Study On Tearing Reasons And Response Measures Of Roof Silicone Rubber Composite Insulator For High-speed Train

The umbrella skirt of the silicon rubber composite insulator on the roof of the EMU will be repeatedly deflected under the action of continuous wind load.The continuous vibration can cause damage or even tearing of the insulator umbrella.The damage of the umbrella skirt will increase the probability of insulator flashover accidents.In order to analyze the tearing of the roof insulator umbrella skirt of the 200km/h EMU,this thesis simulates the interaction between the flow field near the insulator and the deformation of the insulator umbrella skirt based on the theory of fluid-solid coupling.Analyze the causes of needle-prick points/pits on the surface of the insulator shed,combine the fatigue crack growth mechanics and the microscopic properties of silicon rubber materials,analyze the growth of the shed surface cracks under alternating loads,and qualitatively analyze the energy changes and the crack growth process Crack growth rate.Carry out the pollution flashover characteristic test of pre-judged cracked insulators,compare the flashover voltage tolerance values of insulators with different defects,and analyze the differences in flashover characteristics of cracked insulators of different sizes.The tearing process of the umbrella skirt of the roof insulator of the EMU and the reasons for the tearing of the umbrella skirt are analyzed,and corresponding countermeasures are proposed.In order to solve the problem of the edge tearing of the silicone rubber insulator umbrella skirt on site,the epoxy insulator with higher mechanical strength was used to replace the silicone rubber insulator.In the wind and sand environment,the edge of the epoxy resin insulator umbrella skirt may have local corrosion.The influence law of shed edge erosion characteristics.Based on fluid mechanics and Finnie theory,track the movement trajectory of sand particles near the insulator in a wind-sand environment,analyze the process of sand following the high-speed airflow bypassing the insulator or directly colliding with the surface of the insulator,and analyze the energy loss process caused by the impact of sand particles on the edge of the insulator umbrella.Simulation analysis and test results show that when the diameter of the sand particles is 0.25-0.50 mm,the wear of each umbrella skirt between40°-60° is the most serious,and the wear of No.7 umbrella skirt is the largest.The simulation model provides a reference for studying and analyzing the optimization of the epoxy insulator umbrella skirt structure in the wind and sand environment.The height of the roof insulator of the EMU is greater than 3m from the ground,and the diameter of the sand particles at this height is less than 0.25 mm.The sand particles have little wear on the edge of the umbrella skirt of the epoxy resin insulator.When the hydrophobicity of epoxy resin insulators decreases,it is easy to cause flashover accidents.Therefore,silicone rubber insulators with higher hardness are used instead of epoxy resin insulators.The coupling theory analyzes the deformation characteristics of hard silicone rubber insulators,and compares them with soft silicone rubber insulators,analyzes the degree of deformation and the difference in stress concentration at the edge of the insulator umbrella skirt;analyzes the insulator umbrella skirt hardness,wind speed and direction,and entry The influence law of outbound acceleration on deformation characteristics,the results of this thesis can provide reference for the optimal design of roof insulator structure of EMU.