| Under the weather of low temperature, sleet, wet snow, freeze weather, transmission lines icing will occur. Moreover serious icing will cause ice flashover, transmission lines broken, pour tower and other disasters, which will has serious threat on the safety operation of power grid and cause the great economic losses in society. Aiming at the problem of transmission lines icing, the on-line monitoring system for transmission lines icing based on smart grid research project was proposed in this paper. According to the operation of overhead lines and climatic factors, the system will monitor the situation and take the early warning measures. The study of the transmission line icing including the following:(1) Analysis of the research status of anti-icing technology for transmission lines is studied firstly. After the study of measures to improving the anti-icing ability of transmission lines at ice-covered area and the comparison of the anti-icing and de-icing methods of conductor and overhead ground wire, this paper proposes the research direction of anti-icing technology.(2) Based on the structural and mechanical analysis on the transmission line and towers, mechanical improved model for transmission line icing considering the state equation of overhead transmission lines is proposed. The model considering the length of lines, horizontal stress and vertical load of the straight towers can monitor icing and calculate the icing weight.(3) Based on the analysis of the characteristics of icing on overhead ground wires, the application of fluid mechanics and thermodynamics for ground wire forecast model is studied in this paper. After the analogy of the characteristics of conductors and overhead ground wires, a glaze-rim icing forecast model for ground wires based on dry-wet growth is proposed, which can be used to monitor the transmission lines icing.(4) This paper in detail introduces the structure deployment and working principle of the online-monitoring system for the smart grid transmission line. Then the icing monitoring module is embedded into the system based on the online-monitoring system, which contains the programming and database construction of the icing model, the display of icing monitoring, early-warning and so on. Examples show that the proposed mechanical icing monitoring model for transmission lines and icing forecasting model for overhead ground lines can accurately monitor and forecast icing of transmission lines. The online-monitoring models and the icing research methods proposed in this paper provide a theoretical foundation and practical working guidance for the prevention and management of the transmission lines. |
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