发电厂500 kV GIS升压站主变压器合闸过电压分析

Analysis on Switching Overvoltage of Main Transformer in 500 kV GIS Booster Station of Power Plant

发电厂GIS升压站具有高度封闭化的特点,在GIS断路器操作过程中产生的暂态过电压过程复杂。以某发电厂500 kV GIS升压站主变压器合闸过程中出现的绕组绝缘损坏事故为分析对象,采用电磁暂态分析软件ATP-EMTP建立发电厂一次设备及变压器绕组分布参数等值电路,对故障变压器合闸过电压及变压器内部电压分布进行了仿真计算。分析结果表明,变压器合闸过程中未出现超过其理论耐受能力的过电压;通过合闸时刻变压器绕组电压分布与绕组损坏情况对比表明,变压器绕组绝缘击穿的原因是其自身绝缘缺陷。

The GIS boost station in power plant is highly enclosed,and the transient overvoltage process is very complicated during the operation of GIS switches.Taking the winding insulation failure occurred in the closing process of main transformer in a 500 kV GIS boost station of a power plant as analysis object,the equivalent circuit of primary equipment and transformer winding distribution parameters is established by using the electromagnetic transient analysis software ATP-EMTP.Simulation calculation is carried out for the closing overvoltage of the transformer and the voltage distribution inside the transformer.The analysis results show that there is no over-voltage exceeding the theoretical tolerance during the transformer closing process,and the comparison between the voltage distribution of the transformer winding and the damage of the transformer winding shows that the fast transient overvoltage is not the cause of the transformer winding insulation breakdown and the real cause is the insulation defect itself.