10kV配电网系统弧光接地过电压研究

比较了中性点直接接地、不接地、经消弧线圈接地等接地方式的安全性和供电特点,从理论上利用EMTP/ATP电磁暂态程序建立仿真模型,以吉林省66 kV某变电站发生的10 kV单相接地故障为例,计算了弧光接地过电压并分析了降低弧光接地过电压的措施,得出中性点经消弧线圈接地,能够降低弧光接地过电压的幅值;接地残流小于10 A时接地电弧易于自熄弧;弧光接地过电压标幺值由中性点不接地时的2.01降至0.97;在脱谐度绝对值相等条件下,消弧线圈工作在过补偿和欠补偿状态下的弧光接地过电压幅值相差不大。

Study on Arc Grounding Overvoltage in 10 kV Power Distribution Grid System

The safety and power supplying characteristics of the grounding methods,including neutral point grounding,no grounding and grounding via arc suppression coils are compared.Simulation model has been established based on EMTP/ATP electromagnetic transient state program.For an example,arc suppression over voltage are calculated and its precautions are analyzed according to a 10kV single phase grounding fault in a 66kV substation.It has been concluded that neutral point grounding via arc suppression could reduce the amplification of grounding over voltage.Self-distinguishing tends to occur when the grounding residual current is less than 10 A.The arc grounding over voltage p.u.dropped from 2.01 when neutral point not grounding to 0.97.When the absolute values of self-tracking compensation are equal,the difference of arc grounding voltage amplifications of the arc suppression coils under over compensation and less compensation state is not large.