Polymer film capacitors are widely used in modern power equipment, because of excellent volumetric characteristics in combination with high-voltage application ability. Using segmented electrodes of nanometer thickness increased the capacitor's performance and reliability because of the self-healing feature. In this paper, we present the results of the experimental investigation and numerical simulation of electrothermal destruction of the metallized film capacitors segmented electrodes during the self-healing process. The destruction processes were investigated for both a single gate and single segment, comprising four parallel gates connected to the segment. The numerical simulation was conducted by means of COMSOL Multiphysics software. The model takes into account the heat flow from metal layer to polymer film since it has significant influence on the destruction process. Based on a good agreement of experimental and numerical results, the simulation model was proposed for the real metallized film capacitor segmented electrodes design. The model allows evaluating the single segment isolating time during self-healing, the energy required for the isolating, effective value of segmented electrodes surface resistance.