Research On Wind Load Parameters Of Transmission Line Based On Field Measurement And Numerical Simulation

With the rapid development of China’s economy,the demand for power resources has risen sharply.As the transmission line system has the characteristics of high altitude,large span and light structure,it is highly sensitive to strong wind load.Located in complex environment,the large-scale projects are vulnerable to severe weather conditions under strong wind disasters In addition,mountainous topography can cause the sudden change of local wind field near the ground,resulting in the transmission line structure to suffer wind loads that are far beyond the design level,which may cause the collapse,flashover or other failures.At present,the codes of overhead transmission lines mainly rely on the common wind field in the calculation of wind load of transmission lines.However,the influence in extreme weather and under mountainous topography such as hills is seldom mentioned,which leads to the unreasonable value of wind load model parameters.Therefore,it is necessary to further optimize the wind load of transmission line design under strong wind and micro-terrain conditions by combining with field measurement,numerical simulation and other methods.In this paper,the multi-point synchronous monitoring system and wire response monitoring system established by our research group in the coastal area of zhoushan were firstly used to collect the field measured data up to one and a half years to screen out the strong wind weather and analyze the turbulence characteristics and tower line dynamic characteristics of the strong wind field in hilly terrain.Secondly,coupled WRF-LES multi-scale typhoon numerical simulation was used to simulate the hilly region,and the surrounding flow field of the transmission line was analyzed and compared with the field measured data of the typhoon.Thirdly,based on the field measured data and numerical simulation results in strong wind,the values of non-uniform factor of wind pressure,span reduction factor and wind load adjustment factor under hilly terrain are calculated,then the corresponding proposed formulas are fitted and compared with the relevant formula in domestic and foreign design code of transmission lines to analyze and discuss the rationality of the proposed formula and the codes.Finally,the distribution parameters of probability density model of non-uniform factor of wind pressure and wind load adjustment factor are estimated and updated by using bayesian theory and field measured data samples.