Research On Experiments And Characteristics Of Rain-wind Induced Vibration On Transmission Tower And Line

Under rain-wind conditions,rain-wind induced vibration on high-voltage transmission lines often occur,which put influences on the aerodynamic instability of transmission tower-line system and even breaks the towers,and also challenge the power engineering communities how to ensure safe and stable operation of high –voltage transmission line.Rain-wind induced vibration on high-voltage transmission line is combined vibration of solid,liquids and gases,closely linked to electric fields.Therefore,in order to grasp the vibration characteristics of transmission tower line structure accurately,this paper analyzes the dynamic characteristics of transmission line structure model based on the test.Firstly,mechanism of rain-wind induced vibration on high-voltage transmission lines is described.Then an analytical model of rain-wind induced vibrations of the high-voltage transmission lines to investigate the effects of wind velocity,rivulet motions,raindrop velocity,and time varying mass on the vibration amplitude is validated.Then,based Galerkin weighted residual method and central difference method,the equation of analytical model is solved.Secondly,aiming at the characteristics of rain-wind induced vibration on transmission line,a rain-wind induced vibration test rig is made.The modal analysis of rain-wind induced vibration test apparatus homemade is studied by the method of experimental and finite element analysis.The analysis and conclusions can be used as references to change the natural frequency of the experimental apparatus by improving experimental apparatus structure and quality,and avoid the phenomenon of vibration in the experimental apparatus operating frequency range.Thirdly,under different load conditions,rain-wind induced vibration test apparatus homemade is used to simulate the rain-wind induced vibration on transmission line.The dynamic response law and influencing factors are analyzed by test data,and the vibration response of transmission line with the typical inclination and upper rivulet position under different wind speeds are obtained.Fourthly,hybrid substructure approach is used to investigate on aerodynamic characteristics of rain-wind induced vibration on transmission line.The transmission line(including the rivulet)and the flow field are considered as two substructures,the vibration response of the transmission line is measured through wind tunnel tests treated as the moving boundary condition of transmission line in the flow field.Only the flow field around the moving boundary is simulated by the CFD code to obtain the aerodynamic characteristics of rain-wind induced vibration on transmission line.Lastly,the transient aerodynamic lift and drag coefficients are applied to the transmission line to calculate the vibration response of transmission line.Then the comparison of the vibration responses is carried out between calculation results and experimental results.The research results show that the hybrid substructure approach is an effective approach to obtain the transient aerodynamic characteristics of rain-wind induced vibration on transmission line,and also provides an effective method to obtain aerodynamic characteristics which are inconvenient to be measured in the tests.The end,taking typical towers as the prototype,the aeroelastic models of transmission towers are designed by a new method with similarity criteria of structural dynamics to investigate the wind-induced response of transmission tower.Then,the dynamic characteristics of the aeroelastic models are analyzed by finite element analysis software and measurement system,which proves that the aeroelastic models are suitable.Lastly,wind tunnel test on the models are performed with different wind speeds and wind directions.The results show that the wind-induced response of the models increase with wind speed,and the response on Y-direction are evident.According to the test results,the characteristics of the wind-induced response and dynamic of typical transmission tower are obtained,which can be applied as references to designing and upgrading transmission tower on wind resistance.