Wind and ice loading risk model and fuzzy forecast for overhead transmission lines

Power systems suffer tremendous economic loss in extreme ice disaster weather, suggesting that it lacks immediate precaution system. According to standards Q/GDW 179-2008 and IEC 60826-2003, the wind and ice loading design curves for transmission lines were built up. According to the random character of load-strength and load-strength interference theory of transmission line, a time-dependent wind and ice loading risk model was established. Unreliability and fault rate can be calculated based on the proposed model, which indicates the risk for cluster fault and common fault of short-term reliability. Furthermore, the line loads were divided into five states, which could reflect the risk margin of the line. Short-term wind and ice load risk forecast was conducted based on fuzzy theory, and presented risk measurement on time scale, which could provide precaution information for operator.