Research on Corrosion Diagnosis Methods for Substation Grounding Grids

Grounding grid is the key facility of substation, which is used to ensure the safety of equipment and personnel. Corrosion in soil will increase its resistance and lead to the failure of protection function, so corrosion detection is very important. The existing methods (such as sampling excavation and resistance tester) are inefficient and vulnerable to interference. In this paper, a non-contact magnetic field detection method is proposed: injecting specific frequency current into the grounding grid, using wavelet transform to reconstruct the magnetic field signal, and using Particle Swarm Optimization-Support Vector Machine (PSO-SVM) algorithm to diagnose the corrosion degree. Experiments show that this method is more accurate than the traditional SVM algorithm.