Finite Element Analysis Of Galloping And Anti-galloping Of Transmission Line Based On Curved Beam Theory

Under the stable wind, the iced transmission conductor will appear low frequency and large amplitude vibration which is usually called as galloping. The galloping of transmission conductor will cause electric accident, such as flashover, short circuit, hardware damage and so on, creating enormous economic loss. At the present time, the finite element analysis of galloping of transmission line is mainly based on cable element theory that neglects the bending rigidity and is discrepant with bending rigidity of transmission line. Based on curved beam theory considering tensile stiffness, bending stiffness and torsional stiffness, this paper does some research on galloping and anti-galloping of transmission line.â‘ The analysis of curved beam mode of iced single line. Based on curved beam theory, the curved beam model of 6-DOF node single line is established and the kinetic equation is derived with the principle of virtual work. Nonlinear of single line is analyzed through Matlab programming. The results of examples show that the curved beam model of single line is more accurate than cable element modle.â‘¡The analysis of curved beam mode and torsional stiffness of iced bundle lines. Firstly, the spacer was assumed as rigid body. The curved beam model of bundle lines was formulated according to the displacement compatibility conditions. Moreover, the kinetic equation is derived through virtual work principle. Secondly, nonlinear property of bundle lines is analyzed through Matlab programming. The results of examples turn out that the model of bundle lines based on curved beam theory is feasible and advantageous. Based on this, the curved beam model is used to calculate torsional stiffness of bundle lines. The results of bundle lines'parameter analysis show: the more spacers there are, the greater torsional stiffness is; the greater the space is, the greater the torsional stiffness is; the greater the sag is, the greater the torsional stiffness is; the closer it is away from the tower- line connection point, the greater the torsional stiffness is.â‘¢The finite element analysis of transmission line galloping. According to the curved beam model and kinetic equation of single line and bundle lines, the time history of galloping of transmission line is analyzed through Matlab programming. The results of examples further prove that the curved beam model of transmission line is accurate and advantageous. Analyse of the wind speed, span, tension and other factors'effects on the initial amplitude of galloping show: the greater the span is, the greater the amplitude is; the greater the initial tension is, the smaller the vertical amplitude is; the greater the initial tension is, the bigger the torsional angle is; Consider wire bending rigidity, vertical amplitude and lateral vertical amplitude will increase, torsional angle will decline; galloping vertical amplitude of bundle lines is much bigger than the single line, and torsional angle of bundle lines is much smaller than the single line.â‘£The finite element analysis of anti-galloping of transmission line. Detuning pendulum mass matrix and stiffness matrix are derived to analyze the anti-galloping of the detuning pendulum. The results show that detuning pendulum only decreses the galloping of Nigol but increases the vertical galloping amplitude of Den Hartog. Finally, the critical wind speed of galloping of transmission line is solved by stability theory. Moreover, effects of span, tension and detuning pendulum on the critical wind speed are analyzed. The results of analysis show: the critical wind speed declines as the span and the initial tension increase; the gravity of hammer of detuning pendulum has little effect on critical wind speed but pendulum length plays great effect on critical wind speed.