In this paper

the test and study on breakdown characteristic of the metallized film under superposition of AC and DC electric fields at different temperatures and film thickness conditions are performed.It is shown by the test result that the breakdown strength of the metallized film decreases with the rise of temperature and the increase of film thickness.Therefore

it is suggested this paper adopting arrangement with definite optimization element in the design process of the metallized film capacitor so to enhance heat dissipation.During its operation

a definite cooling method should be adopted to reduce the temperature of metallized film capacitors so to improve the dielectric performance of the capacitor.In case of selecting film thickness of capacitor

it shall be selected in accordance with its voltage level with comprehensive consideration as per actual situation.The study result of this paper can be able to provide a reference for the design of dielectric performance and optimization of operating performance of such capacitor.