变电站35kV系统小电阻接地方案研究

根据变电站35kV负荷的性质,提出经小电阻接地的方案,并在进行充分分析的基础上,重点介绍了中性点电阻接入系统的方式:接地变直接接于主变△线圈引线,经Z型接地变中性点接小电阻接地;Z型接地变经高压开关接在35kV母线上。还介绍了接地变及电阻柜的选择、保护配置和设计的原则,为今后35kV系统经小电阻接地的改造提供了成功的运行经验。

Study on grounding via small resistance of 35 kV system in substation

According to the characteristics of 35 kV load of substation,a scheme of grounding via small resistance is presented. Analysis focuses on the connection mode of neutral resistance:the Z-type grounding transformer,which is grounded via small resistance at its neutral point,is directly connected to the winding of delta-type main transformer;the Z-type grounding transformer is connected to 35 kV busbar via high-voltage switch. The selection of grounding transformer and resistance cabinet,the protection configuration and the design principle are also introduced,which provide experiences of 35 kV system retrofitting in grounding via small resistance.