互感引起的零序方向保护误动分析与对策  

Analysis and Countermeasures on a Malfunction of Zero-Sequence Directional Protection Due to Mutual Inductance

作　　者：陈水耀[1,2] 黄少锋[1] 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

出　　处：《中国电力》2016年第5期59-62,共4页Electric Power

摘　　要：粜220kV线路高频零序方向保护在区外故障时误动，保护动作前的电压波形存在明显畸变。通过对电瓜波形进行谐波分析，发现电容式电压互感器（CVT）暂态特性持续时间比较短，一般在5～10ms．而零厅办向保护动作m口在20ms以后，从而排除了CVT暂态特性不良引起零序方向保护误动的可能性。同时小槲线路心侧岑序电压、零序电流及零序阻抗，计算出线路上存在感应电压．从而确认相邻线路互感是导致零序方向保护误判的原因，并有针对性地提出负序电流开放零序方向保护的改进措施。A high frequency zero-sequence directional protection of a 220 kV line took false action with obvious distortion on voltage waveform. Through harmonic analysis of voltage waveform, it is found that CVT transient characteristics lasted shortly around 5 -10 ms, while zero-sequence directional protection acted 20 ms later. The possibility of malfunction caused by transient characteristics of CVT is excluded. Based on zero-sequence voltage, current and sequence on both sides of protection, the induced voltage is calculated. It is inferred that mutual inductance is the cause of malfunction of zero-sequence directional protection. A new zero-sequence directional protection scheme with negative sequence current opening identification is proposed.

关 键 词：零序方向保护 暂态特性 CVT 互感 

分 类 号：TM773[电气工程—电力系统及自动化]