浅析输电线路降低雷害跳闸率的措施

Analysis of Measures for Reducing Tripping Rate of Lightning Stroke on Transmission Line

输电线路塔头绝缘配合设计通常按能耐受系统最大工作电压及操作过电压和以工频泄漏比距选定,以雷电冲放特性校验其耐雷水平,从而基本固定了塔头间距(即绝缘子片数),使线路沿绝缘子串闪络跳闸与由塔头空气间隙击穿放电的跳闸比为10∶1～12∶1,造成输电线路的故障率占全部输变电设备故障的80%左右,同时也钳制了目前环境污染严重情况下配置外绝缘增加结构高度的可能。文章提出外绝缘配置按空气间隙击穿电压与绝缘子串闪络电压0.7左右配合比设计塔头绝缘配合,以V串替代I串方式,形成紧凑化线路,既节约了线路走廊资源,又增加了绝缘子串沿面闪络电压值,可大幅度降低线路雷害沿绝缘子串闪络跳闸的次数。使外绝缘污秽等级提高到3.5cm/kV以上,基本免除了绝缘子串的清扫工作,大大降低了运行维护成本,运行检修单位实现了"减人增效"的目标。

The design of insulation co-ordination of tower top on transmission line was usually determined by maximum working voltage and switching overvoltage as well as power-frequency leakage rate. The spacing of tower top,the number of insulator,was basically fixed according to checking its lightning impulse withstand level by lightning surge characteristic,which made tripping rate 10： 1 ～ 12： 1 caused by flashover of insulator string and air gap breakdown discharge of tower top,and made the fault rate of transmission line taken 80% of electrical equipment fault around,at the same time,which also limited to increase structural altitude of external insulation disposition under the present condition of serious polluted environment. The paper put forward that the insulation co-ordination of tower top was designed according to adaptability ratio 0.7 （breakdown voltage of air gap/flashover voltage of insulator string）,and I string was replaced by V string to form the compact line,which economized line corridor resource and increased the value of creeping flashover voltage of insulator string,and reduced the number of line tripping. The pollution grade of external insulation can be improved to 3.5 cm/kV more,and sweep work of insulator string can be basically avoided,the cost of operation and maintenance can be reduced,the goal of ＂to reduce labour power and increase efficiency＂ can be realized.