三峡—上海±500kV同塔双回直流输电用线路避雷器的雷电防护效果分析

Analysis of Lighting Protection with Line Surge Arrester for the Three Gorges-Shanghai ±500 kV Double-circuit DC Transmission Line on the Same Tower

为研究线路避雷器对±500kV三峡—上海双回直流输电线路的雷电防护效果,对该线路典型杆塔雷击闪络率进行了仿真计算,拟定了线路避雷器的加装方案,分析了加装避雷器后线路的耐雷水平、线路避雷器的最大吸收能量和放电电流。结果表明,16号单回路G1-39型杆塔正极性线路、1383～2123号双回路SGV2AP-45型杆塔上层正极性线路、1725和1737号SGV2AP-45型杆塔上层正、负极性线路雷击总闪络率均>0.14次/(100km.a),建议在上述杆塔上安装线路避雷器。加装线路避雷器后,上述杆塔耐雷水平均得到明显提高,反击耐雷水平>400kA,绕击耐雷水平大于最大绕击电流,且线路避雷器能够满足耐受最大吸收能量1 200kJ和放电电流58kA的技术要求。因此线路避雷器能够可靠保护直流输电线路不发生雷击闪络。

In order to investigate the lightning protection effect of line surge arresters on ±500 kV the Three Gorges-Shanghai double-circuit DC transmission line,the flashover rates of typical towers on the line were calculated.Based on the calculation results,a selective installation model of line surge arresters was recommended.Then the lighting withstand level of the line with surge arresters installed and the lightning discharge energy and discharge current of the surge arresters were also analyzed.The results show that the flashover rates exceed 0.14 times/（100 km·a） in several places,including the positive polar conductor of No.16 G1-39 single-circuit tower,the upper conductor of SGV2AP-45 double-circuit towers from No.1383 to No.2123,and the upper both polar conductors of No.1725 and No.1737 SGV2AP-45 towers,which are recommended to be installed with line surge arresters.After line surge arresters being installed,the lightning withstand levels of the towers mentioned above significantly increase,meanwhile,the their back flashover and shielding failure currents exceed 400 kA and the maximum shielding failure current,respectively,and the line surge arresters can withstand the max energy stresses of 1 200 kJ and the discharge current of 58 kA.Therefore,it is believed that line surge arresters can reliably protect DC transmission lines from lightning flashover.