Wear Behavior Of U-shape Ring Of Transmission Line Under Strong Wind And Dust Environment

The U-shaped ring of UHV power transmission line plays a vital role in ensuring the normal operation of the transmission line.However,due to the special situation of Xinjiang's geographical location and terrain,special environmental conditions have been created,especially in the "Thirty Miles of Wind District" In the "Bali Wind District" section,this 750 KV transmission line is severely tested.The U-shaped ring is expected to have a service life of 20 years.However,in 2012,Xinjiang Tuha line suffered severe wear and tear when it was put into use for one year.The replacement of 1747 sets of U-rings not only caused an increase in costs,but also caused serious economic losses and inconvenience to residents due to power failures.In order to more realistically and effectively study the wear mechanism of the U-ring.firstly,experimentally,according to the actual conditions of the "Bali Wind District",the parameters are designed to carry out different loads,abrasion times,loading frequencies and different sand particle sizes.The surface response method was used to optimize the wear test parameters of the U-shaped ring,and the remaining perimeter after wear was used as an evaluation index.A Box-Behnken regression model was designed with three factors of loading load,number of swings and frequency.The BP neural network and regression were used.The prediction results of the models were compared,and the optimized parameters were verified by experimental methods.At the same time,the organization and performance of the U-shaped ring under different swing times were analyzed.The results show that the complex correlation coefficient R2 of the regression model is 0.9900,and the complex correlation coefficient R2 of the BP neural network is 0.9986.The number of oscillations has the most significant effect on the remaining perimeter.With the increase of the number of oscillations,U-ring wear scar surface cracks and pitting pits gradually increase,and the particle size and hardness of the structure at the edge of the material gradually decrease.The experimental parameters that have the most influence on the U-ring are: the load is 0.8 tons,the number of swings is 160,000,the frequency is 1,and the minimum remaining perimeter that can be predicted is 39.51 mm.The wear test of the U-ring was carried out using a reasonable experimental scheme.After the wear was completed,the remaining dimensions of the U-ring were studied under different wear times.At the same time,the LEO-140 VP scanning electron microscope,metallographic microscope and HXD--1000 TB micro-hardness tester observes and measures the worn surface and sides,characterizes the micro-morphology and Vickers hardness of the worn surface,and then studies its wear mechanism.The results show that: 1)The remaining ratio of the U-ring cross-sectional size decreases with the number of wears.2)After the wear,the hardness of the surface away from the wear scar increases with the number of wears;the hardness at the wear edge decreases with the wear.3)The morphology of the wear scar surface after wear,the pitting pits and crack marks first appear on the wear scar surface,which gradually transform into furrows and flaking.Adhesive wear is dominant in strong wind environment,accompanied by oxidative wear and abrasive wear;abrasive wear is dominant in sand and dust environment.4)When the length of the remaining perimeter of the U-ring is0.15-0.25 mm in the sand particle size,it has a small remaining perimeter at 20,000 times,40,000 times,60,000 times,and 80,000 times.Using finite element software,according to the actual line design parameters,a finite element model of the U-ring is established,and the structure is subjected to static and dynamic analysis.The calculation results show that in the static analysis,the maximum stress position of the U-shaped ring is the center contact portion,and the maximum equivalent stress is 1482 MPa.There is slip between the upper and lower U-shaped hanging rings,and the slip distance is 0.8um;In the U-shaped ring,the deformation of the sixth order is the most serious.Under the combined action of horizontal and vertical loads,the frequency of the maximum displacement amplitude is2700 Hz,the amplitude value is 1.3046e-4mm,and the stress value is 33.481 MPa.The time frequency is close to the natural frequency of the structure,and the structure is prone to resonance.Under the fluid-solid coupling effect,simulation analysis shows that the flow velocity,flow and sand particles in the flow field will cause the erosion and wear of the U-ring to change.Among them,the wind speed is 30 m / s,the flow is0.01 kg / s,and the sand particles U-ring wear is the worst when the particle diameter is0.15mm-0.25mm?...