| The wind load is an important external load of the tower-line system,and the influence of the coupling effect between the lines and the tower,and the coupling between the wind and the lines on the wind-induced response of the tower system is difficult to be considered by theoretical analysis and test methods.Therefore,it is of great engineering significance and economic value to study the wind-induced response of the tower-line system and the effect of tower-line coupling.In this paper,the wind-induced response of the tower-line system was obtained from fullscale measurements.A finite element analysis model of the Ultra High Voltage(UHV)transmission system is established,and the time domain method and frequency domain method are used for the calculation of wind-induced response and the gust loading factors of the tower-line system.The finite element simulation method of the wind load of the tower-line system in skewed wind directions is explored.The results show that the wind-induced response of the prototype tower has a significant reduction and the natural vibration frequency has decreased after hanging the line in the wind direction of the line.The gust loading factors of the current code is conservative,and it is difficult to reflect the torsional effect of the Tshaped transmission tower.It is difficult to represent the cross-wind vibration of the towerline system by finite element simulation method.An aeroelastic model of the UHV transmission line was designed and fabricated using the discrete stiffness method.The results show that the test values of the wind-induced response of the tower,the tension and span displacement response of the conductor are closer to the finite element calculation results.The cross-wind vibration is more obvious,and the most unfavorable wind angle occurs at 75 degrees.The difference between the test values and the finite element results is that the former has a higher degree of cross-wind vibration.The effect of aerodynamic damping on the wind-induced response of the tower-line system was studied.The aerodynamic damping of the conductor at different wind speeds was identified.The wind-induced response of the tower-line system is calculated by using three methods considering the test value of aerodynamic damping,the theory of relative motion of wind and conductor and ASCE 74-2020 code.The results show that the identified values of aerodynamic damping are positively correlated with the wind speed.The results of the three methods of considering aerodynamic damping are close to each other,and the damping value of ASCE 74-2020 is slightly higher.The small percentage of lines load makes the windinduced response of the tower less influenced by the aerodynamic damping,and the aerodynamic damping of the transmission line cannot be reflected in the wind-induced response of the tower.The study of the coupling effect of the tower-line system is carried out with two cases:“Tower Load Control”(TLC)and “Lines Load Control”(LLC),and the parametric analysis of the coupling effect is carried out.The results show that the tower-line coupling effect will weaken the wind vibration of the tower,which is reflected in the reduction of wind-induced response and gust loading factors.The TLC case shows a strong coupling effect,which is most obvious in the line direction.The weakening effect of the coupling effect positively related to the wind speed.The LLC case shows a weak coupling effect.Besides,the higher lines load ratio makes the wind-induced response of the tower system affected by aerodynamic damping to a higher degree,especially in the direction of cross line.The existence of aerodynamic damping will weaken the tower-line coupling effect. |
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