Mitigation of conductor line galloping by a direct cable-connection to non-conductive composite power pylons

Abstract

Steel lattice towers with suspended insulator strings are typically used to carry high-voltage overhead transmission lines. The installation of non-conductive power pylons made of glass fibre reinforced plastics enables a direct cable-pylon connection, as the composite structure acts as an unibody insulator. At the same time, wind-induced vibrations, such as the severe cable vibration phenomenon galloping, will consequently be directly transferred to the slender composite mast structure, potentially leading to extensive damage. The aim of the study is therefore to investigate the galloping behaviour of iced conductor lines with regard to different cable support conditions. Furthermore, additional damping in the composite power pylon structure is assumed to mitigate conductor line galloping and therefore reduce the risk of phase flash-overs between adjacent conductor lines. A numerical galloping simulation is carried out in order to evaluate the effect of a rigid cable-pylon connection with enhanced damping properties on the cable vibration amplitudes. A pylon-cable system, consisting of 3×300 m spans, is investigated. It was found that the support conditions of the conductor lines have a significant influence on the galloping mode, the vibration amplitudes and the orientation of the characteristic galloping ellipse. The addition of damping to the pylon decreases the vibration amplitudes slightly and leads to a re-orientation of the galloping ellipse.

Research on transmission line dance monitoring and early warning system by fusing multi inertial sensors

“…Literature [15] balanced the wind load with axial periodic displacement excitation to study the dance collision phenomenon on overhead lines with a single conductor and showed that the main factor affecting the dance is the periodic variation of the transmission line system parameters, explaining the cause of the dance phenomenon on overhead line conductors. Literature [16] in order to study the effect of ice lines on different cable support conditions, a pylon-cable system consisting of 3 × 300 m spans was investigated by evaluating the effect of rigid pylon-cable on the enhanced damping properties of the cable vibration amplitude to solve the cable vibration phenomenon. Literature [17] used the newma-beta incremental method and newrt-raphson nonlinear iterative algorithm to solve the discretized system of ice line dynamics equations, analyzed the causes of large-amplitude, lowfrequency and self-excited dances of ice-covered transmission lines, and gave a method to minimize the calculated dance values.…”

“…The above formula (16), formula ( 17), E for the conductor's modulus of elasticity, n for the number of half-waves, g for the acceleration of gravity, l for the line's stall distance, A for the cross-sectional area of the wire, m for the mass per unit length of the conductor, 0 T for the initial tension of the conductor, T  for the incremental tension of the conductor.…”