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Received Feb 20, 2017; Revised Jun 4, 2017; Accepted Jul 9, 2017
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1. Introduction
China is a mountainous country. The mountain area accounts for more than 60% of the land area. The mountainous southwestern region is rich in hydropower resources and it is also the main power generation area of the West-East Electricity Transmission Project. Most of the transmission lines will cross valleys, rivers, and micrometeorological areas in mountainous southwestern regions, where the conductors are easily ice-coated in winter. Under certain conditions, the ice-coated conductor will produce large amplitude and low frequency self-excited vibration, which is called galloping [1, 2]. Galloping may cause transmission lines’ collision, fittings failure, line trip and power outage, or even line breaking, tower failure, and other great dangers [3]. In 2008, the biggest snow and ice disaster in this century hit the southern region of China, which led to transmission lines icing on a large scale and seriously affected the normal operation of the power system. Since the aerodynamic coefficients of ice-coated conductors are the basis for the study of galloping, it is necessary to investigate the aerodynamic characteristics of the ice-coated conductors in ultrahigh voltage transmission lines.
There are lots of researches about the aerodynamic characteristics of ice-coated conductors. As early as 1932, Den Hartog [4] proposed the vertical galloping mechanism of ice-coated conductors. Nigol et al. [5–7] proposed the torsional motion mechanism and the protective measures of galloping by the experimental study of the ice-coated conductors. Gurung et al. [8] and van Dyke and Laneville [9] carried out a full-scale test to obtain the aerodynamic characteristics of...