±800kV/500kV交直流混联输电线路反击耐雷水平

Back-flashover resistance level of ±800 kV/500 kV AC-DC hybrid transmission lines

采用PSCAD/EMTDC建立了±800 k V/500 k V交直流混联输电线路反击耐雷水平仿真模型,讨论了杆塔接地电阻、绝缘子片数、雷电流波形、杆塔高度、避雷器变化对耐雷水平的影响,着重从分流系数的角度分析了接地电阻影响反击耐雷水平的原因,比较了±800 k V/500 k V交直流混联输电线路和500 k V同塔双回线路、±800 k V直流线路的反击耐雷水平。理论分析表明:在交直流混联线路中,±800 k V线路的反击耐雷水平是其交流500 k V线路的2倍以上;反击耐雷水平在接地电阻为某一定值时急剧降低;交直流混联线路中,交流线路和直流线路的反击耐雷水平分别大于单独500 k V同塔双回线路、±800 k V直流线路。

A simulation model of back-flashover resistance level is built based on PSCAD / EMTDC for± 800 k V / 500 k V AC-DC hybrid transmission lines and the effect of tower grounding resistance,insulator piece quantity,lightning waveform,tower height and lightning arrester on the back-flashover resistance level is discussed. The effect of grounding resistance on the level is emphatically analyzed from the aspect of shunt coefficient. The back-flashover resistance level of ± 800 k V / 500 k V AC-DC hybrid transmission lines is compared with that of 500 k V dual-loop lines on same tower and that of ±800 k V DC line respectively. The theoretical analysis shows that：as the ± 800 k V / 500 k V AC-DC hybrid transmission lines,the back-flashover resistance level of its ± 800 k V line is above two times higher than that of its AC 500 k V line,while the back-flashover resistance level of its AC and DC line is higher than that of stand-alone ± 800 k V DC line and 500 k V dual-loop lines respectively;the back-flashover resistance level drops abruptly when the grounding resistance reaches a certain value.