Research Of Transmission Line Aeolian Vibration Based On Dynamic Method

Transmission line aeolian vibration is a general concern problem around the world. Because the vibration is high-frequency and durative, it becomes an important security risks for transmission line, and limits to reduce conductor costs. With the construction of 1000kV Ultra High Voltage in China, the conductor is higher, more flexible and larger capacity, which is not conducive to aeolian vibration resistance, and put forward higher requirements for design.Different from the energy balance method traditionally, dynamics method is employed to research on the transmission line aeolian vibration and vibration control. The dissertation includes the following main content. Numerical simulation of aeolian vibration based on computational fluid dynamics; dynamic model of transmission line-dampers system is modeled and solved by finite difference method; the forced vibration experiment for transmission line with and without dampers attached; study on fatigue life of transmission line aeolian vibration based on the probability distribution of wind speed and direction. It aims at establishing a set of analysis method for transmission line aeolian vibration based on dynamics method and fatigue life.The numerical simulation on aeolian vibration phenomenon of the transmission line is implemented by using computational fluid dynamics (CFD) method. The classical results of wind tunnel experiment are reproduced by CFD, and self-limit phenomenon is discussed. Then based on priori hypothesis of amplitude, wind power input in different wind fields which have different turbulence intensity has been obtained for a single two-dimensional transmission line model.Transmission line vibration test are designed independently reference to IEEE standards. Vibration intensity about conductor with FR-3 damper is compared with FR-4 damper attached through data analysis. The impact of vibration intensity by tension is asol studied by the test. In the final experiment, a set of experiment are designed for investigating the effect of anti-vibration by damper number, damper location and mixed installation.Based on CFD numerical simulation and vibration test, aeolian excitation, equivalent self-damping ratio and damper impedance are deducted, and conductor-dampers dynamic equations are modeled. The fourth-order finite difference method and the iterative algorithm are employed to solving the aeolian vibration dynamic equations, and then the steady amplitude & dynamic benting strain can be obtained for ervery point. The calculation software named AVFDP is programed using fortran90. Compared with test and classical date, present result is correct and accurate enough. By using AVFDP program, the system dynamics charactors, the response of transmission line aeolian vibration and the parameter sensitivity can be analysed.In the last part of dissertation, formula of fatigue life of transmission line aeolian vibration is deduced. The vibration displacement amplitude is related with fatigue life by this formula which can consider the probability distribution of wind speed and direction. Take fatigue life as an evaluation index, the sensitivity of a series of parameters is researched, and optimal dampers location can be obtained.Becase of complexity of aeolian vibration and ponderance of fatigue failure, transmission line aeolian vibration has been to attract the majority of the attention of scholars. But there is a long road to completely solving the problem. This dissertation presents a new approach, and provides the reference to the study of vibration mechanism, analysis method and control strategy.