一起光伏电站35 kV接地变保护跳闸事件原因分析

Analysis on a Protection Trip of 35 kV Earthed Transformer in Photovoltaic Power Station

基于某光伏电站35 kV母线接地导致接地变保护跳闸事件监控信息,通过对其母线电压故障与接地变电流录波图深入分析,判断此次故障为母线单相短时接地现象,凝露闪络和污闪是其主要原因。提出的整改措施包括加装热缩母排保护套管或使用防污绝缘涂料,利用夜间光伏低发期对35 kV高压室定期清扫且门窗尽量保持常闭,采用碘钨灯交替加热各柜内母线及绝缘设备等。实践证明,这些方法可有效防止类似故障再次发生,为光伏行业类似故障处理提供技术参考。

Based on the trip event monitoring information of earthed transformer protection caused by 35 kV bus grounding in a photovoltaic power station,the voltage fault of its bus and the oscillogram of earthed transformer current were analyzed in depth.It was judged that the fault is the single-phase short-time grounding phenomenon of the bus,and the main reasons are condensation flashover and pollution flashover.The proposed rectification measures include installing heat shrinkable busbar protection sleeve or using antifouling insulation coating,regularly cleaning the 35 kV high-voltage room and keeping the doors and windows normally closed as much as possible during the low occurrence period of photovoltaic at night,using iodine tungsten lamp to alternately heat the busbar and insulation equipment in each cabinet.Practice shows that the method can effectively prevent similar faults from happening again,and provide technical reference for similar fault treatment in photovoltaic industry.