同杆并架双回线保护选相元件研究

RESEARCH ON FAULT PHASE SELECTOR OF PROTECTIVE RELAY FOR DOUBLE CIRCUIT LINES ON THE SAME TOWER

该文对几种常用的故障选相元件在同杆并架双回线故障下的动作行为进行了研究,提出了一种选相新方法。研究表明相电流差突变量、稳态电流序分量等选相元件在发生某些跨线及转换性故障时会误选相。在对跨线及转换性故障特点进行分析的基础上提出了一种新的基于单回线单侧电压电流量的综合选相元件,这种选相元件是在比较故障相电压的基础上判别故障相电流的相位条件来实现的。试验表明这种选相元件与相电流差突变量、稳态序分量选相元件配合可以较好地解决同杆并架双回线故障下特别是跨线及转换性故障下的正确选相问题,保护利用分相式通道在判别两侧选相结果后可实现选相跳闸。

In this paper, the research on some fault phase selectors for double circuit lines on the same tower and a new fault phase selection scheme are presented. The fault phase selectors, including the phase current difference suddenly-change and the sequence current, may misoperate in some cross country faults and conversion faults. Based on the analysis of above faults in double circuit lines, a novel synthesis fault phase selector using voltages and currents in single circuit at single side is proposed, which is based on comparing the difference of fault voltages and judging the phase degree condition of the fault currents. Used this scheme and the phase current difference suddenly-change & the sequence current, the fault phase may be picked up correctly in double circuit lines on the same tower, especially in cross country faults and conversion faults. With multi-phase channels and fault phase selection results at both sides, the protective relay may cut off the selected fault circuit.