Inverse features extraction for substation grounding grid: derivative and ICA combinatorial approach

摘要

Optimising the orientation of the unknown grounding grid is effective to measure its accurate configuration. On the other hand, burial depth and conductors' current are essential for the status diagnosis of grounding grid. This study employs the derivative method to determine the above-grounding grid characteristics without excavation. Surface magnetic flux density after the current injection process is subjected to derivative on the circle. The orientation of the grounding grid is accurately measured from the location of gradient peaks. Moreover, the grounding grid depth and conductors current are calculated from peaks width and peak value. The problem of substation intense electromagnetic environment that readily distorts the results of the proposed method is also addressed. Blind source separation famous technique, the fast independent component analysis (FastICA), is utilised to separate the original signal from the mixed signal. Furthermore, the authors also probe the influence of circle radius for the alarming case of a diagonal conductor. Mathematical reasoning, simulation, and experimental results illustrate that the proposed method is feasible to find the inverse features of grounding grid. Furthermore, the signal recovered through FastICA delivers results with high accuracy.