500 kV自耦变压器中性点加装小电抗的设计及选型方法

摘要

500 kV自耦变压器中性点经小电抗接地是限制电网短路电流的有效手段。利用EMTPE对主变压器中性点接入小电抗后的过电压及绝缘配合进行研究。通过计算正常运行下中性点小电抗的工频及操作过电压水平，以及系统接地故障、合闸及重合闸等操作时小电抗上的操作过电压和暂态电流，确定了主变压器中性点MOA的参数配置，并总结了加装主变压器中性点小电抗的选型方法。%It is an effective means to limit the short-circuit current by grounding the neutral point of 500 kV autotransformers with a low reactance. With the EMTPE software the paper investigates the over-voltage and insulation coordination of the low reactance as it being installed with the transformer neutral point. Calculating the power frequency and operation over-voltage of the low reactance under normal operation status as well as its over-voltage and transient current in the cases of grounding faults, switching on and reclosing, the paper determines the configuration parameters of MOA for the neutral point, and summarizes the model selection method of the low reactance.