跨电压等级四回线的横差保护方案

Transverse differential protection for quadruple-circuit lines of different voltage grades

考虑不同电压等级的四回路线路的负序电流特性,提出一种适用于跨电压等级四回线的横差保护方案及其故障选线方案。通过分析故障时的负序电流特征,构建基于负序电流分量的2种横差保护方案,并给出横差保护的整定方法,最后综合横差保护的动作信号提出基于横差保护动作特点的四回线故障选线方案。PSCAD/EMTDC仿真表明,负序电流分量横差保护能准确区分区内故障和区外故障,区内故障时,保护不仅可以正确动作,也可以准确选线,且具有较强的抗过渡电阻能力。

According to the characteristics of negative sequence current in the quadruple-circuit lines with different line volt-age grades,a new transverse differential protection and line selection method are proposed.Firstly,by analyzing the characteristics of negative sequence current for lines on fault,two types of transverse differential protection approach are proposed based on the negative sequence current component.Then,the setting parameters of those two protection methods are calculated respectively.Finally,a line selection method is proposed via a synthesized consideration of action signal from transverse differential protection.A PSCAD/EMTDC simulation is included to verify the proposed method.It is shown that the faults in or out of the protection area can be accurately distinguished.If the fault happens in the line area,the protection can act in time while the faulted line is also selected accurately.Furthermore,this method has a strong capability to resist the transition resistance.