南方电网直流输电系统接地极线路不平衡保护动作后果探讨

Disscusion on operation results of electrode current unbalanced protection used in HVDC transmission system in CSG

接地极线路不平衡保护用于检测接地极线路故障,首先简介了天广、高肇和兴安等南方电网直流输电系统中接地极线路不平衡保护的动作原理和动作后果,根据直流线路故障的特征,建议将单极方式下接地极线路不平衡保护的动作后果由启动闭锁改进为启动故障重启动功能、将天广直流双极方式下接地极线路不平衡保护的动作后果由告警改进为启动双极功率平衡功能,并结合RTDS仿真指出改进过程中应注意接地极线路和高压直流线路相继故障带来的系统稳定问题,同时也给出了相应的改进建议。

Electrode current unbalanced protection is used to detect the electrode line fault, in this paper, the electrode current unbalanced protection used in Tian-Guang,Gao-Zhao,Xing-An HVDC transmission system are introduced first, and then based on the characteristics of DC line fault, the improving suggestions of ameliorating the operation results of electrode current unbalanced protection in monopolar ground return operation and in bipolar ground return operation of Tian-Guang HVDC transmission system are discussed. At last, combined with the simulation on RTDS, the problems of power system stability after amelioration are analyzed.