Analysis of Internal Electric Field and Optimization of Insulation Structure in Metallized Film Capacitors

As the applied voltage increases, partial discharge has become one of the most important factors affecting the service life of metallized film capacitors. Therefore, the insulating structure of the capacitor needs to be optimized to increase the insulating strength. In this paper, a metallized film capacitor is studied by simulation. Its simulation results show that the maximum electric field strength occur at the edges (inside) of the metallization, the thickness of the metallization and the smoothness of the metallization edges also have a great influence on the maximum electric field strength, and the calculation results of the model established after reducing film number and film width in the correct way are valid. Therefore, a targeted increase in the thickness of the dielectric at the metallization edges is an effective way to reduce the occurrence of partial discharge as well as enhance the reliability of capacitors. In addition, proper metallization thickness and metallization edge treatment can also improve the dielectric strength of the capacitor to some extent.