Fault diagnosis of substation grounding grid based on the signal distance function

Good grounding condition is great important to keep the safety of staff and stable operation of electrical equipments in the substation. Electric power system is an urgent need for practical and effective diagnostic method without excavating the grounding grid and affecting the normal operation of the system, which can look for the location of corrosion and diagnose the degree of corrosion of grounding grid, so as to evaluate safety performance of grounding. This paper adopts the electromagnetic induction principle, pours the excitation current of different frequency sine wave into the grounding through CDEGS analysis software of grounding grid, simulates and analyzes the distribution of magnetic induction intensity in the surface; diagnoses the defects state of grounding grid conductors according to the change of distributional characteristics; calculates the value of the signal distance function for the distribution of magnetic induction intensity when the grounding grid conductors is in the corrosion and breakage; and finds out the specific difference of the each waveform according to the value of mutual distance, to achieve the fault diagnosis of grounding grid.