Research on self-healing characteristics of metallized film capacitor via acoustic and electric combined detection

Abstract

Metallized film capacitor is widely used in pulse power generators and HVDC power transmission system. The high reliability of capacitor is mainly beneficial from the self-healing process. With the increase of its operation time and discharge time, frequent self-healing leads to loss of capacitance. Therefore, it is important to develop an effective detection method to monitor the self-healing characteristics of MFC. In this paper, a self-healing detection method based on acoustic and electric combination is proposed for MFC with high sheet resistance and the self-healing ultrasonic signal is analyzed. The influence of pulsed discharge times on the characteristic of self-healing is studied through online self-healing detection method. The results show that peak frequency of ultrasonic signal is between 50 kHz and 60 kHz. As the number of pulsed discharge time increases, low voltage self-healing discharges become more frequent and the self-healing frequency has same increasing trend with capacitance loss. When the capacitor is near the end of its life, the self-healing frequency increases sharply and the probability of high-energy self-healing point increases significantly. It's indicated that this detection method has a good application prospect for the monitor of aging state of the capacitor through the change of the self-healing characteristic.

Keywords

Identifiers

DOI

10.1049/icp.2022.0093

Journal

IET Conference Proceedings

Year

2021