A Probability Model of Ice Storm Damages to Transmission Facilities

A model based on the extreme value theory and copula functions is proposed to assess the probability of potential damages to transmission lines and towers during ice storms. Generalized Pareto distributions of freezing precipitation and wind speed are first derived. Copula functions are then employed to derive the joint probability distribution of ice and wind loads on both transmission lines and towers. Based on the proposed model, probabilities of transmission-line damage and tower collapse can be calculated. The validity and accuracy of the proposed model are verified by comparing the numerical results given by the model with historical data of a real transmission system during two serious ice storms in China. The proposed model will be highly useful for assessing efficacy of power systems emergency controls during ice storms.