High-voltage AC. controllable parallel-connection reactor control winding zero-sequence protection method

Abstract

The method includes steps: protector of reactor obtains instantaneous values of current and voltage by sampling waveforms of threephase current transformer (TA) at secondary side of high voltage, AC controllable type shunt reactor; dedicated external zero sequence current (ZSC) transformer, initial end of threephase potential transformer (TV); using Fourier algorithm determines complex form of each electric quantity; when external ZSC of winding at secondary side is larger than fixed value, the first time limit acts on bypass breaker on joined secondary side through T1 time delayed exit; the second time limit acts on tripping breaker on primary side through T2 time delayed exit; calculating self generated ZSC and self generated zero sequence voltage at initial end, and when ZSC is larger than a fixed value, then warning signal is sent after 5s time delay ; and when locking conditions are not satisfied, the first time limit acts on bypass breaker through T3 time delayed exit etc.

Description

technical field [0001] The present invention relates to the field of power systems, and more particularly to a method for relay protection. Background technique [0002] First, the related art of the present invention is briefly described based on the following references. [0003] 1. Chen Weixian, Chen He. Controllable adjustment of shunt reactor [J]. High Voltage Technology, 2006, 26(5). [0004] 2. Li Dayi, Chen Qiaofu, etc. New principle of adjustable reactor based on flux control [J]. Chinese Journal of Electrical Engineering, 2003, 23(2). [0005] 3. Tian Kexing, Li Qingfu. Magnetic field and parameter calculation of transformer-type controllable reactor [J]. Journal of Xi'an Jiaotong University, 2005, 39(6). [0006] High-voltage shunt reactors are an important part of ultra-high voltage and ultra-high voltage power grids. The installation of a high-voltage shunt reactor can compensate the capacitive power of the line, and can limit the operating overvoltage, the c...

AI Technical Summary

Problems solved by technology

The high-voltage AC controllable shunt reactor can operate normally when the secondary winding is short-circuited. In most cases, the short-circuit current after the secondary fault is even smaller than the rated current. If the protection scheme is improper, the high-voltage AC controllable shunt reactor protection The sensitivity of the

The protection method for the primary side fault of the high-voltage AC controllable shunt reactor is similar to that of the fixed high-voltage shunt reactor. and back-up protection are not protected

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