CN104135079A - Failure processing method for intelligent power distribution network comprising distributed power supply - Google Patents

Abstract

The invention relates to a fault processing method for an intelligent distribution network containing a distributed power supply, comprising the following steps: (1) a fault monitoring program in a master station of distribution automation monitors all remote signaling and displacement information in the distribution network, and screens the existing The fault signal is detected by the fault analysis program according to the downstream protection signal; (2) fault isolation is carried out according to the principle of the minimum load loss; (3) the energy management system in the distribution automation master station combines the current operating status of the distributed power supply, according to Different constraints and objective functions formulate a reasonable fault recovery strategy, and send it to the coordination control layer for fault recovery. The present invention performs fault location according to all the remote signal displacement information in the distribution network, performs fault isolation according to the principle of the minimum load power loss, and formulates a reasonable recovery strategy, thereby solving the problem of fault location after the introduction of distributed power into the distribution network, The problem of fault isolation and fault recovery effectively improves the reliability of feeder automation.

Description

Fault handling method for smart distribution network with distributed power

technical field

The invention belongs to the technical field of intelligent distribution network, in particular to a fault processing method for an intelligent distribution network including distributed power sources.

Background technique

Feeder automation can monitor the operating status of the distribution network and its equipment in real time, and provide a basis for further strengthening the construction of the power grid and gradually realizing distribution automation. It is an important function of the distribution management system. When a fault occurs in the distribution network, the feeder automation can quickly detect the faulty area, automatically isolate the faulty area, and restore the power supply of users in the non-faulty area in time, thus shortening the power outage time of the user, reducing the power outage area, and improving the reliability of power supply.

After the distributed power supply is connected to the distribution network, the structure and operation of the distribution system will be changed, and the distribution network will change from a strictly vertical radial network to a horizontal network with power supply. When the number and capacity of distributed power sources connected to the distribution network reach a certain level, the traditional feeder automation technology will no longer be applicable. For the situation where the distributed power supply is connected to the feeder, when a fault occurs in a certain area, in addition to the short-circuit current supplied by the main power supply in the main power supply side terminal of the area, the terminal connected to the distributed power supply in the area will also flow The short-circuit current supplied by the corresponding distributed power supply. If there is a large difference between the short-circuit current supplied by the main grid power supply and the distributed power supply, the short-circuit current can be distinguished from the short-circuit current supplied by the main grid power supply and the distributed power supply by increasing the short-circuit current reporting threshold. position. When the short-circuit current supplied by the main network power supply and the distributed power supply is not much different, it is difficult to distinguish, and fault location may cause misjudgment by relying on the traditional fault location principle. Therefore, under different fault scenarios, it is an inevitable trend for the development of feeder automation to realize the accurate fault location of the distribution network with distributed power. issues that need resolving.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a reasonable design, fast, accurate, stable and reliable intelligent distribution network fault handling method with distributed power.

The present invention solves its technical problem and realizes by taking the following technical solutions:

A fault handling method for an intelligent distribution network including distributed power sources, comprising the following steps:

(1) Fault location processing steps: the fault monitoring program in the distribution automation master station monitors all the remote signal displacement information in the distribution network, screens the fault signals existing in it, and the fault analysis program performs fault location according to the downstream protection signals;

(2) Fault isolation processing steps: perform fault isolation according to the principle of minimum load loss;

(3) Fault recovery processing steps: The energy management system in the distribution automation master station combines the current operating status of the distributed power supply, formulates a reasonable fault recovery strategy according to different constraints and objective functions, and sends it to the coordination control layer for execution.

Moreover, the fault location processing, fault isolation processing, and fault recovery processing also include processing procedures of fault information display, fault isolation processing result display, and fault recovery processing result display.

Moreover, the fault isolation process is carried out in an automatic or interactive manner. In the automatic mode, the system automatically executes the fault isolation strategy according to the fault processing plan, and can display fault isolation information and processing process information on the display interface; In the interactive mode, the fault analysis conclusion is given in the form of a display interface, and the dispatcher can execute the fault isolation strategy step by step on the display interface, and feedback the execution status of each step.

Moreover, the fault recovery process is carried out in an automatic or interactive manner. In the automatic mode, the system automatically executes the fault recovery strategy according to the fault processing plan, and displays the recovery plan and processing process information on the interface. In the interactive mode Next, the fault analysis conclusion is given in the form of an interface, and the dispatcher can execute the fault recovery strategy step by step on the display interface, and feedback the execution status of each step in time.

Moreover, the fault recovery strategy includes two schemes: one is to find a suitable transfer line within the contact range of the distribution network and use the main grid power supply first; the other is to carry out distributed power supply screening, distributed power supply boundary division, Island load distribution and distributed power generation forecasting and load forecasting are used to build islands.

Moreover, in the process of fault recovery, the cooperation of distributed power off-grid characteristics and reclosing is used to eliminate the influence of distributed power in short-circuit current, including the following processing procedures:

(1) The delay time of substation reclosing is increased to 2.5s-3.5s;

(2) The overcurrent signal sent to the power distribution terminal is not held, or the signal holding time is shortened to within 1s;

(3) Increase the superposition analysis function of the two overcurrent signals.

Advantage and positive effect of the present invention are:

1. According to the characteristics of the intelligent distribution network, the present invention performs fault location according to all the remote signal displacement information in the distribution network, performs fault isolation according to the principle of minimum load loss, and formulates a reasonable recovery strategy, thus solving the problem of power distribution. The problems of fault location, fault isolation and fault recovery after the introduction of distributed power into the network have effectively improved the reliability of feeder automation.

2. The present invention uses an automatic or interactive method to perform fault isolation and fault recovery, which shortens the user's power outage time, reduces the power outage area, and improves user satisfaction.

3. The present invention can monitor the operating state of the distribution network containing distributed power sources in real time, provide a basis for further strengthening the construction of the power grid and gradually realize distribution automation, and has practical significance for promoting the application of distribution automation.

Description of drawings

Fig. 1 is a process flowchart of the present invention.

Detailed ways

Embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings:

A fault handling method for an intelligent distribution network with distributed power sources, as shown in Figure 1, comprising the following steps:

(1) Fault location processing steps

After the distributed generation is connected to the distribution network, the distribution network changes from the original radial structure to a multi-source network structure, which threatens the original protection of the distribution network and may lead to misjudgment of faults. In order to realize the accurate location of faults in the distribution network with distributed generation, on the basis of analyzing the impact of distributed generation on distribution network under different fault scenarios, the following conclusions are drawn: The power supply radius of the connected distribution line is relatively long. In the case of a fault, the short-circuit current provided by the distributed power supply to the distribution network is likely to affect the overcurrent signal action on the line switch. It is required to install direction protection to send direction signals to the energy management system. .

In this step, the fault monitoring program in the distribution automation master station monitors all the remote signal displacement information in the distribution network, and screens possible fault signals in it according to the starting conditions. Once a fault is caught, the fault analysis is started and the The fault analysis program performs fault location based on downstream protection signals.

When performing fault location, the distribution automation host starts the fault processing program based on the fault information detected by each distribution terminal or fault indicator, combined with the fault information such as relay protection signals and switch trip signals of the substation, and determines the type and occurrence of the fault. The corresponding power distribution single-line diagram is automatically released, and the fault area can be indicated on the display interface by means of network dynamic topology coloring. The results of troubleshooting can be displayed in various ways such as upper alarm window, graph coloring, and historical query. When performing fault isolation and fault recovery processing, interactive processing can be carried out according to the results of fault location.

(2) Fault isolation processing steps

Fault isolation analysis is carried out according to the principle of minimum load loss, that is, the analysis of the minimum isolation range is required. The fault isolation control is simple by using the principle of the minimum load loss, and has the least impact on the operation mode of the distribution network.

Fault isolation processing can be carried out in an automatic mode. In the automatic mode, the system automatically executes the fault isolation strategy according to the fault processing plan, and can display fault isolation information and processing information on the display interface.

Fault isolation processing can also be realized in an interactive way: in the interactive mode, firstly, the fault analysis conclusion is given in the form of a display interface, including fault location results, fault isolation schemes and other related information; the dispatcher can execute the fault step by step on the display interface Isolate policies and provide timely feedback on the execution status of each step.

(3) Fault recovery processing steps

Under the premise of ensuring the safe operation of the power system, the energy management system in the distribution automation master station combines the current operating status of distributed power sources (such as photovoltaic output, battery remaining capacity, etc.), according to different constraints and objective functions (such as the maximum load recovery Or the minimum number of switch operations, etc.) formulate a reasonable fault recovery strategy, and send it to the coordination control layer for execution.

The recovery strategy is essentially a network reconstruction that occurs after a fault. There are two main ways for distributed power to participate in fault recovery:

①Ensure the reliability of power supply for load transfer. Find a suitable transfer line within the contact range of the distribution network and give priority to the use of the main network power supply. This method can maximize the reliability of power supply, but the use of distributed power supply is limited.

②Use distributed power sources to build islands. This method requires distributed power screening, distributed power boundary division, island load distribution, distributed power generation forecasting and load forecasting. Make full use of distributed power to restore power to the island distribution network.

Fault recovery processing can be carried out in an automatic mode. In the automatic mode, the system automatically executes the fault recovery strategy according to the fault processing plan, and can display information such as the recovery plan and the processing process on the interface.

Fault recovery processing can also be implemented in an interactive manner: in the interactive mode, the fault analysis conclusion is first given in the form of an interface, including fault isolation schemes, upstream and downstream power supply restoration schemes and other related information; the dispatcher can press the steps on the display interface Execute fault recovery strategies, and be able to give timely feedback on the execution status of each step.

In the process of fault recovery, it is also possible to further use the cooperation of the off-grid characteristics of the distributed power supply and the reclosing switch to eliminate the influence of the distributed power supply in the short-circuit current. According to Q/GDW480-2010 "Technical Regulations on Connecting Distributed Power Sources to the Power Grid", distributed power sources without conscious islands must be disconnected from the power grid within 2 seconds after the feeder fails. Accordingly, the cooperation of distributed power off-grid characteristics and reclosing can be used to eliminate the influence of distributed power in short-circuit current. The specific processing methods are as follows:

(1) The delay time of substation reclosing is increased to 2.5s-3.5s.

Within 2s after the fault occurs, all distributed power sources on the feeder are disconnected from the grid. After the substation outlet circuit breaker trips, it will be reclosed after a delay of 2.5s-3.5s. If there is a permanent fault, the substation outlet circuit breaker will trip again. At this time, the fault information collected by the power distribution automation system for the second time eliminates the fault of the distributed power supply. Influence.

(2) The overcurrent signal sent to the power distribution terminal is not held, or the signal holding time is shortened to within 1s.

Existing power distribution terminals usually keep the over-current signal for a long time (several minutes or hours) for reasons such as reliable over-current signal transmission and line inspection, which will affect the reporting of the secondary over-current signal. The holding time of the overcurrent signal needs to be shortened or not held, but the reliable sending of the signal must be ensured.

(3) Increase the superposition analysis function of the two overcurrent signals

For the feeder automation of overhead lines, the fault handling function software of the main station of distribution automation needs to add the function of overcurrent signal superposition analysis. The master station superimposes and matches the overcurrent signals received twice before and after reclosing to locate and analyze the fault.

When the distributed power access capacity exceeds 25% of the line capacity, it is necessary to re-adjust the threshold value of the fault information reported by the power distribution terminal and increase the set value.

The above improvement strategy is applicable to the situation of accessing distributed power sources of any capacity, and it is not necessary to change the hardware of the distribution automation system, only a slight change in the fault handling application software is enough.

It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, so the present invention includes and is not limited to the embodiments described in the specific implementation, and those skilled in the art according to the technology of the present invention Other implementations derived from the scheme also belong to the protection scope of the present invention.

Claims (6)

1. containing an intelligent distribution network fault handling method for distributed power source, it is characterized in that, comprise the following steps:

(1) fault location treatment step: the failure monitoring program in power distribution automation main website is monitored all remote signalling displacement information in power distribution network, the fault-signal that screening wherein exists, carries out fault location by failure analysis program according to downstream guard signal;

(2) Fault Isolation treatment step: carry out Fault Isolation according to load dead electricity amount minimum principle;

(3) Petri Nets step: the EMS in power distribution automation main website, in conjunction with the current running status of distributed power source, is formulated rational fail-over policy according to various boundary conditions and target function, and be handed down to the execution of coordination key-course.

2. the intelligent distribution network fault handling method containing distributed power source according to claim 1, is characterized in that: described fault location is processed, Fault Isolation is processed and also comprise the processing procedure that fault message shows, Fault Isolation result shows and Petri Nets result shows during Petri Nets.

3. the intelligent distribution network fault handling method containing distributed power source according to claim 1 and 2, it is characterized in that: described Fault Isolation processing adopts automated manner to carry out or interactive mode is carried out, under automated manner, system automatically performs the Fault Isolation Strategy according to troubleshooting scheme, and can on display interface, show isolation information and the processing procedure information of fault; Under interactive mode, with the form of display interface, provide accident analysis conclusion, dispatcher can carry out the Fault Isolation Strategy by step on display interface, and feeds back the executing state of each step.

4. the intelligent distribution network fault handling method containing distributed power source according to claim 1 and 2, it is characterized in that: described Petri Nets adopts automated manner to carry out or interactive mode is carried out, under automated manner, system automatically performs fail-over policy according to troubleshooting scheme, and on interface, show recovery scheme and processing procedure information, under interactive mode, form with interface provides accident analysis conclusion, dispatcher can carry out fail-over policy by step on display interface, and feeds back in time the executing state of each step.

5. the intelligent distribution network fault handling method containing distributed power source according to claim 1, is characterized in that: described fail-over policy comprises two schemes: a kind of is within the scope of power distribution network contact, to find suitable turning for circuit preferentially to use major network power supply; Another kind is to carry out distributed power source screening, distributed power source boundary demarcation, isolated island sharing of load and distributed power source generating prediction and load prediction to carry out isolated island establishment.

6. the intelligent distribution network fault handling method containing distributed power source according to claim 1, it is characterized in that: in failover procedure, adopt the impact that coordinates to eliminate distributed power source in short circuit current of distributed power source off-grid characteristic and reclosing, comprise following processing procedure:

(1) transformer station's reclosing delay time is increased to 2.5s-3.5s;

(2) on distribution terminal, send over-current signal not do to keep, or shorten the signal retention time to 1s;

(3) increase the overlay analysis function to twice over-current signal.