惠州电网小电流接地系统存在问题及解决对策

在分析各种电网接地方式特点的基础上,指出由于中性点经消弧线圈接地系统发生单相接地故障时故障电流小,信号微弱,使得采用消弧线圈接地与小电阻接地并存模式的惠州电网单相接地故障选线问题未能得到有效解决。为此,提出将消弧线圈接地方式改为小电阻接地方式和提高配电变压器保护配置的解决方案,并给出按限制接地故障短路电流、限制弧光接地过电压、与继电保护配合3种选择小电阻的方法,以及整改现有配电网保护配置的具体措施。

Problems of Small Current Grounding System in Huizhou Power Grid and the Solutions

On the basis of analyzing characteristics of earthing mode of various grids, the paper presents that under circum- stance of single-phase earthing fault the fault current is small, the signal is weak, which makes single-phase earthing fault line selection difficult to solve in Huizhou power grid on which arc suppression coil earthing and small resistance earthing co- exist. Therefore, the paper proposes to replace arc suppression coil earthing with small resistance earthing and improve pro- tection configuration of distribution transformer; besides, it proposes three small resistance selection methods such as restric- tion of short-circuit current in earthing fault, arc grounding overvoltage and relay protection coordination as well as some specific measures for rectify protection configuration of distribution networks.