Study On Subspan Oscillation Of Multi-bundle Conductors

Because of the vast territory, our country has the case of unbalancement of distribution and development of power resources. Along with economic development and social progress, demand for electricity improved. Increasing construction of EHV, UHV power grid has become an inevitable development. The construction of transmission line need to consider the influence of many unfavorable factors, the wire oscillations is one of them. Subspan oscillation is a unique oscillation form of multi-bundle conductor,which is caused by the wake shielding effect. Long-term subspan oscillation will lead to fatigue and abrasion of spacers. Oversized amplitude may cause collision even rupture of sub-conductors. Nevertheless, the control of subspan oscillation relies on experience mostly, there is no clear prevention regulations. So it is very necessary to research the subspan oscillation of multi-bundle conductor. In this paper, on the basis of domestic and foreign scholars the research are as follow:1. Based on the basic theory of CFD, using FLUENT to simulate the wake shielding effects of cylinder. Researched wake shielding effects of single cylindrical wire and Analyzed if superposition principle of wake can happened.2. Based on the consequence of CFD gives the aerodynamic coefficients of conductors; combining the quasi-steady theory and the actual wind speed formula gives the aerodynamic force formula..3. Numerical simulation was conducted about subspan oscillation of four-bundle conductor. A three-span model with four-bundle was built using the software ANSYS. Static analysis was done to find the shape and verified the correctness of the model. Then modal analysis and dynamic analysis was done to the modal. Got the vibration frequencies, the displacement and some other informations. Influences of subspan length, wind speed, angle of wind, bundle spacing and operation strength were studied afterward.4. Proposed two simplified models of subspan oscillation, segment modal and oscillation modal. Derived the stiffness of the simplified models. Subspan oscillation of different conditions was studied using the simplified models.