Research On Wear Behaviors Of Transmission Lines Power Fittings Under Strong Wind Environment

With the(+800 kv)Hamilan-Zhengzhou UHVDC project put into operation,Xinjiang power grid has entered the era of UHV.Xinjiang is a major energy province in China,which not only bears the responsibility of "power transmission from Xinjiang",but also the responsibility of cross-border energy interconnection.However,due to the special natural environment in Xinjiang,the wear and tear phenomenon of conventional design of fittings has appeared soon,and the overall safe operation of Xinjiang power grid is not guaranteed.In this paper,the wear behavior of UHV transmission line fittings in strong wind environment is studied.The influence of strong wind on the wear failure behavior of fittings is obtained through the wear experiment.The wear process of fittings is studied by ANSYS Workbench method.The failure prediction of fittings under a certain model is completed,and the fatigue life prediction values of electric fittings under different wind speeds are obtained.The wear experiment of U-shaped ring of power fittings is designed according to the actual windy environment.The wear experiment of U-shaped ring of power fittings is carried out under different loading and wear times.The morphology,structure and structure of U-shaped ring were analyzed by means of scanning electron microscopy,metallographic microscope and hardness.Through the wear test of Ushaped ring,it can be found that the failure load of U-shaped ring decreases gradually with the increase of different applied loads and wear times;the contact area of Ushaped ring has obvious delamination phenomenon through scanning electron microscopy analysis;the plastic deformation of the contact area of U-shaped ring can be observed from the pictures of metallographic microstructure,and the grain edge along the contact area of U-shaped ring.The hardness of the contact area decreases obviously as the deformation direction extends gradually.In order to understand the stress change of U-shaped ring of electric power fittings in the swing process more comprehensively,the static and dynamic analysis of U-shaped ring is carried out by using finite element software in this paper.Through the static analysis of U-shaped ring of power fittings by ANSYS Workbench finite element software,it can be concluded that under the loading condition of 8000 N,the contact area of upper and lower U-shaped ring is relatively concentrated,and the contact area has greater stress,the maximum stress is 1284.3 Mpa,the maximumcontact stress of upper and lower U-shaped ring is in the middle contact area,and the maximum contact stress is 906.92 Mpa and the maximum contact stress is 906.92 Mpa.Friction stress is 126.1 Mpa.Through dynamic simulation,it can be concluded that the equivalent stress of U-ring is always greater than that of U-shaped ring at an angle of 0-30 degrees when the U-shaped ring is loaded at 8000 N.With the increase of wear times,the wear amount of U-shaped ring increases gradually,but the wear rate is basically constant,and there is no trend of accelerated wear.The results are basically consistent with the experimental wear size data.The fatigue life of U-shaped ring is particularly important for the normal operation of power fittings,so the fatigue life of U-shaped ring of power fittings is analyzed in this paper.The fatigue life module of ANSYS Workbench is selected.The fatigue life of U-shaped ring under different loads is obtained by using elasticplastic assumption and Miner cumulative fatigue criterion and N-S curve.The minimum fatigue life of U-shaped ring under 4000 N load is 425 980 times,the minimum fatigue life of U-shaped ring under 6000 N load is 221820 times,and the minimum fatigue life of U-shaped ring under 8000 N load is 16620 times?Finally,the U-shaped ring of electric power fittings is analyzed by regression analysis.The U-shaped ring of power fittings is predicted by SPSS software under different conditions.The results show that the complex correlation coefficient of wear size of upper U-shaped ring is 94%,that of lower U-shaped ring is 94.2%,and that of residual strength of U-shaped ring is 98%.It shows that the regression model can better predict the wear condition of U-shaped ring.