某水电站220kV出线场接地装置改造方案的优化设计

Optimal Design of the Retrofit Scheme for the 220kV Outgoing Line Yard Grounding Device of a Hydroelectric Power Station

针对某220kV出线场接地电阻超标情况进行接地装置改造。经计算和分析,共设计了2个外引地网,并分别以镀锌扁钢和铜作为接地极材料进行方案设计。在满足接地电阻、跨步电压、接触电压等国家规程要求的基础上,采用年最小成本费用的方法对两种设计方案进行经济性、可靠性综合比较,选取最优方案。最后采用国际著名的接地分析软件包CDEGS进行计算和校验。该设计提高了水电站出线场接地网改造的性价比和实用性,保证了水电站的安全可靠运行。

In view of the situation that the grounding resistance of a 220kV outgoing line yard exceeds the standards,its grounding device is planned to be reconstructed.After the calculation and analysis of the total design,two external grounding grids are added.The copper and profiled steel are adopted as earth electrodes for the retrofit scheme.Based on meeting the grounding resistance,step voltage and the contact voltage required by national regulations,the minimum annual cost method is adopted and a comprehensive comparison of economic and reliability about the design schemes is performed,then the optimal scheme is selected.Finally,the grounding analysis software CDEGS is used for calculation and verification.This design has improved the performance with high value and practicability and guarantees the safe and stable operation of the hydropower station by the reconstruction of grounding gird.