Statistical study on tree inception voltage of silicone rubber and epoxy resin

Weibull distribution has been used widely by many researches around the world especially in the analysis of high voltage experimental data. Unfortunately, most of the experimental data analysis was not following the accurate statistical technique. Thus in this paper, a statistical study on the tree inception voltage of silicone rubber and epoxy resin is presented. The tree inception voltage of silicone rubber and epoxy resin was measured via camera-equipped online monitoring system. The leaf-like specimen was used as test sample. The experiment was performed based on IEC 1072:1991 “Methods of Test for Evaluating the Resistance of Insulating Materials against the Initiation of Electrical Trees”. The obtained results were analysed statistically by using fitting method. Anderson-Darling goodness-of-fit test was performed in order to obtain the best fitting distribution. Comparison exercise was made between the fitted distribution and Weibull distribution. Based on Anderson-Darling tests, the tree inception voltage of silicone rubber and epoxy resin was best fitted with Johnson SB distribution. Based on this fitted distribution, the value of tree inception voltage for silicone rubber and epoxy resin was calculated and equalled to 3.1529 kV and 4.6528 kV respectively. Thus, it was found that, the fitting method by means of Anderson-Darling goodness-of-fit test was successful to recognize the best fitted distribution for the value of tree inception voltage for silicone rubber and epoxy resin.