基于综合量的相间故障距离保护新方案

为得到更简单的距离保护方案,以对称分量法为基础推导出和、差两分量和综合量,并分析其应用于电力系统相间距离保护的理论依据,比较了测量元件分别加入和、差分量和综合量时,距离保护反映电力系统相间短路故障位置正确性问题。金属性相间故障时,综合量能正确测量保护安装处至故障点间距离,且发生两相接地故障时测量阻抗与过渡电阻无关。用相和、差量实现的测量元件解决了Y,d11变压器d侧两相短路故障时相间测量元件测量阻抗不能正确反映被保护线路与变压器正序阻抗的问题,且原理简单。

New Phase-to-phase Fault Distance Protection Scheme Based on Comprehensive Weight

Based on the symmetrical component method,the sum component,difference compo-nent and comprehensive weight were derived to get a simple distance protection scheme.The the-oretical basis of applying them into the phase distance protection of power system was analyzed, and the correctness of distance protection in reflecting the phase-to-phase short-circuit fault pos-tions was compared by adding each of them into the protection devices.When metallic phase-to-phase fault occurs,the comprehensive weight can correctly measure the distance between the po-sition of installed protection and the fault point,and the measured impedance has no relation to the transition resistance when double phase-to-ground fault happens.If side short-circuit fault oc-curs in the transformers d,the measured impedance can not protect the line and the positive se-quence.The use of measuring devices realized by phase summation and dispersion quantity can solve this problem easily with a simple working principle.