Title: High-voltage AC. controllable parallel-connection reactor control winding zero-sequence protection method
Application Number: 200610145566 Application Date: 2006.11.22
Publication Number: 1979990 Publication Date: 2007.06.13
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H02H3/26;H02H7/00
Applicant(s) Name: Sifang-Jibao Automation Co., Ltd., Beijing Address:
Inventor(s) Name: Su Yi;Tu Liming;Li Shufeng;Liu Jianfei;Qin Yingli
Attorney & Agent: wuhong wei
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.
Time: 5