CVT暂态特性对工频变化量距离保护的影响

Influence of transient process of CVT on incremental power frequency distance relay

结合EMTDC仿真试验分析得知,CVT暂态过程可能引起工频变化量距离保护超越,且超越现象与短路电压角度和系统线路阻抗比(SIR)值密切相关。在此基础上提出防止超越的措施———故障后提高暂态动作门槛。其具体做法是在推导出实时计算SIR值的基础上,根据SIR值自适应地提高动作门槛。EMTDC仿真试验结合保护仿真程序验证了此方案的有效性。

Under analysis of the EMTDC experimental result, the conclusion is drawn that CVT transient process will make the incremental power frequency distance relay overreach which has close relation to the fault inception angle and SIR（ system impedance ratio） value. Based on above research, a new method enhancing the operating threshold after fault is proposed, which prevents the relay from oven＇caeh. Alter deducing the SIR value through the proposed way, the threshold is enhanced by the SIR adaptively. It is verified by EMTDC program and relay simulation program.