Abstract：In the grounding grid, the magnitude difference between the conductor and the soil resistivity is huge, which leads to the difficulty of the grounding grid electrical impedance tomography. In order to expand the convergence range and improve the ill-health of the inverse problem of grounding grid electrical impedance tomography, a grounding grid electrical impedance tomography based on Homotopy -Tikhonov algorithm (HT-GN) was proposed. Firstly, the forward and inverse problem simulation models were established on the basis of theoretical analysis. Secondly, based on the optimal initial iteration value and the optimal regularization parameters, the reconstruction images of grounding grid simulation by HT-GN algorithm and Tikhonov algorithm were compared. Meanwhile, the reconstruction images with different initial iteration value, different regularization parameters and corrosion degree under light corrosion, heavy corrosion and fracture were quantitatively analyzed for HT-GN algorithm proposed in this paper. Finally, the light corrosion state of grounding grid was simulated and the experiment of electrical impedance tomography of grounding grid was carried out. The results show that the corrosion location of ground grid reconstruction image based on HT-GN algorithm is clearer, and the relative error of voltage after convergence is significantly less than that of Tikhonov algorithm, which effectively improves the ill-health of the inverse problem of grounding grid electrical impedance tomography.
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2022, Vol. 37 
