Adaptive weak-infeed pilot protection method of transmission line

Abstract

The invention relates to an adaptive weak feed (weak infeed) tripping method of relaying protection in the power system field, which is characterized in that when the circuit is weak feed circuit, only one of the two sides of the traditional pilot distance protection and the pilot direction protection needs to be determined as the weak feed side in advance, and the two ends can not be confirmed as the weak feed side in advance, especially for blocking type pilot protection. On the basis of the current pilot protection, the invention puts forward adaptive weak feed logic and solves the problemof insufficient sensitivity after repeated start of conversion of strongness and weakness at the two sides of the circuit in coordination with other criteria. Meanwhile, in the blocking type signals,the coded incompletely enabling signals are added, thus improving the safety of the adaptive weak feed logic.

Description

technical field [0001] The present invention relates to the field of electric power systems, and more specifically relates to power system relay protection under the condition that both sides of the weak feeder line are preset in advance, which can reliably trip for various internal faults on the line, and can reliably trip for external faults or disturbances. methods that can be reliably distinguished. Background technique [0002] With the expansion of the scale of my country's power grid and the construction of various large-scale power projects, 500kV lines have been widely used. Lines with higher voltage levels have also been put into operation. The power network has gradually become the main network with 500kV transmission lines. With the de-loop operation of 500kV and 220kV electromagnetic ring network, the operation mode of some 220kV substations has undergone great changes. The 220kV line often changes between the tie line and the terminal line. When the line is t...

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Problems solved by technology

[0003] In order to solve the above-mentioned problems existing in the prior art, it is required to pre-set both sides of the line protection as the weak feeder side. It can automatically judge which side is the strong current side and which side is the weak feeder side. The line protection with the characteristics of the strong current side can trip quickly, and the weak feeder side has a certain delay exit. For the weak feeder line In the case of high-impedance faults, the traditional longitudinal protection does not have a good solution. This invention solves the problem that both sides of the weak-feeder line protection cannot be preset as the weak-feeder side at the same time, and can also solve it very well. High-impedance faults on weak feeders

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