110kV双回线路管型复合材料杆避雷线架设与接地方案研究

Erection Scheme of Overhead Grounding Wire on Composite Material Pole and Its Grounding for 110k V Double Circuit Overhead Transmission Lines

我国学者尝试在雷电活动强烈、污秽严重地区的110 k V架空线路应用复合材料绝缘杆,以提高相对地空气间隙距离和爬电距离。然而绝缘水平的提高,复合材料杆还是否需要架设避雷线以及避雷线接地引下线,是防雷面临的关键技术问题之一。针对典型110 k V复合材料杆,对比研究未架设避雷线的复合材料杆与架设避雷线的同电压等级、相同导线高度铁塔线路的雷电性能,考虑2种杆塔线路引雷能力、雷电冲击绝缘强度以及建弧率等因素的差异,发现:2种杆塔线路引雷能力间的差异可以忽略;未架设避雷线的复合材料杆雷电冲击绝缘强度是铁塔的3.5倍,建弧率为铁塔的53%,但是反击耐雷水平仅为24.5 k A,雷击跳闸率高达1.13次/(100 km?a),均明显劣于铁塔。据此,推荐110 k V复合材料杆架设避雷线。然后,对比估算避雷线不同接地方案下雷电性能的差异发现:避雷线若不经引下线接地,则复合材料杆雷电性能明显劣于铁塔,但若经引下线逐杆接地,则雷电性能显著优于铁塔。因此,提出避雷线应逐杆接地。综上所述,110 k V复合材料杆线路防雷接地方案应当采用架设避雷线,且通过金属引下线逐杆接地的设计。

It is attempted for Chinese scholars to apply insulation pole composed of composite material in the erection of 110kV overhead transmission lines located at the regions with strong lightning activity and/or serious pollution to enhance the phase-to-ground air gap distance and creepage distance effectively.However,with the enhancement of insulation level whether the overhead ground wire should be erected on the composite material pole as well as its grounding downlead should be equipped are key problems that the lightning protection technology has to be faced with.As to the composite material pole for 110kV transmission lines,the lightning performances of transmission line erected on it without overhead grounding wire and those of 110kV transmission line erected on the steel tower with the same conductor heights are contrasted and researched,and considering the differences in such factors as lightning attracting ability,lightning impulse dielectric strength and probability of sustainedarc between the two kinds of transmission lines it is found that the difference in the lightning attracting ability between the two kinds of transmission lines can be neglected;the lightning impulse dielectric strength of composite material pole without overhead grounding wire is higher than that of steel tower by 3.5 times and the probability of sustained arc of the former is only 53% of the latter,however,the lightning withstand level of the former is only 24.5k A and the lightning outage rate of the former reaches up to 1.13 times/（100km·a）,and the two indices of composite material pole are obviously worse than those of steel tower.For reasons given above,it is recommended to erect overhead ground wire on composite material poles.Besides,through comparing the estimated results of the differences of lightning performances under various grounding schemes it is found that if the overhead ground line erected on the composite material pole is not grounded via the grounding downlead,the lightning performance of composite material pole is evidently worse than that of steel tower,therefore it is proposed that the overhead ground wire erected on the composite material pole should be grounded one after another.In conclusion,during the design of lightning protection and grounding scheme for 110kV transmission line erected on composite material poles the overhead ground wire should be erected and the grounding of the overhead ground wire should be grounded via metal downlead one after another.