GIS隔离开关带分合闸电阻抑制VFTO的研究

Suppression of VFTO by Disconnector with Opening and Closing Resistor in GIS

针对超高压GIS中开关操作或发生接地故障时产生特快速暂态过电压(VFTO)从而影响GIS及其连接设备和二次控制设备的问题,根据800 kV GIS结构特别是母线较长(采用分布参数模拟,并考虑频率特性)的特点,利用EMTP程序对28种接线方式进行数值仿真计算。结果表明:隔离开关装和不装分合闸电阻(500Ω)时VFTO最大幅值分别为1.2932、.976 p.u.;该电阻>200Ω时可抑制VFTO,使其幅值<1.7 p.u.。故800 kV GIS中VFTO幅值对设备绝缘的影响很小,这对于GIS及其连接设备和二次控制设备的绝缘设计非常重要。

During switching operation or earth faults in SF6 gas insulated switchgear （GIS）, Very Fast Transient Over-voltage （VFTO） occurs and will stress adjacent equipment or secondary equipment in GIS. With the increasing of GIS voltage level, the effect of VFTO should be taken more consideration. According to the characteristics of 800 kV GIS structure, especially when busbar is relative long （use distribution data simulation with taking into account the frequency characteristic）, this paper had made data analysis to 28 deferent connection modes using EMTP program. The calculation effect shows that when open/close resistance on the disconnector is installed or not, the Max. amplitude of VFTO is 1. 293 p. u. and 2. 976 p. u. respectively. Data show that since the open/close resistance of disconnector has limited effect on VFTO, the amplitude of the VFTO is not high in GIS. When the open/close resistance is larger than 200 Ω, the amplitude of VFTO can be restrained under 1.7 p. u.. The amplitude of VFTO has little effect on equipment insulation. This is very important for the insulation design of the adjacent equipment and secondary equipment of 800 kV GIS.