Comparative experimental study of DC breakdown strength of Polypropylene film under various layer arrangements

Department of Electric Power Engineering, Faculty of Electrical Engineering and Informatics, Technical University of Košice, Košice, Slovakia

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Published online: 11 June 2026

Abstract

This paper deals with the DC electrical breakdown strength (DC BDS) of polypropylene (PP) film, a material used in high-performance capacitors. The objective of this paper is to compare the DC breakdown strength of PP films of various layer arrangements, dry or oil impregnated. The experimental part focused on a comparative study of the DC BDS across two distinct types of PP film of different space factors. To investigate the impact of the dielectric material’s overall thickness, test samples were created in one-, two-, and three-layer wound scroll configurations. A significant element of the study was the assessment of impregnation effects on the DC BDS across all samples. Acquired experimental data were analysed with various statistical tools, including the Grubbs’ test for outlier detection and the Weibull analysis for determining the probability of failure. The conclusion provides robust information on the DC breakdown strength of different configurations of layered PP films under test.