TN-S系统接地故障环路阻抗计算和测试问题探讨

Discussion on Calculation and Test of Earth Fault Loop Impedance of TN-S System

针对目前TN-S系统接地故障环路阻抗计算和测试中有几种相似但不完全相同的最大允许电缆长度计算公式,不同公式和不同系数取值会得出不同结果的情况,在分析这些公式中不同参数的合适取值和不同取值引起误差的同时,对接地故障保护校验提出建议。

There are multiple similar but not identical formulas for calculating the maximum allowable cable length in the calculation and test of earth fault loop impedance of TN-S system at present.Different formulas and different coefficient values will lead to different results.While analyzing the appropriate values of different parameters in these formulas and the errors caused by different values,some suggestions are put forward for the verification of earth fault protection.