Partial Discharge Phenomena in Power Capacitor Unit Insulation Under Harmonic Resonance Effects

摘要

The capacitor in the electrical system for power factor correction is always damaged when under voltage and current waveforms are distorted. There was a test found that the electrical insulation was damaged and destroyed. In order to learn this damage mechanism it requires a non-destructive inspection method. The partial discharge (PD) testing is a method that can detect deterioration and a defect in the electrical insulating material that is not visible. The purpose of this paper is to investigate the impact of harmonic resonance on power capacitor unit insulation. High voltage capacitor units consist of parallel and series connected elements. The rating of element of capacitor units applied in the power system is 6.67 kVAR/Phase, 400 V. Series resonance can lead to high voltage distortion levels at a low voltage side of transformer resulting in high harmonic current in the element of capacitors. The inspection and element of capacitor unit test are used to obtain power system resonance, a standard operating procedure, testing and measurement between phase to ground using the partial discharge model MPD 600 OMICRON, dielectric losses and capacitance model CPC 100 OMICRON. Finally, the scanning electron microscope (SEM) is used. The comparison of results between new element of capacitor and element under harmonic resonance are performed. The results convey that breakdown in insulating of capacitors under harmonic resonance can be used for considering capacitor voltage rating. The failure of insulation an increase in obtained and emphasized by photograph from SEM.