Lifetime improvement of metallized film capacitors by inner pressure strengthening

This paper concentrates on the inner pressure in the cylindrical metallized polypropylene film capacitor (MPPFC) winding. Firstly, the influences of inner pressure on self-healing and lifetime are investigated. Lifetime can be extended by inner pressure strengthening. Secondly, an inner pressure calculation formula is presented. Finally, the experimental results show that lifetime can be extended by 30% with rational heat treatment and by 38% when the number of wrapped films increases from 20 to 100.