高海拔地区绝缘子并联间隙雷电冲击试验研究

Research on lightning impulse experiment of insulator strings with parallel gap at high altitude area

针对阿里联网工程中海拔4000 m以上线路的雷电防护需求,设计并试制了高海拔地区用110 kV、220 kV电压等级的绝缘子串并联间隙,每个等级的并联间隙依据基准绝缘子串长度的85%和90%设计有两种不同的结构型式,在西藏国家电网高海拔试验基地对绝缘子串和并联间隙开展了雷电冲击特性试验,测试研究了高海拔110 kV、220 kV瓷绝缘子串以及不同型式并联间隙的雷电冲击50%放电电压、伏秒特性和并联间隙保护有效性。试验结果表明,所有型式的并联间隙均能有效疏导电弧路径保护绝缘子串免遭电弧烧蚀,而考虑到并联间隙伏秒特性曲线较绝缘子串的应降低10%以上,110 kV电压等级并联间隙适合选用85%间隙距离型式,220 kV电压等级并联间隙两种型式则均可满足运行需求。

In response to the lightning protection requirements of transmission lines above the altitude of 4000 m in the Ngari power interconnection project,the parallel gaps of 110 kV and 220 kV insulators are designed and trial-produced.The parallel gaps of each level are designed according to 85%and 90%of the length of reference insulator strings.In order to verify the performance of the parallel gaps in high altitude areas,a lightning impulse characteristic test is carried out at the High Altitude Tibet Test Base of the State Grid.110 kV,220 kV ceramic insulator strings and different types of parallel gaps are tested and studied.The lightning impact 50%discharge voltage,volt-second characteristics and protection effectiveness of parallel gap protection are tested.Experimental results show that all types of parallel gaps can effectively protect the insulator string from arc ablation.The parallel gap volt-second characteristic curve is required to be reduced by more than 10%compared with the insulator string.Therefore,the 85%gap type is suitable for the 110 kV voltage level.Moreover,both two parallel gap types of the 220 kV voltage level can meet the operating requirements.