Research On Prediction Method Of Residual Life Of Transformer Oil-paper Insulation Based On Wiener Stochastic Model

The quality of transformer oil-paper insulation directly determines the operating condition and service life of transformer.At present,a part of transformer oil-paper insulation in our country keeps good condition,while the other part has experienced the problem of insulation deterioration,which is in urgent need of maintenance or even replacement.Therefore,it is of great practical significance to research the assessment method of aging status of transformer oil-paper insulation and calculate the remaining life,and rationally plan maintenance time and replacement.In this dissertation,the aging test of oil-paper insulation is carried out,the dielectric loss factor curve of the insulating pressboard XY model and its corresponding degree of polymerization are periodically tested,and the relationship between the integral quantity of dielectric loss factor and degree of polymerization is established.In terms of the actual operation conditions of transformer,this dissertation has built a multi-factor combined aging test platform,and has conducted oil-paper insulation aging test under the conditions of electro-thermal,electro-thermal-vibration conditions,and periodically tests the dielectric loss factor of the insulating pressboard XY model.The effects of electrical,thermal and vibration aging factors on insulation aging are compared and analyzed.Using the relationship between the integral quantity of dielectric loss factor and degree of polymerization obtained above,the value of degree of polymerization corresponding to oil-paper insulation dielectric loss integral under the condition of electric-thermal-vibration is obtained,so that the degradation data of degree of polymerization of insulating pressboard are obtained.In this dissertation,the Wiener stochastic model for deterioration of oilpaper insulation is deduced theoretically,and the parameters in the model has effectively estimated by combining Bayesian updating and EM algorithm,also the prediction accuracy of the algorithm with and without parameter updating are compared.By substituting the degradation data of the insulating pressboard polymerization degree into the algorithm,the predicted value of the residual life of oil-paper insulation and its probability density function can be obtained.Finally,testing the value of degree of polymerization of insulating pressboard at the end of the predicted life has verified the effectiveness of the remaining life prediction algorithm of oil-paper insulation in this thesis.