A Novel Method for Fault Diagnosis of Grounding Grids

Faults of grounding grids are threat to the safety of power system and cause significant economic loss every year in China. Accurate detection of the faults will alleviate these detrimental effects. This paper presents a novel approach using the transient electromagnetic method for fault diagnosis of grounding grids. The induced magnetic intensity is collected by receiver coils in the form of electromotive force. After inversion calculation, the contour map of equivalent resistivity of underground covered by grids is obtained. The faults due to corrosion or break can be accurately located from the distribution characteristics of equivalent resistivity maps. The influence of the fault of different degrees, material of grounding conductor, and soil resistivity on distribution of induced magnetic intensity to fault diagnosis will be analyzed in detail. The effect of the underground pipeline on fault diagnosis of grounding grids is also investigated. Simulation was performed, and a field experiment was conducted to verify the effectiveness of the proposed method.