500kV架空地线不同接地方式下地线感应电量影响因素研究

Study on Influential Factors of Induced Electric Quantity of 500 kV Overhead Shielding Wires at Different Grounding Methods

目前国内500 k V及以上交流超、特高压输电线路大多采用一根钢绞线(GJ地线)和一根光纤复合地线(OPGW)的架设方式。多采用GJ地线分段绝缘、一点接地,OPGW逐塔接地的方式。实际运行经验表明,GJ地线分段绝缘、一点接地不仅电能损耗小,而且并不降低地线的保护性。而OPGW逐塔接地的接地方式在保证通信连续的同时带来地线环流大、电能损耗较大等问题。因此,需要对地线不同接地方式下的感应电量的影响因素进行深入研究。本文以浙江一条运行中500 k V交流输电线路为研究对象,运用电磁暂态计算程序EMTP,对该500 k V架空地线不同接地方式下感应电压、感应环流、能量损耗的影响因素进行了研究,研究成果为地线接地方式的改进和选取提供了参考。

Nowadays, the grounding wires usually use one GJ ground wire by segmented insulation with one-point grounding, and one OPGW ground wire by grounding at each tower for 500 kV and above voltage level in China. Previous practical experiences show that segmented insulation with one- point grounding of GJ ground wire can not only reduce the power loss but also keep the protective character of ground wire. However, OPGW ground wire with grounding at each tower can keep the communication continuous but have the problem of large power loss at the same time. According to this reason, the deeper study of influences of different grounding methods towards induced voltage and current is taken into account. The model of one actual 500 kV transmission line of Jinghua, Zhejiang province is set up by EMTP, to study the influence factors of induced voltage, induced current and power loss at different grounding methods. This study will provide a reference to choose or improve the method of grounding.