750kV架空地线接地方式及损耗研究

Grounding Modes and Electric Loss of 750 kV Overhead Ground Wire

随着电力需求的增长,电压等级升高,输送容量增大,地线感应环流损耗比例虽然不大,但总量却越来越大,造成运行费用的增加。笔者对多种750 kV架空地线接地方式下地线的感应电压、电流以及损耗进行了计算研究,并对系统产生过电压时地线的运行状况以及地线接地方式对系统过电压的影响进行了分析计算。结果表明:光纤复合地线(OPGW)采取分段绝缘一点接地时,地线电能损耗最小,电气性能最好;不建议OPGW采用全线绝缘或者全线绝缘首末两端接地这两种接地方式;地线的接地方式对线路过电压也有影响,其中采用分段绝缘一点接地方式时,线路过电压较高。

With increasing requirement for electricity, the voltage level and transmission capacity of power transmission lines get larger, which results in more and more electric loss due to inductive current in ground wire and operation cost. In this paper, the amplitudes of inductive voltage and current, the electric loss of overhead ground wire, and the amplitude of overvoltage on transmission line are calculated for different grounding modes. The results show that the amplitudes of inductive voltage and current as well as the electric loss of overhead ground wire get the minimums when 0PGW takes segment insulation with one point earthing, while the zero- sequence impedance and the amplitude of overvohage become higher in this grounding mode. Both grounding modes of overall insulation and overall insulation with two ends earthing for 0PGW are not recommended.