A significant increase in the efficiency of modern metallized film capacitors has been achieved by the application of special segmented nanometer-thick electrodes. The proper design of the electrode segmentation guarantees the best efficiency of the capacitor's self-healing (SH) ability. Meanwhile, the reported theoretical and experimental results have not led to the commonly accepted model of the SH process, since the experimental SH dissipated energy value is several times higher than the calculated one. In this paper, we show that the difference is caused by the heat outflow into polymer film. Based on this, a mathematical model of the metallized electrode destruction is developed. These insights in turn are leading to a better understanding of the SH development. The adequacy of the model is confirmed by both the experiments and the numerical calculations. A procedure of optimal segmented electrode design is offered.

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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.

Metallized film capacitors widely used in energy applications were studied. The experimental method for investigation of energy and dynamic characteristics of self-healing processes in real metal-film capacitors was developed. The commercial PET and PP MFCs of 0.22 – 1 μF capacitance and 63–250 V voltage were tested. Depending on applied voltage, 3 types of SH processes in MFC were discovered: single, repetitive, and multiple SH. Dependencies of self-healing energy on breakdown voltage were obtained. These dependencies are described by power law with the exponent n = 2.2–2.4 that significantly differs from literature data. The obtained data will be used for degradation and aging laws formulation for capacitors’ energy storage capability improvement.