小电流接地系统接地检测(选线)的新判据

The New Predications for Criterion of the Non-Effective Earthing System

针对当前在小电流接地系统中 ,尤其是经消弧线圈接地的系统中 ,所装设的接地检测 (选线 )装置正确动作率不高的问题 ,对这些装置的接地检测 (选线 )判据进行分析 ,得出正确动作率不高的原因 ,找到接地检测 (选线 )的新判据 ,制出高精度零序电流互感器和采用新判据的新型接地检测(选线 )装置。通过数百次动模试验 ,证明新判据严谨、准确、简单 ,即使在经消弧线圈接地的系统中 ,装置选线正确动作率也可达到 10 0 %。因此 。

At present,there are many kinds of discrimination equipment for earth fault,which are used in the power system grounded through zero sequence current,especially that with grounding coil,but the function correctness is low.After analysis of the criterions for grounding line,the reason is found.Therefore,the new criterion is proposed,the most accurate sensor TA for zero sequence has been made and the new type equipment has been designed.By a great quantity of test,it is proofed that the new criterion is strict,correct and simple,and the function correctness can reach 100%,even in the power system with zero sequence grounding coil.The new criterion has nice application value.