500kV变电站局部接地改造

Improvement of Local Grounding in 500 kV Substation

针对湖南某500 k V变电站接地网部分腐蚀断裂、避雷器接地不合理,导致变电站接地网电位分布不均匀、反击事故、接触电压及跨步电压过高等问题,结合电力系统相关规程及变电站现场实际情况,提出对接地网进行局部接地优化改造措施。优化措施采取重新铺设站内局部接地网以及对避雷器接地进行局部冲击优化,并对新换接地网施加GPF-94高效膨润土降阻防腐剂。采用电磁暂态仿真软件ATP-EMTP进行优化效果仿真分析,得出此方案能有效改善雷电冲击电流作用下接地网地电位的分布、降低接触电压和跨步电压和反击率,提高变电站接地网的安全可靠性。

Aiming at the uneven distribution of substation ground potential, the counterattack accidents, as well as the step and contact voltages much higher etc. problems in Hunan province 500 kV substation, which caused by partial corrosion cracking of grounding grid and lightning arrester grounding unreasonable, combining with the relevant procedures and power system transformer substation site actual situation, the optimization measures of local grounding for grounding grid are proposed. The optimization measures taken repaved station and the local grounding grid, through arrester grounding impact local optimization, and exert GPF-94 high efficient of grounding systems located in bentonite drag-reducing preservatives. The optimization effect simulation analysis has been carried out based on ATP-EMTP, the results show that the measures can effectively improve the ground potential distribution under the action of lightning impulse current, reduce the step and contact voltages, reduce counterattack rate, and improve the safety and reliability of the substation grounding grid.