特高压双回路GIL感应电压电流计算分析

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。

Calculation of induced voltage and current of UHV double loop GIL

The electromagnetic induction relationship between GIL circuits is different from overhead conductors. The existence of GIL in the line will affect the calculation results of induced voltage and current, and thus affect the selection of line grounding knife. This paper focuses on the calculation of electromagnetic induction of UHV double circuit overhead lines on the same tower with GIL. Firstly, the electrical parameters of UHV GIL are calculated. The calculation formula of induced voltage and current of transmission line with GIL is analyzed theoretically. Secondly, the EMTP-ATP modeling and simulation are used to verify the theoretical analysis results. The induced voltage and current changes of different position of GIL such as in substation bus position, middle position of line and without GIL are studied respectively. The influence of different length proportion of GIL in line on induced voltage and current is also studied. This paper calculates and analyzes the phenomenon that the induced current of the maintenance line increases greatly when GIL is in the middle of the line. The research results can provide a theoretical reference for the selection of grounding switches for lines with GIL.