Abstract: The galloping of iced overhead conductors is one of the key factors for tripping fault of transmission lines, and threatens the security and stability of power system. It is thus needed to accurately capture such conductor’s galloping characteristics as displacement and frequency for solving the galloping problems. A 3-DOF (vertical, horizontal and torsional) galloping motion equation is established based on the Lagrange principle, and the modal perturbation method is used to describe the relative positions of the infinitesimals of galloping conductors. Considering the geometric nonlinearity of iced conductor’s galloping, the galloping motion equation is solved using the Newmark-β method combined with Newton-Raphson iteration, and an effective solving algorithm is proposed. The simulated displacement amplitude and frequency of the galloping in the case study are very close to the measured ones, which proves the effectiveness of the proposed model and algorithm. It is concluded that the galloping of iced conductors is a kind of self-excited vibration with vertical motion as principal and its frequency close to the natural frequency of the vertical vibration of the iced conductor system. The strain model and aerodynamic coefficients of the iced conductor galloping were improved significantly in this paper, and the modal perturbation method greatly reduced the calculation amount and improved the calculation accuracy of the galloping displacement, thus laying a good basis for accurate estimation of the line tripping probability caused by galloping.

Key words: iced conductors, galloping, motion equation, displacement, solving algorithm