Study On Friction And Wear Mechanism Of Transformer Insulation Paper

With the rapid development of economy,transformer has become an integral part of daily life,and the development of power system has become a national key development project.Therefore,the safe operation of transformer has always been the focus of national attention.According to statistics,the proportion of winding faults in transformer accidents is about 80%and winding faults are almost caused by insulation failure.At present,most of the research on insulation paper is devoted to improving its electrical performance or monitoring aging state,but insulation paper damage caused by transformer winding vibration will also lead to insulation failure.Therefore,in this paper,the wear of winding insulation paper under the influence of magnetic fretting is deeply studied,and the wear mechanism of insulation paper is analyzed through friction and wear experiments,and the most vulnerable position of winding insulation paper due to vibration is determined by simulation,the detail contents are as follows.The main causes of transformer vibration are analyzed.The influence of transformer vibration on winding insulation paper is determined.The friction and wear tester UMT-2 were used to test the friction and wear of the insulation paper.The effects of the thickness of insulation paper,before and after oil immersion,friction times and normal load on the wear of insulation paper were analyzed.The friction coefficient and friction morphology of insulation paper were extracted to study the wear mechanism of insulation paper.The results indicate that when the friction times and normal load are constant,the thicker the insulation paper is,the less the damaged layers are,and the friction coefficient decreased as the thickness increased.When the thickness,friction times and normal load of insulation paper are fixed,the number of damaged layers of oil impregnated insulation paper is less than that of non-impregnated insulation paper,and the friction coefficient of oil impregnated insulation paper is obviously less than that of nonimpregnated insulation paper.The main wear mechanism of non-impregnated insulation paper is delamination wear,and the main damage form of oil impregnated insulation paper is stress fracture.When the thickness of insulation paper is fixed,the increase of normal load and friction times will increase the number of damaged layers,and the friction coefficient of insulation paper increases with normal load.The friction and wear experiments between oil impregnated insulation paper and oil impregnated insulation paper were carried out by using the friction and wear tester UMT-2.The effects of the thickness of insulation paper,normal load and friction times on the wear of insulation paper were compared and analyzed.The results indicate that the damaged profile of oil impregnated insulation paper presents irregular rough section.The debris accumulation of thin oil impregnated insulation paper is more obvious than that of thick oil impregnated insulation paper,and the damaged range is larger.Under the same normal load and friction times,the thicker the paper is,the less the damaged layers are.In the initial friction process,the friction coefficient of oil impregnated insulation paper increases with the increase of thickness.Under the same thickness of oil impregnated insulation paper,the greater the friction times and normal load,the more damaged layers of oil impregnated insulation paper,and the friction coefficient decreases with the increase of normal load.The surface damage in oil paper-oil paper friction is fretting wear.The main wear mechanisms are abrasive wear,delamination wear and adhesive wear.In order to determine the most easily damaged part of winding insulation paper,the friction process of winding insulation paper was analyzed by finite element simulation.It turns out that the first wear is at the joint of the insulation paper block and the contact between the board boundary and the insulation paper block.