Research On Treatment Of Capacitor Film Using Plasma Produced By Gas Discharge

High energy density capacitors have dramatic application prospect both in defense and civil field. Organic film capacitors have been widely used in the high energy pulse applications and electrical power systems in virtue of their excellent characteristics such as high Eb, low dissipaton factor. To enhance the electrical strength of the dielectric medium is the most effective way of raise the energy density of the film capacitors. Under high electric field, the ageing of the capacitor film have been accelerated mainly due to the exist of the space charge from the electrodes. Therefore, a possible way of enhancing the film's working electrical strength is to block the electrons from injecting into the insulation mediums from the electrodes.This paper proposed an idea to treat the surface of the organic film using non-thermal equilibrium plasma. The treatment can produce homogeneous and large molecular weight polar groups on the films. These chemical reactions may change the structures of the surface, and bring about a highεr layer, leading to the reduction of initial charge carrier and decrease of electron conductivity in the bulk.The paper firstly describes a set of device for treatment of capacitor film using plasma produced by gas discharge. Three kinds of popular organic film, that are Polypropylene (PP) , Polyphenylene Sulfide (PPS)and Polyester(PET), were treated by O2, N2 and Ar. Some key influencing factors, including composition of plasma, parameters of the power source and structure of the electrodes, were comparatively studied. Changes of the microstructure on materials surface have been detected by use of an infra-red spectrometry and scanning electron microscope. According to the statistical measurements of PP films, the improvement of breakdown voltage after treatment is not obvious. It is shown that the surface has become rougher and the microstructure has been changed. Some sorts of polar radicals have been introduced, but the density is not high, making it difficult to arrest the space charge macroscopically. Due to restricted detecting tool, it is difficult to find macroscopical result. The main effect of our treatment appears to be the surface corrosion. The roughness can make the surface resistance decreased, improve the dipping more effective.