Simulation Of Fluctuating Wind Field And Study On Wind-induced Response Of Overhead Transmission Lines

Overhead transmission lines are sensitive to wind loads because of their long span and high flexibility.In view of the particularity of wind field and vibration characteristics of overhead lines in strong wind weather,the numerical simulation of non-Gaussian random process satisfying the law characteristics of strong wind is carried out based on the finite element model of overhead transmission lines,and the quasi-static vibration characteristics of overhead wires and the vibration and displacement laws under non-Gaussian pulsating wind fields are studied.The statistical law of typhoon wind field is given based on measured typhoon data.Non-gaussian random processes with different parameters are obtained by two numerical simulation methods.By using nonlinear Johnson transform and AR method,the skewness and kurtosis of target pulsating wind field were set as 0.767 and 4.06,and a non-Gaussian random process satisfying the power spectrum and higher-order statistical law was obtained.On the basis of Kaimal power spectrum,the frequency-wave number spectrum is obtained.Through translation transformation and FFT transformation,the random process satisfying the power spectrum and edge probability distribution is obtained,and the non-Gaussian random process is obtained which is continuous in space and time.The results show that both methods can meet the requirements.The finite element simulation model of transmission tower line is established and the modal analysis of the structure is carried out.The tower adopts BEAM three-dimensional thin-wall beam unit,which is fixed at the bottom and rigidly connected as a whole.The overhead wire adopts CABLE280 cable unit,which is connected with the tower through the solder joint,and the displacement constraint is set.The finite element simulation shows that the local and bottom of the tower are prone to distortion and damage in vibration,and the vibration frequency of the transmission tower line is quite different.The vibration of overhead lines is complex and mainly consists of first-order modes and second-order modes.In addition to the natural vibration frequency of 0.5～1.5Hz,there are different combinations of in-plane vibration and out-of-plane vibration.Based on the finite element model of transmission tower lines and the pulsating wind field with non-Gaussian characteristics,the vibration process of overhead lines under different wind angles and wind speeds is analyzed,and the displacement distribution range of overhead lines in vibration is determined.The time-frequency characteristics of overhead line vibration and the displacement difference between hanging point and overhead line are obtained.In the process of vibration,the out-of-plane response is greater than the in-plane response,and there is a 0.3m displacement along the line direction.The natural vibration frequency is mainly 0.5～1.5Hz,and the power spectrum at the line hanging point has energy accumulation at the frequency nodes of 3Hz and 6Hz.The displacement law of overhead line is very different from that of the tower and hanging point,so attention should be paid to it.