Aging Life Assessment of Oil-paper Insulation of Traction Transformer Under Shock Load

Traction transformers have been withstood the effects of shock load, which would become more than 2~3 times rated load when the train passes, and it can result in the winding insulation under short-term high temperature frequently. And the average load far less than 50% result in relatively low oil temperature, the very uneven rise of temperature lead to the very uneven distribution of insulation aging. In order to evaluate the aging life of oil-paper insulation of traction transformer under shock load effectively, in this paper, Ekenstam aging kinetic model was optimized considering the effect of shock temperature, shock duration and shock interval on cellulose degradation rate of insulating paper. Firstly, the effects of shock temperature, shock duration and shock interval on the parameters of Ekenstam model are analyzed and determined by handing and testing experimental materials. Then, according to the test data, the Ekenstam optimization model considering shock temperature, shock duration and shock interval is obtained. Finally, the optimized model is verified by experiments. The results show that the optimization model can effectively evaluate the aging life of oil-paper insulation of traction transformer under shock load in the temperature range, which provides a basis and reference for the subsequent related research.