Grounding grids break diagnosis with consideration of underground pipe

Grounding grid is an essential means for the safety of operators and power apparatus in substation. Many approaches including transient electromagnetic method have been applied to diagnose faults in grounding grids. This paper investigated break point diagnosis of grounding grids with consideration of underground pipe. Based on the equivalent resistivity distribution characteristics, the grounding fault can be accurately located in the grounding grids. The influence of underground pipe on the distribution of equivalent resistivity is analyzed. Factors including underground pipe made of different materials and buried in different depth are discussed in detail. The results show that the underground pipe puts a great impact on fault diagnosis of grounding grids.