气体绝缘变电站空载母线残余电荷释放电压响应

Voltage Response of Trapped Charge Release of No-load Bus in Gas Insulated Substation

为研究隔离开关操作过程中残余电荷分布与释放对特快速暂态过电压(VFTO)的影响,基于以电荷密度和电流为变量的传输线方程模型(C-model),应用有限元法(FEM)和时域有限差分法(FDTD)分析了气体绝缘变电站(GIS)内空载母线不均匀残余电荷释放时产生的电压响应。应用ANSYS迭代分析了简单动静触头间电压达到击穿电压时空载母线残余电荷的面电荷密度,并将该面电荷密度转化为线电荷密度。研究结果表明:残余电荷在触头上各处分布极不均匀,空载母线电位和电荷分布随电源侧电位和击穿前动静触头间距离的变化而变化;在最严重情况下,即残余电荷量对应基准电压(205.7kV)产生的量时,由不均匀分布的残余电荷释放产生的空载短线的电压响应最大值的标幺值可达2.9,是电荷均匀分布时的4.3倍。

In order to study the effect of distribution and release of residual charges on very fast transient overvoltage（VFTO） during switching process of disconnectors,on the basis of transmission line equations related to charge density and current along the line（C-model）,we used the finite element method（FEM） and finite difference time domain（FDTD）method to analyze the voltage response at the end of no-load bus with releasing unevenly distributed residual charge.The surface charge density of residual charge was analyzed iteratively by using ANSYS,when the voltage between simple static and dynamic contacts reached the breakdown value.The surface charge density was further transformed into line charge density.The results show that the charge is unevenly distributed on the contact,and the potential and charge of the no-load bus varies with the potential of source and the distance between moving and fixed contacts before breakdown.Meanwhile,with an amount of residual charge caused by rated voltage（205.7 kV）,which is the severest case,the specific value of voltage response generated by unevenly distributed charge releasing can reach 2.9,which is 4.3 times as much as that on the bus with releasing uniform residual discharge.