接地网电位升对10kV避雷器的反击仿真分析

Backflash Simulation Analysis of Ground Potential Rise on 10 kV Arrester

为解决目前部分接地网设计难度较大的变电站地网接地网电位升(ground potential rise,GPR)过高的问题,首先分析了国内在依据避雷器的工频耐受电压来确定地网GPR限值方面存在的不足。接着通过电磁暂态程序ATPdraw建立了接地网对10kV避雷器的反击模型,在此基础上对地网GPR反击避雷器的放电电流和吸收能量进行了大量的仿真计算。计算结果表明,当10kV系统仅布置1组电站型避雷器YH5WZ-17/45或电机用避雷器YH2.5WD-13.5/31时,避雷器的放电电流分别为61.94A和113.5A,吸收能量分别为3 101.9J和13 947J,均小于允许的通流容量。将不同GPR下避雷器吸收能量与允许的通流容量进行对比,得到了电站型避雷器YH5WZ-17/45和电机用避雷器YH2.5WD-13.5/31的GPR耐受限值分别为11.7kV和10.2kV,可作为合理确定接地网GPR允许值的参考依据。

In order to solve the problem that the ground potential rise（GPR） of some grounding grids with designing difficulties is too high,firstly,we analyzed the deficiency of currently setting GPR limit according to arresters’ power frequency withstand voltage in China.Then,we established a model of a grounding grid’s backflash on a 10 kV arrester by means of the software ATPdraw,by which computation of the arrester’s discharge current and energy when ground potential rise backflashed the 10 kV arrester was simulated.The results indicate that if one set of YH5WZ-17/45 arresters or YH2.5WD-13.5/31 arresters is arranged in a 10 kV power system,the discharge current is 61.94 A and 113.5 A,respectively,and the absorbed energy is 3 101.9 J and 13 947 J,respectively,which are all within the arresters’ flowing energy allowance.By comparing the absorbed energies under different GPRs with the arresters’ allowable flowing energy,the withstand GPR limits of the two arresters,YH5WZ-17/45 and YH2.5WD-13.5/31,are derived as 11.7 kV and 10.2 kV,respectively,which can be a reference for setting reasonable GPR limits in grounding grid designs.