超高压交流输电线路融冰避雷线绝缘架设对杆塔接地安全的影响

Effect of Ice-melting Ground Wire Insulation Erection of EHV AC Transmission Lines on Grounding Safety of Tower

融冰避雷线绝缘架设方式会对短路电流的分配路径造成影响,进而影响到杆塔接地安全性能。为确保杆塔接地安全,建立了全线绝缘避雷线输电线路短路模型,探讨了避雷线绝缘间隙击穿与短路电流的关系,分析了融冰绝缘避雷线杆塔入地电流,研究了架设绝缘避雷线后对杆塔接地安全的影响。结果表明,架设绝缘避雷线后杆塔入地电流主要由绝缘间隙击穿情况决定;绝缘避雷线间隙发生临界击穿时,将会产生很大的杆塔入地电流,杆塔接地安全受到严重威胁。避雷线直接接地时,杆塔接地装置的安全性能基本满足规程要求;而架设绝缘避雷线后,杆塔接地装置的安全性不能满足规程要求。因此架设绝缘避雷线将严重影响到杆塔的接地安全。

Ice-melting ground wire insulation erection affects the short-circuited shunt distribution and the tower groun- ding safety performance. In order to ensure the grounding safety of tower, we established the short-circuit simulation model of insulated ground wire, and discussed the relationship between insulated gap breakdowns of ground wire and short-circuit current. Then we analyzed the tower grounding current of ice-melting insulated ground wire and the effects of the grounding safety of tower after erecting insulated ground wire. The results show that tower grounding current is mainly decided by insulated gap breakdowns after erecting insulated ground wire. When critical breakdown occurs in the gap of insulated ground wire, there will be large tower grounding current, which seriously threatens the grounding safety of tower. When ground wire is directly grounded, the safety performance of tower grounding devices can meet the re- quirements of regulations on the whole; while after erecting insulated ground wire, the safety performance of tower grounding devices can not meet the requirements of regulations. Therefore, the erection of insulated ground wire can se- riously affect the grounding safety of tower.