交流侧故障与换相失败时序问题的分析

摘要

计算交流侧故障与换相失败之间的时间间隔是研究换相失败对交流继电保护影响的基础.该文基于数学形态梯度提取逆变侧直流电流在换相失败期间的局部特征,进而利用不同的局部特征给出了一种统一的计算交流故障与换相失败时序的方法.并利用新的计算原则提出了一种防止由于暂态功率倒向而导致非故障线路纵联方向保护误动的措施.基于PSCAD/EMTDC搭建了仿真模型,仿真实验结果验证了分析结论的正确性.%The calculation of time interval between AC fault and commutation failure is a basis for studying the effect of commutation failure on the AC relay protection.After the extractions of local features of DC current during commutation failure in the inverter side,by using the morphological gradient,a unified calculation method of the time sequence between AC fault and commutation failure is proposed based on different local features.In addition,a countermeasure is put forward to prevent the mal-operation of differential directional protection on un-faulted line caused by transient power converse.A model is built based on EMTDC/PSCAD,and the simulation results show the validity of the calculation method.