线路纵联零序方向保护误动机理分析及对策研究

针对纵联零序方向保护克服零序电压死区导致过补偿的问题，提出一种改进的零序电压的补偿方法。该方案通过补偿线路全长的三分之一来实现，保证纵联零序方向不会两侧同时出现过补偿误动，同时保证内部故障时，保护具备一定的灵敏度。首先对纵联保护零序方向补偿进行分析，提出造成零序方向补偿误动的新零点。提出一种改进型零序补偿方案，同时以负序方向为辅助判据，改进纵联零序方向保护的性能。仿真试验结果证明了该方案的可行性和正确性。

Mechanism analysis and countermeasure research on the misoperation of the zero sequence directional pilot protection of line

In order to solve the overcompensation problem caused by the zero sequence directional pilot protection which is designed to overcome the zero voltage dead zone, an improved zero sequence voltage compensation scheme is proposed, which is realized by compensating one third of the line length. In this way, the both sides simultaneous misoperation caused by overcompensation is prevented. At the same time, the sensitivity is ensured under the situation of internal fault. First of all, the analysis of compensation of the zero sequence directional protection is carried on, the new zero point is raised, and furthermore an improved zero sequence compensation scheme is put forward, whose auxiliary criterion is negative sequence, leading to an improved function of zero sequence directional pilot protection. The simulation result verifies the feasibility and correctness of the scheme.