Stability Evaluation of the Transmission Line by using Galloping Simulation
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International Journal of Precision Engineering and Manufacturing https://doi.org/10.1007/s12541-020-00399-5
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Stability Evaluation of the Transmission Line by using Galloping Simulation Yun‑Ji Oh1 · Jeong‑Hyun Sohn2 Received: 25 November 2019 / Revised: 10 July 2020 / Accepted: 30 July 2020 © Korean Society for Precision Engineering 2020
Abstract Galloping phenomenon is one of the vibrations caused by icing. If galloping phenomenon continues, short-circuit or ground fault may occur, so analysis of galloping phenomenon through research on transmission line stability is necessary. The DenHartog method, which is frequently used for the galloping stability determination of the transmission line, considers only the vertical movement of the transmission line. In this study, we analyze the motion of multi-degree-of-freedom objects, using a computer aided engineering program. We modeled transmission lines as a multi mass-spring-damper systems using RecurDyn, which is a multibody commercial dynamics analysis program to analyze the galloping phenomenon dynamically. Damping inside transmission line derived from the Rayleigh damping theory through the free vibration experiment of transmission line. ANSYS Fluent, a flow analysis program, was used to derive the aerodynamic coefficients for transmission line with asymmetric cross-section. Using the derived aerodynamic coefficient, we confirmed the galloping occurrence condition of DenHartog method and modeled the wind load acting on the transmission line to conduct galloping simulation. Through the analysis of the motion of a multi-degree-of-freedom transmission line, the occurrence of galloping was classified into ovoid and vertical trajectories, and the case of no galloping was defined as regular trajectory, and the range of angle of attack that causes the instability of transmission lines was defined. Keywords Transmission line · Galloping · Aerodynamic coefficient · Multibody dynamics
1 Introduction During the winter season, icing occurs where the crystals generated from freezing due to the cold air in the atmosphere attach to the transmission line passing through the alpine and snowy areas. Asymmetrically shaped icing sticks to the cross section of the transmission line to act like an airfoil, making the transmission line aerodynamically unstable. If a strong wind blows over the iced transmission line, excessive vibration may occur because of the self-weight and tension of the * Jeong‑Hyun Sohn [email protected] Yun‑Ji Oh [email protected] 1
Graduate School of Mechanical Design Engineering, Pukyong National University, 365, Sinseon‑ro, Namgu, Busan 608‑739, South Korea
Department of Mechanical Design Engineering, Pukyong National University, 365, Sinseon‑ro, Namgu, Busan 608‑739, South Korea
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transmission line, which is called galloping. The galloping phenomenon of the transmission line usually has a relatively low frequency of 0.1 to 1 Hz and a large amplitude of more than 1 times of the sag [1]. When vibration occurs because of galloping, arc
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