Failure analysis of dielectric of low voltage power capacitors dueto related harmonic resonance effects

摘要

This paper presents an investigation on the failure of low voltagepower capacitors used in the textile industry located in Thailand. Thecauses of the failure as well as the failure mechanisms of thedielectric used as the insulation of such capacitors are analyzed. It isfound that the harmonic resonance can increase the current flowingthrough the capacitors. This results in extra heat, generated inside thedielectric, which exceeds the level under normal operation. Such heatresults in an increase of the partial discharge inside the capacitors.This can eventually lead to the reduction of the lifetime of thecapacitors