750 kV输电线路相差保护中的电容电流补偿问题仿真研究

研究了国内外750 kV线路继电保护的发展状况，根据西北电网750 kV超高压输电线路的具体参数，建立了750 kV超高压线路的EMTP模型，对750 kV超高压线路的特殊问题和在不同系统运行方式下的各种故障情况进行了仿真计算，探讨了采取各种补偿措施后普通相量差动保护、故障分量差动保护和零序差动保护的动作特性及效果，并对750 kV和500 kV线路差动保护的动作特性进行了比较分析，仿真结果表明：750 kV西北超高压长线路保护需采用带电容电流补偿的普通相量差动保护和故障分量差动保护相结合的差动保护，并以零序差动保护作为辅助保护。

Research and Simulation of Capacitance Current Compensating Countermeasure for Phase Differential Protection of 750 kV Transmission Lines

The authors study the development situation of 750KV transmission line relay protection home and abroad.According to the concrete parameters of 750kV transmission lines in Northwest China power grid, the EMTP model of 750kV transmission line is built by which the simulation of special problems of 750kV transmission line and that of various fault conditions under different system operation modes are carried out.The operation characteristics and effects of common phasor differential protection, fault component differential protection and zero-sequence differential protection are discoursed upon while various compensation measures have been adopted, and comparative analysis on operation characteristics of differential protections for 750kV transmission line and 500kV transmission line is conducted.Simulation results show that as for long distance EHV transmission line in Northwest China power grid, the differential protection combining common phasor differential protection with capacitance current compensation with fault component differential protection should applied, and zero-sequence differential protection is used as auxiliary protection.