上海城市电网110kV中性点接地方式对过电压的影响

Influence of neutral point gounding methods for Shanghai 110 kV grids on over-voltage

电缆、自耦变在上海110 kV城市电网的应用日益广泛,导致单相短路电流水平不断增大,促使人们考虑重新选择110 kV系统的中性点接地方式。介绍了上海市电力公司"上海城市电网主变110 kV侧中性点接地方式研究"课题组的研究成果。仿真结果表明:中性点加接小电阻或小电抗使110 kV单相短路电流限制在25 kA以下是可行的,其所引起的过电压对设备的影响不大。

The increasingly popularized application of cables and autotransformers to Shanghai 110 kV grids has resulted in the increase of single-phase short-circuit current level,which makes people reconsider the neutral point gounding methods for 110 kV grids.The achievements of the project of ＂Research on the neutral point gounding methods for the 110 kV side of main transformers of Shanghai urban grids＂ are recommended.Simulation shows that it is feasible to control the single-phase short-circuit current below 25 kA for 110 kV systems by applying small resistances or reactors for the neutral point,and the over-voltage induced will not exert great impact on the equipment.