Analysis On The Overhead Transmission Conductor Galloping Method Based On Tension Information

Overhead transmission line galloping is a self-excited vibration phenomenon generated when(iced) conductor excited by wind with low frequency(about 0.1 ~ 3Hz) and large amplitude(usually less than 12m), which will result in such accidents as broken conductor strands, wire disconnection, damaged fittings, phase short circuit, broken rods, down rods and other accidents, thus creating a serious threat to the safety of the power system. In early 2008, central and eastern China suffered a snow disaster rare in history and the transmission lines in many places had a varying degree of galloping, seriously affecting the safety and reliability of the power network. With the global environment and climate changing, the issue of transmission line galloping is becoming more and more prominent. In late 2009 to early 2010, more than 600 lines in China occurred dancing. Therefore, a real-time access to galloping situation is very necessary.The static response of the conductor is basis for transmission line operating state judgment and and dancing analysis. Based on the static equilibrium finite element transmission line equations, bare wires, wires by concentrated loads(equipped with anti-dancing device or spacer), iced conductors, wires static wind load were analyzed by mechanics, then it obtained each static equilibrium configuration and tension situation. As tension span and crossing span both considered, it can be used to analyze the multi-span continuous overhead wires.Currently, there are three main ways of on-line monitoring technique for galloping: the first is to achieve monitoring of the galloping through video capture technology; the second is through acceleration sensors; additionally, through tension sensors, angle sensors and other monitoring devices, we can also use the relationship between changes in length and in tension of the conductor(i.e. length method) to get the conductor galloping amplitude, which is more economical and feasible because of the monitoring devices installed at both ends of the transmission line. Therefore, based on the length method, aiming at the overhead transmission line galloping features, introducing equivalent axial tension, considering the windage yaw factors, taking the data measured at the connection of the tension sensor and the angle sensor in the conductor suspension point as the basic parameters, and combined with the line’s own parameters, this paper has established a calculation model for the monitoring of galloping.To verify the calculation model galloping monitoring, this paper applied FLUENT and ANSYS to simulate galloping simulation. Firstly, based on FLUENT software,this paper simulated the aerodynamic cladding of iced wire.This paper simulated a thin crescent aerodynamic characteristics iced conductor in the corresponding wind speed calculated and the results agree well with experimental results. Then build a overhead wire model in ANSYS environment, and then added the corresponding aerodynamic to make galloping, and finally obtained galloping conductor amplitude. Comparing simulation results with the results of the calculation model,it can verify the effectiveness of the theoretical model.