The Geometry Design And Dynamic Characteristic Analysis Of Jumper Wire On Tension Towers

Jumper wire is the conductor which connecting up two sides of tension towers and playing the role of power transmission. It is difficult for jumper wire to find out a method of fabricated construction in the project. If the sag is too small to reach the design distance,which may lead to electro-discharge between jumper wire and cross arm. While the sag is too large,the space between the jumper wire and the tower will be small under wind load. In addition,fatigue break of jumper wire happens often by reason of the constant wind load. It shows that the geometry design and dynamic characteristic analysis is of great importance.The thesis proposes a method to determinate the shape and calculate the length of jumper wire, which is based on the existing transmission line project. Also,the dynamic characteristic has been analysed on the base of the shape determinated by form-finding method. Firstly,it assumes that the initial shape of the soft jumper wire hanging with the same height is a quadric curve. The shape of the hanging jumper wire under self weight load is confirmed through force analysis,and the accurate length of jumper wire could be calculated. Then according to its initial shape, FE software ANSYS is used to build jumper wire modeling and calculate the displacement under its self weight,which can be compared with the results from form-finding method. After that,pulsatile wind load is applied to the finite element model of jumper wire in order to analyse its dynamic characteristic,and stress distribution of jumper wire can be got. The cause of jumper wire break-off fault can be inferred by comparing the frequency of wind load with the inherent frequency of jumper wire.The results indicate that form-finding method in this thesis is finely consistent with the simulated analysis result,which could be applied to calculate the length of jumper wire and it has of certain engineering practice meaning. The equivalent stress of jumper wire’s suspension points are always maximal under wind load for the reason of stress concentration phenomenon. It supposes that resonance phenomenon of jumper wire will be happened when some of the frequencies in pulsatile wind load are close to the inherent frequencies of jumper wire,which exacerbating the fatigue fracture of jumper wire.