接地变中性点经电阻接地在风电场中的应用

Analysis on the Application of Neutral Point of Grounding Transformer Grounded by Resistance in Wind Farm

随着电网的不断改进和陆上风电场的地形条件限制,风电场集电线路电缆逐渐代替架空线路钢芯铝铰线,大大降低了集电线路发生遭受雷击和接地故障的几率.但是,集电电缆线路一旦发生接地故障,电容电流很大,接地电弧不能可靠熄灭,易造成单相接地过电压烧坏设备的事故.因此,三角形接线的主变低压侧配电系统要人为设计制造系统的中性点,接入接地变压器,用来连接适合的接地电阻.当系统发生故障时,这种设计可大大降低接地电容电流,提高接地保护的灵敏度,进一步保障集电线路运行的稳定性、可靠性和安全性.

With the continuous improvement and development of the power grid,the overhead lines are gradually replaced by the power collection cable lines in the wind farm,which greatly reduces the probability of the failure of the power collection lines.However,in case of grounding fault of the collector cable,the capacitance current is very large,and the grounding arc can not be extinguished reliably,which is easy to cause the single-phase grounding overvoltage to burn out the equipment.Therefore,for the distribution system with triangle connection,the neutral point of the system shall be manufactured artificially,and the grounding transformer shall be connected to connect the grounding resistance.When the system fails,the current of the grounding capacitance shall be greatly reduced to further ensure the stability,reliability and safety of the operation of the collection line.