500 kV输电线路绝缘架空地线并联间隙放电原因分析及防范措施

Discharging Analysis and Preventive Measures for Parallel Gap on Overhead Insulating Ground Wire of 500 kV Transmission Line

对蒙东地区500 kV输电线路绝缘架空地线并联间隙放电原因进行了分析,因在设计阶段理论计算得出耐张段小于1 km的线路感应电压最大值为388 V,未在该耐张段绝缘地线设计单点接地,而是全绝缘。但现场实际电压值远超过25 cm并联间隙所能承受的击穿电压值,造成了不间断放电。暴露出线路设计只考虑了单一线路理论计算,没有考虑同廊道多回线路复杂的电磁场环境对绝缘地线感应电压的影响等问题。为确保架空绝缘地线安全运行,提出对500 kV绝缘架空地线采取防范措施:开展同廊道、复杂运行环境绝缘架空电线不同接地形式下感应电压理论计算,以满足运行要求;开展并联间隙距离、绝缘子零值检测,红外测温,及时消除缺陷,防止绝缘地线间隙放电造成地线脱落等问题。

In order to improve the safety operation capability of 500 kV insulated overhead ground wire,the reasons for insulated overhead ground wire parallel gap discharge were analyzed in the eastern area of Inner Mongolia.Through theoretical calculation,maximum line induced voltage of strain section less than 1 km is 388 V.In this area,insulated ground wire strain did not select single point grounding installation,but adopted full insulation.However,the actual value was far more than puncture voltage value that 25 cm parallel gaps could bear,resulting in continuous discharge.In order to ensure the safe operation of 500 kV overhead insulated ground wire,several precautions should be taken:in order to meet the requirements of operation,induced voltage of insulated overhead ground wire under different connecting grounding condition like in same corridor and other complex operating environment should be calculated;in order to eliminate defects in time and prevent ground wire shedding and other serious consequences caused by insulated overhead ground wire gap discharge,parallel gap distance,zero-value detection of insulator,infrared temperature measurement should be carried out.