110-500kV架空输电线路绝缘配合浅析

Analysis on Insulation Coordination of 110-500 kV Overhead Transmission Lines

为提高高压架空输电线路绝缘配合的可靠性,该文分析了110~500 kV输电线路在工频电压、操作过电压、雷电过电压三种工况下的绝缘配合,操作过电压和雷电过电压的绝缘强度取决于绝缘子串的绝缘水平,工频电压绝缘配合必须符合现场污秽度等级下最高工作电压沿绝缘介质表面持续发展的要求。分析和应用实例表明,采用统一爬电比距和最高相电压计算爬电距离更为合理,在轻污区,由外过电压、内过电压决定绝缘水平,随着污秽等级上升,工频电压成为绝缘水平的决定因素。

In order to improve the reliability of insulation coordination of high voltage overhead transmission lines,this paper analyzes the insulation coordination of 110-500 kV transmission lines under three working conditions:power frequency voltage,switching overvoltage and lightning overvoltage.The insulation strength of switching overvoltage and lightning overvoltage depends on the insulation level of insulator strings,and the power frequency voltage insulation coordination must meet the requirement of continuous development of the highest working voltage along the surface of insulation medium under the field gradation for surface pollution.The analysis and application examples show that it is more reasonable to calculate the creepage distance by using the unified specified creepage distance and the highest phase voltage.In lightly polluted areas,the insulation level is determined by external overvoltage and internal overvoltage,and with the rise of pollution level,the power frequency voltage becomes the decisive factor of insulation level.