应对极端雷击情况下的变电站接地网优化设计研究

Optimal Design of Substation Grounding Grid Under Extreme Lightning Strike

现阶段对于中小型变电站接地网的设计、建造缺乏理论指导,很大程度上只能依靠工程技术人员的经验和思维,一旦发生雷击变电站的情况往往导致站内地电位陡升,严重危害二次侧设备安全稳定运行,为了应对极端雷击变电站避雷针情况下引起站内地电位剧升的情况,针对接地网提出了5种优化措施,以站内最大地电位抬升为考核指标,分别对优化措施进行考核,在CDEGS中搭建起接地网及避雷针的试验模型,得到不同优化措施下的地电位抬升分布,试验结果表明提出的5种优化措施均能在不同程度上奏效,其中降低土壤电阻率及扩大接地网面积对于雷击变电站避雷针这种极端雷击情况下降低站内地电位抬升的效果显著,试验结果可以为现有变电站接地网应对极端雷击情况的改造、建设提供工程思路和经验,具有工程应用价值。

Due to lack of theoretical guidance, the design and construction of the grounding grid for small and medium-sized substations can only rely on the experience and thinking of engineering technicians to a large extent. Once lightning strikes the substation, the potential in the substation will rise sharply, which will seriously endanger the safe and stable operation of the secondary side equipment. In order to deal with the sharp rise of potential in the substation caused by extreme lightning strike, five optimization measures are proposed for the grounding grid. Taking the maximum potential rise in the station as the evaluation index, the optimization measures are evaluated respectively. The test models of grounding grid and lightning rod are built in CDEGS, and the distribution of ground potential rise under different optimization measures is obtained. The test results show that the five optimization measures are all effective in different degrees, including reducing soil resistivity. Expanding the area of the grounding grid has a significant effect on reducing the potential rise in the substation when lightning strikes the lightning rod of the substation. The test results can provide engineering ideas and experience for the construction of the substation grounding grid in response to the extreme lightning, and have engineering application value.