Research On Aging Characteristics And Reliability Evaluation Of Oil-Paper Insulation Of Traction Transformer For Emu

The scale of China’s railway,as we know,has made big progress over the past few years.At the same time,the level of research and manufacturing of high-speed railway electric locomotives has increased significantly as well,and world-renowned achievements have been made.As the key equipment of EMU,current extraction,voltage switching and transmission are the traction transformer’s mainly mission.The regular operation of the traction transformer mainly hinges on the insulation capability.Whenever the insulation breaks down,the energy supply will be influenced,and accident might happen.Thus,it will generate a bad influence on electrified railway.Therefore,How to give early warning to the insulation state of traction transformers of EMU and how to evaluate the insulation aging state are the key research issues.At present,there are many types of insulation materials used in the insulation system in EMUs.So the internal insulation combinations are diversiform.Therefore,in the long running process of EMU,different oil paper insulation combination reflects diversiform aging and deterioration rules,which makes reliability assessments difficult.In order to study the degradation law of different insulation systems and grasp their degradation condition in more detail and more comprehensively,So that we can evaluate the degradation state of internal insulation of traction transformer of EMU more comprehensively.Based on the emu traction transformer insulation materials and the actual operation condition,in this paper,Nomex insulating paper and ordinary transformer insulating paper are selected as solid insulating materials,and silicone oil 45#mineral oil is used as liquid insulating materials to form four kinds of oil-paper insulation combinations,and designed the damp and accelerated thermal aging test paper insulation,through testing the oiled paper insulation composite insulating paper tensile strength,microstructure and dissolved gas in transformer oil,insulation aging analysis of the above three parameters changing with the aging time,studied the different ageing properties of the emu traction transformer oilpaper insulation combination.Meanwhile,This article compared and analyzed the changes of the FDS curve of each combination under two states,and explained the causes for the related dielectric phenomena.Based on the modified Havriliak-Negai dielectric relaxation model,the relevant dielectric characteristic parameters of the dielectric spectrum are extracted effectively by using Grey Wolf optimization algorithm,and the variation of the dielectric parameters is analyzed.Finally,the reliability assessment of each oil-paper insulation combination of EMU traction transformers is studied.The above research is of great meaning for effectively supervising the insulation condition and steadily assessment of the traction transformer of the EMU.