Research On Safety Assessment And Renovation Of Earthing Network For Taiping Wan Hydroelectric Power Station

Based on analyses of grounding grid to large hydropower station in worldwide, a new safety criteria of grounding grid is proposed. Comprehensive safety assessment was performed by the assessments and tests of the TaiPingWan power station, then improvement on the grounding grid is implemented.Firstly, the importance of grounding device of hydropower station and the problem to be solved were described, and the common problems existing in grounding grid was analyzed. Simultaneously, methods of the reformation and basic principles of grounding grid are presented.Combining with related large grounding technology and concept in domestic and overseas, safety criteria are suggested according to the parameters of related grounding devices. The criteria involve in uniform potential distribution of electric area, lower grounding resistance, good electrical continuity of grounding lead to all equipment.With analyzing the original design and test of the grounding grid in TaiPingWan power station, grounding resistance and allowed cross-section of grounding lead are recalculated based on regional variation of capacity in short-circuit.By comprehensively testing and analyzing the grounding resistances, potential distribution, grounding conduction, contacting and step voltage, safety in the grounding grid of TaiPingWan power station is reassessed after reforming and retesting.