A Nonlinear Iteration ECT Algorithm for the Reconstruction of Permittivity Graded Insulation

Dielectric with functionally graded material (d-FGM) is a novel insulation with spatially non-uniform permittivity distribution. This kind of insulation structure could relieve field distortion and uniform surface electric distribution, thus improving flashover voltage remarkably. The detection of parametric distribution is essential for the estimation of d-FGMs. Herein, a nonlinear electrical capacitance tomography (ECT) iteration algorithm is proposed to reconstruct the parametric distribution of permittivity graded material ( $\varepsilon$ -FGM). Compared to conventional reconstruction algorithm like Tikhonov, Landweber, the proposed algorithm has better accuracy with respect to a multi-layer permittivity graded structure. Furthermore, the effects of noise level, and the number of layers is systematically investigated. The numerical results indicate that this iteration strategy also possesses good robustness.