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Electrically induced heat dissipation in metallized film capacitors

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journal contribution
posted on 02.09.2009 by Michael G. Kong, Yuen-Pen Lee
Elevated temperature is a key aging factor for metallized polymer film capacitors with the capacitor life expectancy halved with every 8°C of temperature rise. For film capacitors in service, both application of a time-varying external voltage and the extinction of internal breakdown events can deposit significant heat onto the capacitor structure leading to an undesirable temperature rise. Often such heat generation is localized spatially and the resulting temperature gradient enhances the probability of subsequent breakdowns. To facilitate a thorough and generic understanding, a thermal model of metallized film capacitors is developed to simulate the dynamics of heat generation and transfer under the switching impact of an external voltage. Thermal processes in solids (polymer layers, electrode coating, and zinc-spray segment) are modeled with conduction mechanism, whereas convection mechanism is considered for silicone oil and air. Heat generation is induced either by ohmic losses of the externally applied electric field, or by internal breakdown events within the metallized film capacitor structure. This allows a seamless interface between the heat transfer model and the equivalent circuit based field calculation model. Based this electrothermal model, numerical examples are used to study temperature distribution within film capacitors and then to examine the likelihood of localized temperature hot-spots that may lead to spatially preferential breakdowns.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Citation

KONG, M.G. and LEE, Y.P., 2004. Electrically induced heat dissipation in metallized film capacitors. IEEE Transactions on Dielectrics and Electrical Insulation, 11(6), pp. 1007-1013.

Publisher

© IEEE

Version

VoR (Version of Record)

Publication date

2004

Notes

This article was published in the journal IEEE Transactions on Dielectrics and Electrical Insulation [© IEEE] and is also available at: http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=94 Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

ISSN

1070-9878

Language

en

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