To make fault diagnosis of grounding grids with touchable nodes deviation

the testability of diagnosis directly on the exact grounding grid and on the mirror grounding grid are evaluated by using the theory of hierarchical simplification.A Tabu search based fault approach is put forward to reduce the influence of touchable nodes deviation.Four modes of diagnosis are suggested.An experimental grounding grid with sixty branches is used as an example to illustrate the proposed approach.The results show that the diagnosis directly on the exact grounding grid may obtain a higher clear branch ratio but its amount of test work is very large and that the proposed correction approach is feasible.It also shows that the hybrid method to combine the diagnosis on the exact grounding grid with the correction approach on the mirror grid may further improve the clear branch ratio.