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.
出处
《中国电力》
CSCD
北大核心
2016年第5期59-62,共4页
Electric Power
关键词
零序方向保护
暂态特性
CVT
互感
zero-sequenced directional protection
transient characteristics
CVT
mutual inductance
