at the fault point. Therefore, the fault current is bidirectional, so the fault detection mechanism of the distribution network terminal in the original feeder automation should be re Design; On the other hand, in the process of fault handling and recovery, the distributed power supply to the power supply service brings many problems to be considered from both technical and management aspects.

Feeder automation is an important part of distribution network automation. It can quickly isolate faults, restore power supply in non-faulty areas, and improve the reliability of distribution network.

At present, the main focus of domestic and foreign research is on the impact of distributed power supply on distribution network protection and the change of distribution network power. The research on feeder automation solutions with DG (distributed dgeneration) is relatively rare.

In China, Yanshan University scholars Lu Zhigang and Dong Yuxiang published an article "Distribution Strategy for Distribution Network with Distributed Power Supply" in the first issue of "Power System Automation" in 2007, and proposed a new fault recovery strategy considering DG. In the conscious island operation mode, using the improved forward-forward method to contain The distribution network of DG calculates the distribution network flow, and the fault recovery steps and example simulation of the distribution network considering DG are given.

The announcement date is January 19, 2011, the Chinese invention patent with the authorization announcement number CN 101552461B, and discloses a "including distributed power supply distribution network protection method", which has one or one for the distribution network bus. In the case of the distributed power supply above, in the upstream area of the distributed power distribution network, the direction longitudinal protection device is installed, and the time-limited overcurrent protection mode with directional components is used in the area; Where there is at least one distributed power source in the network non-busbar, in the upstream area of the distributed power distribution network, the direction longitudinal protection device is installed, and the overcurrent protection device is installed in the downstream area, and The entire area uses inverse time overcurrent protection. It can be seen that the technical solution mainly improves the conventional current protection configuration to ensure reliable removal of the fault of the DG distribution system. Because it is limited to the traditional conventional relay protection system, and its invention aims to quickly remove the faulty distributed power supply, it does not observe and solve the problem from the perspective of the entire power distribution network, and lacks overall power grid scheduling and management. Vision, can not adapt to the current level of operation, scheduling and management of the intelligent distribution network.

As for the feeder automation (FA) solution with distributed power supply, there is no development application, and there is no application example in the power supply company. Summary of the invention

The technical problem to be solved by the present invention is to provide a distribution network fault isolation and recovery method for implementing a distributed distributed power source, which is based on an intelligent distributed feeder automation mode to implement fault isolation of a distribution network including distributed power sources. The recovery process, the degree of intelligence in the troubleshooting and recovery process is high, the judgment is rapid and accurate, and the logic conditions can be modified and supplemented according to the actual topology of the power grid to provide scheduling and operation management for the distribution network including distributed power sources. Guaranteed.

The technical solution of the present invention is: A distribution network fault isolation and recovery method for implementing a distributed distributed power source, including fault isolation and recovery of a distribution network, characterized in that -

1-1) The distribution network fault isolation and recovery method is based on an intelligent distributed feeder automation mode to realize distribution network fault isolation and recovery of a distributed distributed power source;

1-2) After satisfying the "fault start" condition, each FA intelligent substation controller is grouped into a queue for continuous monitoring, and the voltage, switch position, fault status of the feeder line are shared between the FA intelligent substation controllers, Information such as the access status of the distributed power source;

1-3) The feeder switch controller where the fault occurs is judged after the relevant signal is learned, and the switch before and after the fault point performs a "trip" action, thereby automatically cutting off the fault; 1-4) Through the peer-to-peer communication between the FA intelligent substation controllers, other switches in the group get information about which switch has been cut off;

1-5) According to the fault isolation logic and fault recovery logic, each switch will automatically decide whether to perform the "closed" operation according to its position in the feeder, and quickly restore the power supply to the normal interval of the line according to the "recovery process";

1-6) If the grid connection conditions are met, the distributed power supply automatically performs the "synchronous grid connection" operation;

1-7) Perform post-fault processing operations.

Wherein, the "fault start" condition is that the relay protection signal of the outlet circuit breaker and the "opening" status signal are received, and the switch is in the "pressure loss" state, waiting for the first time setting value, ensuring distributed The power is connected to the network.

The first time set value described above is 5 seconds.

After the fault occurs, the FA intelligent substation controller starts from the outlet circuit breaker, notifies the switch status and the fault information to the relevant switch, determines the fault position by the controller, and isolates the fault point before and after the switch, and is connected to the distributed power source. The switch transmits the state of the grid point switch to the control unit of the outlet breaker.

The peer-to-peer communication described is realized by the communication network of each FA intelligent substation controller and the switch position status message.

Specifically, the fault isolation logic thereof is

6-1) If a switch receives a fault message and is in the "loss of voltage" state, the switch is opened and the fault message is transmitted to the next level;

6-2) From the exit circuit breaker, all switches are tripped in sequence before the tie switch. 6-3) If the switch does not move, it cannot be tripped, it is recorded as "rejection" status, and the "rejection" status is notified to the adjacent switch, and the fault processing is terminated;

6-4) If the switch communication of the next stage is unsuccessful, record the switch with poor communication around, and the fault processing is terminated.

The recovery process described therein begins simultaneously with the exit breaker and the tie switch; the fault recovery logic is

7-1) For outlet circuit breakers and tie switches -

A. If a switch is an outlet breaker and there is no overcurrent switch around, the outlet breaker is closed;

There is an overcurrent switch around, and there is a disconnect switch around, the circuit breaker will close, and the adjacent switch will be notified after the action is successful; B. If a switch is a tie switch and there is an overcurrent switch around, the tie switch remains open;

If there is no overcurrent switch around, and there is a disconnect switch around, the tie switch will close, and after successful, notify the adjacent switch to the direction of the exit breaker;

7-2) For other switches:

If a switch successfully trips and receives an adjacent switch to successfully recover the message, it enters the recovery process; there is a disconnected switch around the switch, which is itself a voltage-loss switch and there is no overcurrent, if the surrounding is a loss of voltage but the flow switch Or if there are two overcurrent switches or the switch itself is an end switch that directly connects the load, then the switch will close;

There is a disconnect switch around the switch, which is a loss-of-voltage switch but over-current. If there are two over-current switches around, the switch will close, otherwise it will remain separated;

The surrounding switches must be notified when each switch is closed to prevent the ring from running.

The grid-connected condition is the grid-connected condition of the conventional grid power generation equipment. Compared with the prior art, the advantages of the present invention are -

1. For the fault isolation and recovery process of the distribution network with distributed power supply, the intelligent distributed feeder automation mode is introduced, which has high intelligence in the troubleshooting and recovery process, and the judgment is rapid and accurate. The logic conditions can be based on the grid. The actual topology is modified and supplemented;

2. The entire control mode is based on existing equipment and is not limited by existing equipment. With the continuous upgrading of smart grid equipment, the control strategy can be continuously adjusted and supplemented, regardless of the specific structure of the hardware;

3. Various operational logic conditions can be modified and supplemented according to the actual topology of the power grid, which facilitates computer simulation and fault flow analysis, and provides guarantee for dispatching and operation management of distribution network including infiltrated distributed power. BRIEF abstract

Figure 1 is a block diagram showing the flow of the method of the present invention;

Figure 2 is a block diagram showing the flow of calculating the load of adjacent feeder segments;

Figure 3 is a block diagram showing the flow of finding a contact switch;

Figure 4 is a block diagram showing the flow of the fault start condition;

Fig. 5 is a schematic diagram showing the positional relationship of switches in a special case. detailed description

The invention will be further described below in conjunction with the drawings and embodiments.

In Fig. 1, the present invention provides a distribution network fault isolation and recovery method for implementing a distributed distributed power source, including fault isolation and recovery of a distribution network, and the technical solution of the invention lies in that -

1-1) The distribution network fault isolation and recovery method is based on intelligent distributed feeder automation mode to realize distribution network fault isolation and recovery of distributed power supply-

1-3) When the faulty switch is informed of the "overcurrent" or "loss of voltage" signal, the fault is judged. The relay system sends a "jump" signal, and the switch performs the "jump" action, thus causing the fault. Automatic resection;

1-4) Through the peer-to-peer communication between the FA intelligent substation controllers, other switches in the group get information about which switch has been cut off;

1-5) According to the fault isolation logic and fault recovery logic, each switch will automatically decide whether to immediately "trip" according to its position in the system to cut off the fault, quickly isolate the fault point, or perform a "closed" operation, press " The recovery process "rapidly restores power to the normal section of the line;

1-7) Perform post-fault processing operations.

The "fault start" condition is that the relay protection signal and the "open" status signal of the outlet circuit breaker are received, and the switch is in the "pressure loss" state, waiting for the first time setting value (5 seconds) , to ensure that distributed power is connected to the grid.

After the fault occurs, the FA intelligent substation controller starts from the outlet circuit breaker, transmits the switch state and the fault information backward, and the switch is sequentially isolated. The switch connected to the distributed power source transmits the state of the grid point switch to the exit. The control unit of the circuit breaker.

The peer-to-peer communication described is realized by the communication network of each FA intelligent substation controller and the switch position status message. Feeder automation (FA) refers to the automation of the feeder line between the substation outlet and the user's electrical equipment. The content can be summarized into two aspects: First, user detection, data measurement and operation optimization under normal conditions; It is fault detection, fault isolation, transfer and recovery power control in the event of an accident.

Feeder automation is an important part of distribution network automation. To achieve feeder automation, you need Reasonable distribution network structure, with ring network power supply conditions; The operation mechanism of each ring network switch, load switch and terminal switch in the final stage must have remote operation function; the ring network switch cabinet must have reliable switch operation power supply and A working power supply for FTU (Feeder Terminal Unit) and communication equipment; a reliable communication system that is not affected by the external environment.

It can be known from the above that the basic logical operation process of FA is as follows:

1. Initialize, read the necessary information of the switch and adjacent switches;

2. Calculate the load of adjacent feeder segments;

3. Determine whether the switch is a tie switch;

4. Fault starting conditions;

5. Fault isolation process;

6. Failure recovery process;

7. Processing after failure.

Specifically, the detailed steps are as follows:

1. Initialization:

Obtain the parameter information of the DG in the unit and adjacent to the unit and directly connected to the DG.

2. Calculate the load of the feeder segment - Calculate the load of each feeder segment to provide a transfer basis for recovery;

In the actual module, the load is measured by the current;

Each switch sets its own rated current according to the daily operating state;

The load value used in the fault recovery is the load value before the fault, and the power flow calculation value can be used instead in the simulation program.

The above steps and logical relationships are shown in Figure 2.

3. Find the contact switch:

The tie switch and the outlet breaker are the starting points for recovery;

The calculation of the contact switch is repeated at regular intervals;

Consider the case of simultaneously exporting a circuit breaker;

Consider the case of multiple power supplies.

The above steps and logical relationships are shown in Figure 3.

4. Fault start condition - The fault must have a start condition, otherwise the normal switch will be closed and the repair will be treated as a fault. After the fault occurs, starting from the outlet circuit breaker, the switch state and the fault information are transmitted backwards, the switches are sequentially isolated, and the switch connected to the distributed power source transmits the state of the grid-connected switch to the control unit of the outlet circuit breaker;

Start condition: Receive the protection signal and sub-state of the outlet breaker, and the switch loses pressure, wait for a period of time (5S) to ensure that the distributed power supply is connected to the grid.

The above steps and logical relationships are shown in Figure 4.

5. Fault isolation logic - The isolation logic is detailed as follows - If a switch receives a fault message and is in a state of loss of voltage (to prevent the normally functioning switch from being tripped by the fault signal); then the switch is opened and the fault message is directed Pass the next level.

If the switch is rejected, it cannot be tripped, recorded as a reject status, and the rejection status is notified to the adjacent switch.

If the next level of switch communication is unsuccessful, record a switch with poor communication around.

From the point of view of the isolation process, all switches are tripped in sequence from the exit breaker to the tie switch.

6. Failure Recovery Logic - The recovery algorithm is detailed below:

The recovery process begins simultaneously with the outlet breaker and the tie breaker.

A. For the outlet circuit breaker and the tie switch - Al, if one switch is the outlet circuit breaker - there is no overcurrent switch (ie the short circuit occurs on the outlet side of the circuit breaker), then the circuit breaker will not close. There is overcurrent around Switch, and there is a disconnect switch (preventing the ring network), then the circuit breaker will close, and the adjacent switch will be notified after the action is successful;

A2, if a switch is a tie switch:

There is an overcurrent switch (ie, the short circuit occurs on the side of the tie switch), then the tie switch keeps open; there is no overcurrent switch around, and there is a disconnect switch (preventing the ring net), then the tie switch will close and succeed Notifying the proximity switch in the direction of the backward outlet circuit breaker;

B, for other switches:

If a switch successfully trips and receives a successful recovery message from the adjacent switch, it enters the recovery process; there is a disconnected switch around the switch (to prevent closed-loop operation after opening and closing), itself is a loss-of-voltage switch and there is no overcurrent, if There are pressure loss around but no flow switch or two overcurrent switches or this switch As an end switch that directly connects the load, the switch will close;

There is a switch around the switch (to prevent closed-loop operation after opening and closing), which is a loss-of-voltage switch but over-current. If there are two over-current switches around, the switch will close, otherwise it will remain separated; When the gate is closed, the surrounding switch must be notified to prevent the loop from running, considering the load transfer capability of the opposite power source;

Abnormal situation handling -

C, switch "rejection" situation analysis - If the switch itself is a reject switch, run the fault recovery logic, determine the action that you want to complete, and then pass the reject information and the action you want to complete to the adjacent switch;

There is a reject switch adjacent to the switch, and a recovery signal is received to satisfy the closing condition.

If the reject switch itself needs to be closed, the switch performs a "closed" operation;

If the reject switch itself needs to trip, the switch performs a "disconnect" operation;

D. Analysis of switch rejection and communication failure - The reject switch cannot be closed because it cannot be closed, and the recovery process ends.

If there is a switch with poor communication around, the switch state remains unchanged.

For the area where the power is lost before the fault, the fault cannot be changed during the fault handling. For example, in the case shown in Figure 5, the b and c switches remain in the "open" state before the fault, and cannot be closed during the recovery process after the fault. To prevent closing under inspection.

If the grid connection conditions are met, the distributed power supply automatically performs "synchronous grid connection" operation. The automatic grid-connected condition is the grid-connected condition of the conventional grid power generation equipment, which is a conventional technical means and will not be described here. The above embodiments are only intended to explain and explain the present invention, and are not intended to limit the technical solutions of the present invention; those skilled in the art will recognize that the above implementations are within the spirit of the present invention. Variations and modifications of the examples will fall within the scope of protection claimed in the claims of the present invention. Industrial applicability

Since the technical solution of the present invention is based on an intelligent distributed feeder automation mode to implement a fault isolation and recovery process of a distribution network including a pervasive distributed power source, the degree of intelligence in the troubleshooting and recovery process is high, and the judgment is rapid and accurate, and logic Conditions can be modified and supplemented according to the actual topology of the grid. The entire control mode is based on existing equipment and is not limited by existing equipment. Upgrades, control strategies can be continuously adjusted and supplemented to provide assurance for the dispatching and operation management of distribution networks that contain distributed power.

The invention can be widely used in the fields of scheduling, operation management and fault emergency treatment of smart grids.

Claims

Claim

1. A method for fault isolation and recovery of distribution networks that implements infiltrated distributed power sources, including fault isolation and recovery of distribution networks, characterized by -

1-3) The feeder switch controller where the fault occurs is judged after the relevant signal is learned, and the switch before and after the fault point performs the "trip" action, thereby automatically cutting off the fault;

1-7) Perform post-fault processing operations.

2. The method for fault isolation and recovery of a distribution network implementing a pervasive distributed power source according to claim 1, wherein said "fail-start" condition is a relay protection signal and "opening" of the outlet circuit breaker. "Status signal, and this switch is in the "loss of voltage" state, waiting for the first time set value, to ensure that the distributed power supply is connected to the grid.

3. A distribution network fault isolation and recovery method for implementing a pervasive distributed power supply according to claim 2, wherein said first time setting is 5 seconds.

4. The method for distributing fault isolation and recovery of a distribution network according to claim 1, wherein after the fault occurs, the FA intelligent substation controller starts from an outlet circuit breaker and switches states. And the fault information is notified to the relevant switch, the fault location is determined by the controller, the switch is isolated before and after the fault point, and the switch connected to the distributed power source transmits the state of the grid switch to the control unit of the outlet breaker.

5. The method for distributing fault isolation and recovery of a distribution network according to claim 1, wherein said peer-to-peer communication passes through a communication network and a switch position of each FA intelligent substation controller. Status message is implemented.

6. The distribution network fault isolation and recovery method for implementing a pervasive distributed power supply according to claim 1, wherein said fault isolation logic is

7. The method of claim 1, wherein the recovery process begins simultaneously with an outlet circuit breaker and a tie switch;

7-1) For outlet circuit breakers and tie switches -

If there is an overcurrent switch around, and there is a disconnect switch around, the circuit breaker will close, and the adjacent switch will be notified after the action is successful;

B. If a switch is a tie switch and there is an overcurrent switch around, the tie switch remains open;

7-2) For other switches:

8. The distribution network fault isolation and recovery side of the distributed distributed power source according to claim 1 The method is characterized in that the grid-connected condition is a grid-connected condition of a conventional grid power generating device.