Determination of the power transmission line ageing failure probability due to the impact of forest fire

With increased occurrences of a forest fire, the short-term reliability of power transmission lines needs to be re-evaluated considering the impact of forest fire on the ageing of transmission lines. How to include the impacts from a forest fire on line ageing in a comprehensive way becomes an important issue for the study of line failure probability. In this study, a method is proposed to evaluate the impact of forest fire on line ageing degree based on dynamic heat balance equation and Weibull distribution. The method will help maintenance staffs to assess the damage level of transmission lines. The method is tested by a contrast experiment and a case study with real meteorological data. Simulation results show that forest fire can greatly threaten the reliability of power transmission lines, while during this process flame characteristics, wind and load ratio could be the major factors that affect the line reliability. With the results obtained, this study also provides the system operator with valuable instructions on how to reduce the damages caused by fire to transmission lines.