35kV城网中性点经消弧线圈并联电阻接地方式下弧光接地过电压研究

选取过补偿脱谐度相对较小的消弧线圈以补偿电容电流,减小弧道残流、降低电弧重燃次数、提高故障自恢复概率;选取阻值相对较低的并联电阻以快速泄放对地电容的零序电荷,提高健全相、故障相及中性点的过电压衰减速度,减小熄弧后中性点恢复电压的上升速度和幅值,以有效抑制弧光接地引起的暂态过电压。ATP仿真结果表明,中性点经消弧线圈并联电阻接地方式是适用于电缆与架空导线混合的35kV城市配电系统较为理想的接地方式。

Analysis and Simulation on Intermittent Arc Grounding Overvoltage for Neutral Grounding via Arc-suppression Coil with Shunt Resistance in 35kV Urban Distribution Systems

Some arc -suppression coil which has a relatively small overcompensation tuning -off degree is mainly used to compensate the capacitive current of line to ground , reduce the arc residual current and reigni-tion times, and then to increase the self -restoration probability after single phase intermittent arc grounding fault occurs.At the same time , a relatively small shunt resistance is mainly used to release the charge of line-to-ground capacitance quickly , improve the decay rate of fault and non -fault phase , s and neutral point , s overvoltage , reduce the rising speed of neutral point , s recovery voltage and its amplitude after the intermittent arc put out , so that the transient overvoltage can be restrained effectively.Results of ATP simulation have demonstrated the mode of neutral grounding via arc -suppression coil with shunt resistance is optimum choice which is applicable to 35 kV urban distribution networks mixed by overhead lines and cables.