L型GIS管道对电磁波传播的影响及等效电路建模  

Influence of L-Shape Part of GIS Enclosure on Electromagnetic Propagation Characteristics and Equivalent Circuit Model

作　　者：曹书云[1] 焦重庆[1] 

机构地区：[1]华北电力大学新能源电力系统国家重点实验室,北京102206

出　　处：《电气技术》2016年第11期6-12,共7页Electrical Engineering

基　　金：国家重点基础研究发展计划项目(973计划)(2011CB209405);国家电网公司科技项目“特高压GIS变电站VFTO关键技术应用研究”资助

摘　　要：在GIS管道中传播的电磁波，在诸如拐弯、盆式绝缘子及套管等结构改变的位置，其电磁场分布会产生局部的畸变。这种畸变通常以集总电路元件的形式补偿到描述电磁波的传输线模型中。本文针对管道L型拐弯讨论了由电感和电容组成的兀型和T型两种等效补偿电路。基于电磁场仿真得到的L型管道的二端口网络参数，运用传输线理论导出了补偿电感和补偿电容的计算公式。结合某特高压GIS管道尺寸参数，计算得出兀型补偿时补偿电容大约在15-40pF，补偿电感大约在0．08～0．23μH，且随频率变化；T型补偿时，电容值大约在15-32pF，电感值大约在0．1～0．2μH。比较了考虑和不考虑补偿电路两种情况下传输特性的差异，结果表明，两种情况下终端负载上的时域电压波形的差异与负载阻抗大小有关，总体来说终端开路和短路时差别大，匹配时差异小。Field distribution of electromagnetic wave propagating in a gas insulated switchgear （GIS） can be distorted locally at the discontinuous/abrupt positions like elbows, spacers and bushings. The effect of such distortion is usually regarded as a lumped circuit element inserted into the transmission line model, For L-type elbow of GIS pipe, both n-type and T-type equivalent circuits consisting of compensation capacitance and compensation inductance are investigated in this paper. Based on the two-port network parameter obtained by electromagnetic simulation of the L-shaped pipe, the formulae of both the compensation capacitance and inductance are derived by using transmission line theory. For a 1100kV GIS dimensions, the capacitance is about 15--32pF and the inductance is about 0.1-0.2μH when the T-type circuit adopted, and the capacitance is about 15-40pF and the inductance is about 0.08--0.23μH when the n-type circuit adopted. Both the capacitance and the inductance are changing with the frequency. A circuit including a terminal load on one end of the L-shape pipe and a pulse voltage source on the other end is established to compare the difference between the two cases： with and without the equivalent circuit inserted. It is shown that, the equivalent circuit has obvious effect on the load voltage waveform when the load matches badly with the pipe, but has few influence when the two match with each other well.

关 键 词：GIS 全波仿真 传输线方法 L型 补偿电容 补偿电感 

分 类 号：TM595[电气工程—电器]