Research On Aeolian Vibration Control Of Transmission Lines By New Type Of Antivibration Hammer Based On PTMD Principle

When the airflow passes through both sides of the transmission line,vortices that are arranged asymmetrically and in opposite directions are generated,which alternately act on the upper and lower surfaces of the transmission line,causing the transmission line to vibrate up and down in the vertical direction,resulting in aeolian vibration.As a mass tuned damper,the anti-vibration hammer can well control the aeolian vibration on the transmission line.Compared with the traditional non-pounding mass tuned damper(TMD),the pounding mass tuned damper(PTMD)will increase the impact energy consumption and have more excellent vibration damping performance.Based on this theory,this paper applies PTMD to the aeolian vibration control of transmission lines.Designs a new type of anti-vibration hammer-PTMD,and establishes a mechanical model,transmission line-PTMD anti-vibration hammer system vibration test and numerical calculation Preliminary discussion on the control performance of PTMD anti-vibration hammer on the breeze vibration of transmission line.The main contents and conclusions of this paper are as follows:(1)Analyze the collision mechanics models obtained by scholars at home and abroad,select the collision model suitable for the characteristics of the anti-vibration hammer,and establish the PTMD anti-vibration hammer mechanics model as a collision-spring-damping-hammer head system.The interaction force between the PTMD anti-vibration hammer and the transmission line is deduced,and the specific expression is given,and the force of the transmission line and the PTMD anti-vibration hammer is related to the displacement and speed at the collision position on the transmission line.Finally,the dynamics method is used to establish the transmission line motion equation,the vibration response of the transmission line is subjected to mode superposition analysis,and the vibration response time parameter equation of the transmission line is obtained.It is known that the collision force between the transmission line and the anti-vibration hammer could be converted into power transmission.The damping of the line achieves the effect of vibration reduction by increasing the damping of the transmission line.(2)The vibration damping performance of the PTMD anti-vibration hammer is studied through the excitation test of the transmission line-PTMD anti-vibration hammer system.The conclusions is as follows.(1)Design the test wire suspension-fixing device and the wire-loading device,and conclude that the natural frequency of the wire fixing spring-wire system increases with the increase in the stiffness of the fixing springs at both ends of the wire.(2)Anti-vibration for PTMD the impact characteristics of the hammer are analyzed,and the impact frequency between the transmission line and the anti-vibration hammer is equal to the excitation frequency in the test.(3)The new PTMD anti-vibration hammer is better than the TMD type anti-vibration hammer with the same hammer head quality.(4)Analyze the impact of the quality of the PTMD anti-vibration hammer and the length of the steel-cored aluminum strand on the damping rate.It is known that the damping rate increases with the increase in the mass of the hammer.Trend and the PTMD anti-vibration hammer has the best damping effect on the transmission line when the length of the steel core aluminum stranded wire is 150mm.The fourth-order Runge-Kutta method is using to solve the transmission line vibration equation in the Mathematic numerical calculation software,and the calculation results are compared with the transmission line-PTMD vibration-proof hammer excitation test.Found that the results between the two are highly similar.Later,study the influence of different installation positions and number of PTMD anti-vibration hammers on the transmission line on the aeolian vibration control ability of the transmission line.Within the area of 1/3 L_s～1/2 L_s away from the suspension position of the transmission line,installing different numbers of PTMD anti-vibration hammers in the best installation area has little effect on the vibration control ability of the transmission line,and installing one PTMD anti-vibration hammers can be control the transmission line vibration so well.