Nonlinear Numerical Analysis And Stability Study On Galloping Of Iced Conductor

Galloping of conductor is a very complex process that is affected by many factors movement occurred in the harsh natural conditions. Galloping endanger the safe operation of the transmission line greatly, ranging from wire whip attack, burns, broken stocks, etc., will cause severe break down the tower, line tripped, causing blackouts, bring significant economic losses to society. Researching the galloping mechanism, dancing shape and stability issues of iced conductor has important significance in the prevention of accidents and actively galloping phenomenon. Research on single-span iced conductor, galloping studied from several aspects of the model, the parameter simulation, displacement response and stability. The main research contents are as in the following:1. Considering rotational freedom and nonlinear geometric characteristics of the iced conductor, a nonlinear finite element model of the conductor was established. The damping matrix, wind load vector and coordinate transformation matrix of model were derived, and the boundary conditions at both ends of a single span of transmission lines were given.2. Gambit software was used to establish physical model of iced conductor. The CFD software of Fluent was used to analyze the aerodynamic characteristics of crescent section iced conductors, obtained aerodynamic coefficients curve and analyzes the impact of ice thickness and relative wind speed aerodynamic coefficients.3. The inherent characteristics of the transmission line were analyzed, to obtain the natural frequency and vibration mode of the conductor. Based on the nonlinear finite element equation of iced conductor galloping, the Newmark time integration method and the Newton-Raphson nonlinear iteration method were used to simulate displacement responses of conductor galloping, and the effects of initial stress and velocity to response of conductor galloping were analyzed.4. According to the two degree of freedom differential equations of conductor galloping, the differential equations were derived to obtain characteristic equation, and the Routh criterion was used to analyze the stability of conductor. To obtain the critical wind speed of iced conductor galloping through programming, finally the influence of span and stress on the galloping critical wind speed were analyzed. Study on the influence of the parameters is of great significance for the design of transmission line and the galloping prevention.