The validity check of zero-sequence operating direction for transformer directional over-currentprotection is also essential.
另外还需要进行变压器零序方向过电流保护动作方向正确性的检查。
2
Protection for these isolated systems has been a relatively simple task, which is carried out using over currentdirectional relays with selectivity.
采用具有选择性的过电流方向继电器，对这种相互分隔直流系统的保护相对就简单。
3
A directionalprotection based on traveling wave current polarity comparison which is implemented by detecting the polarity of current wavefront of traveling wave is presented.