基于无死区零序功率方向的纵联零序保护

常规纵联零序保护的功率方向元件有一定零序电压门槛，因而会存在电压死区，若在一侧零序阻抗特别小的长线路中发生高阻接地故障时，有可能使该侧零序电压低于门槛值，导致纵联零序方向保护拒动。针对该问题，在考虑不平衡零序电压的条件下，提出一种通过判断补偿零序电压与保护安装处零序电压大小的方法，可有效判断出正反方向故障。仿真结果表明，本方案简单，易于实现，可提高纵联零序方向保护的可靠性。

Pilot Zero-sequence Protection Based on No-dead-time Zero-Sequence Power Direction

There is a certain zero-sequence voltage theshold for power directional component of conventional pilot zero-sequence protection,and thus there will be voltage dead zone.If high-resistance grounding fault occurs on the long lines whose zero-sequence impedance is very small in one side,it is possible to make the zero-sequence voltage below the threshold,resulting in the malfunction of zero-sequence directional protection.To solve the problem,a method by comparing the zero-sequence compensating voltage and th...