特高压双回路GIL感应电压电流计算分析

Calculation of induced voltage and current of UHV double loop GIL

气体绝缘线路(GIL)回路间电磁感应关系不同于架空导线,线路中存在GIL将会影响感应电压、电流的计算结果,从而影响线路地刀的选型。文中以同塔双回架空线和GIL混合特高压线路为例,研究回路间电磁感应的计算。首先对GIL进行电气参数计算,并理论推导混合线路感应电压、电流计算公式;其次利用EMTP-ATP仿真验证理论分析结果,分别仿真研究了GIL在母线位置、在线路中间以及不含GIL 3种工况下的感应电压、电流变化规律,并分析了GIL在线路中间时感应电流大幅度增加的原因;最后研究了GIL在线路中长度占比的不同对感应电压、电流的影响。研究结果可为含GIL的混合线路地刀选型提供理论计算参考。

The electromagnetic induction relationship among gas insulated line(GIL)circuits is different from overhead conductors.The existence of GIL in the line affects the calculation results of induced voltage and current,thus impacting the selection of line grounding knife.The double-circuit overhead line on the same tower and the GIL hybrid UHV line are taken as examples to study the calculation of electromagnetic induction between loops.Firstly,the electrical parameters of GIL are calculated.The calculation formula of relationship between induced voltage and current of transmission line with GIL is analyzed theoretically.Secondly,the theoretical analysis results are verified by EMTP-ATP simulation,and the induced voltage and current change law of the GIL in the busbar position,in the middle of the line and without GIL are simulated separately,and the reason for the large magnitude of induced current when the GIL is in the middle of the line is analyzed.Finally,the influence of difference length proportion of GIL in line on the induced voltage and current is studied.The research results provide a theoretical calculation reference for the selection of ground switches on mixed lines with GIL.