农网35kV不接地系统投空载线路零序电压偏高研究

Research of high zero-sequence voltage when switch unloaded line in 35 kV ungrounded rural power grid

由中性点偏移引起的零序电压偏高在国内农网35kV系统中屡见不鲜。以上饶110kV煌固变电站1号主变压器35kV侧投入空载线路后零序电压偏高为例,结合现场实测数据及ATPdraw仿真研究,得出农网35kV输电线路由于不换相施工及线路首、尾端在各别相装设CVT及耦合电容器造成空载线路本身不平衡引起35kV侧中性点零序电压偏高的结论。

It is very normal in 35 kV ungrounded rural power grid because of the neutral excursion. The paper takes 35 kV medium voltage of 1st power transformer of Shangrao 110 kV Huanggu substation switching unloaded line as example, with site measurement data and simulation by ATPdarw, conclusions are obtained.The high zero-sequence voltage is caused by the unbalance of the 35 kV transmission lines which are non-phase converting or installed CVT and coupling capacitor in some phases.