500kV GIS变电站快速暂态过电压研究

The Research of Very Fast Transient Overvoltage in 500kV GIS Substation

GIS变电站中开关操作引起的快速暂态过电压易对高压设备特别是变压器产生威胁,针对此问题,采用EMTP/ATP对500 kV变电站进行建模计算,为提高计算精度,隔离开关燃弧采用动态电弧模型,为分析VFTO对变压器匝间绝缘的影响,变压器绕组采用等效电路模型。计算比较了变压器侧开关操作和母线带电时母线侧隔离开关操作产生的VFTO幅值、波形和频谱,并评估VFTO对设备主绝缘的威胁,结果表明母线带电时母线侧开关操作在开关设备上产生的VFTO较为严重;同时计算了变压器绕组内VFTO的分布,结果表明,高频电压主要集中在绕组入口近端线饼和线匝上,1至2匝间电压最大,占入口电压的5.9%。

The very fast transient over voltage caused by switching operation in GIS substation may threats equipments＇ insulation especially transformers, To research this problem, EMTP/ATP is adopted to calculate the overvohage in 500 kV substation, and a dynamic arcing model is used to simulate arc resistance in disconnector to improve the calculation accuracy, to analyze the influence of vFro on interturn insulation by, equivalent circuit model of transformer winding is established. Then amplitude, waveform and frequency spectrum of VFTO by switching operation in transformer side and bus side is calculated and compared, and the threat to equipment＇s major insulation is assessed, results show that VFTO caused by switching operation in bus side when the bus is charged is more serious; at the same time, the distribution of VFI＇O in transformer winding is calculated, results show that high frequency voltage concentrates on the cokes and interturns near the winding entrance, voltage of interturn 1-2 is the largest, which account for 5.9% of the entrance voltage.