CN-122026287-A - Power distribution network protection system and power distribution network protection method

CN122026287ACN 122026287 ACN122026287 ACN 122026287ACN-122026287-A

Abstract

The application discloses a power distribution network protection system and a power distribution network protection method, and belongs to the technical field of power grids, wherein the power distribution network protection system comprises a plurality of first switches, a plurality of power distribution terminals, a second switch and a new energy protection device, under the condition that the power distribution network fails, the first power distribution terminals are determined according to the multistage differential protection strategy, and the first power distribution terminals realize forward locking according to the first switches corresponding to the multistage differential protection strategy and the on-site feeder automation strategy constraint; the new energy protection device constrains the second switch to realize anti-islanding protection according to the multi-level differential protection strategy and the new energy protection strategy, and the anti-islanding protection is configured at the new energy grid-connected point and matched with the multi-level differential protection, so that the problem that after the fault point trips, short-circuit current generated by the new energy reversely flows to the fault point, thereby causing the aggravation of the fault degree and even endangering the personal safety of operation, maintenance and repair staff is prevented.

Inventors

ZHOU WEI
XU JUN
SUN ZENGXIAN

Assignees

北京和信瑞通电力技术股份有限公司

Dates

Publication Date: 20260512
Application Date: 20250930

Claims (10)

1. A power distribution network protection system applied to a power distribution network accessing new energy, the power distribution network comprising a plurality of first segmentation points and new energy grid-connected points, the power distribution network comprising: The first switches are in one-to-one correspondence with the first segmentation points, and each first switch is arranged at the corresponding first segmentation point; The power distribution terminals are in one-to-one correspondence with the first switches and are used for controlling the corresponding first switches; the power distribution terminals are used for determining a first power distribution terminal according to the multistage level difference protection strategy under the condition that the power distribution network fails and enabling the first power distribution terminal to realize forward locking according to a first switch corresponding to the multistage level difference protection strategy and the local feeder automation strategy constraint; The second switch is arranged at a new energy grid-connected point of the power distribution network; The new energy protection device is arranged at a new energy grid-connected point of the power distribution network and used for controlling the second switch, the new energy protection device is configured with a new energy protection strategy and the multistage level difference protection strategy, and the new energy protection device is used for restraining the second switch to realize anti-islanding protection according to the multistage level difference protection strategy and the new energy protection strategy under the condition that the power distribution network breaks down.
2. The protection system of a power distribution network according to claim 1, wherein the plurality of power distribution terminals are further configured to determine a second power distribution terminal according to the multi-level differential protection policy in the event of a failure of the power distribution network, and enable the second power distribution terminal to implement reverse blocking according to the multi-level differential protection policy and a first switch corresponding to an in-situ feeder automation policy constraint, where the second power distribution terminal is a power distribution terminal nearest to a failure point of the power distribution network.
3. The protection system of a power distribution network according to claim 1 or 2, wherein the plurality of first switches comprises a trunk line head switch disposed at a trunk line head of the power distribution network, a first trunk line segment switch disposed at a first trunk line segment of the power distribution network, a large branch head switch disposed at a large branch head of the power distribution network, and a user demarcation section switch disposed at a user demarcation section of the power distribution network; The plurality of power distribution terminals comprise a main line first section power distribution terminal arranged at a main line first section of the power distribution network, a first main line segmented power distribution terminal arranged at a first main line segment of the power distribution network, a large branch first section power distribution terminal arranged at a large branch first section of the power distribution network and a user demarcation section power distribution terminal arranged at a user demarcation section of the power distribution network; The multi-level difference protection strategy comprises a five-level difference protection strategy, wherein the five-level difference protection strategy comprises a first level difference time, a second level difference time, a third level difference time, a fourth level difference time and a fifth level difference time; The outlet switch of the power distribution network is configured with the first level difference time, the first trunk section power distribution terminal is configured with the second level difference time, the first trunk section power distribution terminal is configured with the third level difference time, the large branch first section power distribution terminal is configured with the fourth level difference time, and the user demarcation section power distribution terminal is configured with the fifth level difference time.
4. The power distribution network protection system according to claim 3, wherein the new energy protection device is an anti-islanding protection device, the anti-islanding protection device is configured with the fifth level difference time, and the new energy protection strategy comprises that the anti-islanding protection device controls the second switch to be tripped when the power distribution network fails.
5. A power distribution network protection system according to claim 3, wherein the time values of the first level difference time, the second level difference time, the third level difference time, the fourth level difference time, and the fifth level difference time decrease in order.
6. The protection system of a power distribution network according to claim 5, wherein the first power distribution terminal controls the corresponding first switch to trip according to the corresponding step time in the five-step protection strategy when the power distribution network fails, and then controls the corresponding first switch to switch on according to the on-site feeder automation strategy and then to switch off to realize forward locking.
7. The protection system of a power distribution network according to claim 6, wherein at least one power distribution terminal located downstream of a fault point where the power distribution network fails determines the second power distribution terminal according to a received incoming call duration and the five-level differential protection policy, so that the second power distribution terminal performs reverse blocking according to a first switch corresponding to the five-level differential protection policy and an on-site feeder automation policy constraint, and the incoming call duration is a current duration generated by the second power distribution terminal after detecting that the first power distribution terminal is re-blocked after switching on.
8. The power distribution network protection system of claim 1, wherein the first switch and the second switch are both magnetically controlled switches.
9. The protection system of power distribution network according to claim 7, wherein the five-level differential protection strategy comprises a plurality of differential time intervals, wherein at least one power distribution terminal located downstream of a fault point where the power distribution network fails determines a target differential time interval in which the incoming call duration is located according to the incoming call duration, and determines the second power distribution terminal according to the target differential time interval.
10. A method of protecting a power distribution network using the power distribution protection system of any of claims 1 to 9, the method comprising: Judging whether the power distribution network has faults or not; If the power distribution network fails, a first power distribution terminal is determined according to the multistage differential protection strategy, the first power distribution terminal is enabled to realize forward locking according to the multistage differential protection strategy and a first switch corresponding to the on-site feeder automation strategy constraint, wherein the first power distribution terminal is the power distribution terminal closest to the failure point of the power distribution network, and the second switch is constrained according to the multistage differential protection strategy and the new energy protection strategy to realize anti-islanding protection.

Description

Power distribution network protection system and power distribution network protection method Technical Field The application relates to the technical field of power grids, in particular to a power distribution network protection system and a power distribution network protection method. Background With the continuous development of social economy and scientific technology, particularly the maturation of communication technology, feeder automation modes are proposed. The feeder automation mode mainly utilizes automation and network communication of feeder terminal units to achieve the purpose of quickly searching fault positions. The method has the advantages that the state of the feeder sectionalizer, the state of the tie switch, the feeder current, the feeder voltage and other data are monitored in real time under the normal state, the remote or local switching-on and switching-off operation of the line switch can be realized, fault records are obtained during faults, the fault sections of the feeder can be automatically distinguished and isolated, the power supply can be quickly recovered to the non-fault areas, and the fault power failure time is reduced. The existing on-site feeder automation technology plays a key role in guaranteeing the power supply continuity of the existing power distribution network. However, the existing on-site feeder automation mode mainly adopts a voltage-losing and switching-off power-on strategy, and the fault section isolation and the non-fault section power restoration are realized by means of the switching-on time sequence cooperation of a switch. This in-situ feeder automation mode has the following disadvantages: 1. The number of switch actions is large, and the switch needs to perform multiple actions to realize isolation of a fault area and power restoration of a non-fault area due to an operation mechanism of an in-situ mode, so that the abrasion and replacement frequency of the switch are increased, and the maintenance cost is increased. 2. The power restoration of the in-situ FA (Feeder Automation) mode is carried out after the isolation of all the sections and the branch switches in the section is finished, so that the power restoration processing time is prolonged, and the continuity and the reliability of power supply are affected. 3. And after the new energy is connected to the power distribution network, the sensitivity and the selectivity of line protection are reduced, so that the risks of misoperation and operation rejection are increased. Disclosure of Invention The application provides a power distribution network protection system and a power distribution network protection method, which are used for at least solving one of the technical problems. In a first aspect, the present application provides a power distribution network protection system, applied to a power distribution network accessing new energy, where the power distribution network includes a plurality of first segment points and new energy grid connection points, including: The first switches are in one-to-one correspondence with the first segmentation points, and each first switch is arranged at the corresponding first segmentation point; The power distribution terminals are in one-to-one correspondence with the first switches and are used for controlling the corresponding first switches; the power distribution terminals are used for determining a first power distribution terminal according to the multistage level difference protection strategy under the condition that the power distribution network fails and enabling the first power distribution terminal to realize forward locking according to a first switch corresponding to the multistage level difference protection strategy and the local feeder automation strategy constraint; The second switch is arranged at a new energy grid-connected point of the power distribution network; The new energy protection device is arranged at a new energy grid-connected point of the power distribution network and used for controlling the second switch, the new energy protection device is configured with a new energy protection strategy and the multistage level difference protection strategy, and the new energy protection device is used for restraining the second switch to realize anti-islanding protection according to the multistage level difference protection strategy and the new energy protection strategy under the condition that the power distribution network breaks down. Optionally, the multiple power distribution terminals are further used for determining a second power distribution terminal according to the multistage level difference protection strategy under the condition that the power distribution network fails, and enabling the second power distribution terminal to realize reverse locking according to the multistage level difference protection strategy and a first switch corresponding to the constraint of the local feeder automation strategy, whe