Research on Electrical Ageing Evaluation Model of Polyimide Film Based on Statistical Analysis

Polyimide (PI) film has some good electrical properties, which is widely used inner insulation of the electrical equipments. The existing lifespan evaluation on PI film is lack of researches on the applicability of the lifespan evaluation models and the validity of data to result in large deviations for the evaluation results. In order to improve the accuracy of the lifespan evaluation model, the consistency of mechanism for electric ageing test was studied in this paper. The PI films breakdown lifespan data with the same ageing mechanism is analyzed by Weibull distribution and lognormal distribution. The influence of two kinds of electrical lifespan models under different probability distribution on the lifespan evaluation for PI films was obtained by inverse power model (IPM) and exponential model (EM) fitting data. The results show that this method verifies the applicability of the evaluation model and the validity of the test data to improve the accuracy of lifetime evaluation for the samples. Moreover, this method can be applied in the lifespan evaluation for the other solid dielectrics.