The degradation of power capacitors under the influence of harmonics

Power capacitors (PC) may be impaired by the presence of harmonic components. An adequate evaluation of the degradation process imposed by harmonics on a PC should take into account the long-term mechanisms of degradation of PC and the possible additional stresses imposed by the harmonics. This paper presents the degradation mechanisms for all-film PC, with emphasis on the activities of partial discharges (PD). A methodology for the evaluation of the influence of the harmonic in the degradation of PC, based on the applied voltage and its respective waveform, is developed.