弱电源系统的输电线路保护方案的探讨

Discussion of Transmission Line Protection Scheme for Weak Power Source System

输电线路存在弱电源系统,线路发生区内故障,由于弱电源侧系统不能提供足够的短路电流而不能启动保护,导致两侧保护不能快速跳闸甚至拒动。本文分析了弱电源系统输电线路故障特征,提出弱馈输电线路保护配置宜采用纵联方向(距离)、光纤电流差动保护,尤其光纤电流差动保护利用两侧电压信息能彻底解决弱馈线路存在的问题。弱电源侧选相问题,光纤电流差动保护能很好解决,纵联方向(距离)保护需采用弱馈识别的逻辑,在弱电源侧选用突变量电压及稳态量序分量电压选相,是保证重合闸合闸成功的关键。

When the transmission line exists in weak power source system and the internal fault occurs on the line, the protection relays can not operate quickly to isolate the fault line, as the relay fixed at weak power source can not provide enough fault current to startup. This paper analyses the line fault characteristics in weak power source system, and puts forward schemes suitably to adopt pilot directional (distance) relay or optical current differential protection, especially the latter using twain side voltage can solve the weak source problems completely. Phase selection on weak power source side can be solved perfectly by optical current differential relay. It's key to ensure reclosing successfully which pilot protection utilize fault voltage variation and steady sequence voltage to select phase on weak side by making use of weak-feeder logic.