Break point diagnosis of grounding grids using transient electromagnetic apparent resistivity imaging

Summary form only given. Faults in the grounding grid are hidden danger to the safety of power system and cause significant economic loss every year. This paper presents a new means to locate faults in grounding grids using the transient electromagnetic imaging method. The method compares the distribution characteristics of the equivalent resistivity of underground covered by grids for no fault case and those with break points. We describe why and how the proposed method can be used for break point diagnosis of grounding grids. Simulation was performed using Ansoft FEM package, and a field experiment was conducted to verify the effectiveness of the proposed method. This study provides a practical means for break point diagnosis with no requirement of power shut down or soil excavation. Moreover, the proposed method does not require the design drawings of grounding grids.