Risk assessment for power system static security based on fuzzy modeling of weather conditions

The fuzziness of weather conditions and boundaries between neighboring climatic regions exerts a great influence on the modeling of failure rates of overhead lines. This paper introduces the failure rate multiplier (FRM) to reckon in the weather impact and establishes a fuzzy inference system with load of wind (LW) and load of icing (LI) as the input logic variables. On this basis, the FRM and thus the time-varying failure rate are obtained through the Mamdani's min-max-centroid method. Then, the time-varying restoration time and failure rate are used to simulate the situation in which a line traverses several climatic regions considering fuzzy boundaries. Finally, the weather-related failure rate and restoration time are applied to risk assessment for power system static security. Simulation results on the New England 39-bus test system demonstrate the necessity of incorporating weather factors into risk assessment, and prove the feasibility and effectiveness of the proposed method.