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通过对线路发生单纯性故障与跨线故障情况下的正、负序故障分量阻抗关系和正、负序故障分量电流幅值关系的分析,提出了一种判别电力系统发生跨线故障的判别元件。单纯性故障时,正负序阻抗角相等、正负序阻抗幅值相等、正序故障分量电流幅值不小于负序电流幅值;而当发生跨线故障时,以上关系不再成立,由此便可以得到系统发生跨线故障的判据。该判别元件原理简单,动作灵敏度高,EMTP仿真和现场录波数据验证了该判别原理的准确性。
Based on the analysis of the relationship between the positive and negative sequence fault component impedance and the current amplitude of the positive and negative sequence fault components in the cases of simple line fault and cross-line fault condition, a discriminating element for discriminating the cross-line fault in power system is proposed. For simple faults, the positive and negative sequence impedance angles are equal, the positive and negative sequence impedance magnitudes are equal, the positive sequence fault component current amplitude is not less than the magnitude of the negative sequence current amplitude, and the above relationship no longer holds when the over-line fault occurs This can get the system criterion of cross-line failure. The discriminating element has the advantages of simple principle and high movement sensitivity. The EMTP simulation and live recording data verify the accuracy of the discriminating principle.