防范交流失压引起距离Ⅲ段保护误动的措施探讨  

Discussion on measures to prevent malfunction of distance protection Ⅲ due to AC voltage losing

作　　者：陈水耀[1,2] 黄少锋[1] 裘愉涛[3] 杨松伟[2] 

机构地区：[1]华北电力大学电气与电子工程学院,北京102206 [2]国网浙江省电力公司检修分公司,浙江杭州311232 [3]国网浙江省电力公司,浙江杭州310007

出　　处：《电力系统保护与控制》2016年第10期126-130,共5页Power System Protection and Control

摘　　要：距离III段保护作为本线和相邻线路的后备保护,动作区往往采用阻抗偏移特性。由于保护在启动后退出PT断线判别功能,非故障线路距离III段保护在区外故障伴随交流失压时容易误动,严重时会引发变电站母线全停。为防止距离Ⅲ段保护误动,从电压回路和动作特性两个方面提出防范对策:1)公共电压的直流电源、重动回路及切换回路均按双重化设计,从源头上避免交流失压;2)根据电流值有条件开放阻抗偏移特性,提高距离III段保护的容错能力。Distance protection III is backup protection of own line and adjacent line. Its action zone often has impedance offset characteristics. Because the PT breakage discriminating element will exit once the protection starts, the distance protection III of non-fault line will trip incorrectly when external fault occurs accompanied by AC voltage losing, even leading to all blackout of substation bus in serious case. To prevent malfunction of distance protection III, two measures are put forward based on voltage circuit and action characteristics： 1） DC power supply, reinitiated circuit and switch circuit of public voltage are all dual-designed which can avoid AC voltage losing from the source; 2） the impedance offset characteristics is opened conditionally according to the current value which improve the tolerance ability of distance protection III.

关 键 词：交流失压 距离III段 误动 阻抗偏移 双重化设计 

分 类 号：TM773[电气工程—电力系统及自动化]