一起 500 kV 架空线路地线金具发热分析与研究

Analysis and Research on Heating of Fittings of Ground Wire of 500 kV Overhead Transmission Line

摘要:

近年来，时有地线挂点金具发热、烧融导致地线断线进而危害线路稳定运行的事故发生。针对四川500 kV架空输电线路地线金具发热问题，通过理论分析与仿真研究发热原因，提出预防措施以保障线路安全。首先，通过EMTP仿真建模，获得了线路稳定运行状态下地线的感应电压与电流随负荷的变化规律；随后，搭建三维有限元仿真模型，计算了接触电阻、感应电流、风速等参数对金具发热的影响规律；最后，结合仿真结果分析发现其异常发热的主要原因为耐张段上出现两个及以上接地点后构成异常感应回路，使接触电阻处持续流过较大电流，导致金具异常发热。针对这一类型问题提出了可行的解决方案及预防控制措施，为架空输电线路的安全运行提供保障。

Abstract:

Heating and melting incidents of ground wire fitting are a frequent occurrance in recent years, leading to wire breaks and endangering line stability. Aiming at the heating issue of a 500 kV overhead transmission line in Sichuan, through theoretical analysis and simulation, the preventive measures are proposed for line safety. Firstly,through EMTP simulation modeling, the law of induced voltage and current changeing with load is obtained. And then, a 3D finite element model is esatablished to calculate the impacts of contact resistance, induced current and wind speed on fitting heating. Finally, the analysis reveals abnormal heating due to an abnormal induced circuit formed by multiple grounding points on the tension section, causing large currents and heating. It offers the solutions and preventive measures for such typical heating issues, and will ensure the safe operation of overhead transmission lines.