As the key components, metallized film capacitors (MFCs) are widely used in power system. When in a harsh environment with high temperature and humidity, oxygen and moisture in atmosphere will permeate into MFCs and initiate electrode corrosion, which contributes to capacitance loss, and thus the reliability is reduced. In this work, a capacitance loss model for atmospheric corrosion is proposed to study the aging pattern of MFCs, and also an accelerated aging test is carried out to investigate the corrosion behavior at various temperature and humidity conditions. The results indicate the corrosion sites tend to distribute around the fibers on polymer films. The capacitance loss rate is reduced over time due to the formation of oxide layers. It is also found temperature has a predominant effect on corrosion process in contrast of humidity.

Metallized film capacitor,Atmospheric corrosion,Capacitance loss,Temperature,Humidity