Impact of Temperature on Internal Resistance of Metallized Film Capacitors

Paper in proceeding, 2022

Metallized polypropylene film (MPPF) capacitors are commonly used in high voltage and pulsed power applications. One of the parameters determining their performance is the internal resistance, which under normal conditions is defined by the dielectric material. At higher operating temperatures, the role of other structural elements on overall performance of the capacitor may become deterministic, but it is usually neglected. In the present work, a model of total internal resistance for MPPF is proposed that allows for investigating the roles of various constituent resistances. In particular, the influence of dielectric material resistance and interlayer air resistance on changes in the overall internal resistance of MPPF capacitor at different temperatures is analyzed. The capacitors (100 nF, 250 Vdc) from three different manufacturers were procured from the market and tested by measuring the steady state leakage current at 60 to 100% of the rated voltage (to determine field-independent conductivity of dielectric material) and temperatures 25⁰C, 50⁰C and 75⁰C.