Early Warning Method of Transmission Tower Considering Plastic Fatigue Damage Under Typhoon Weather

Strong typhoon can cause low-cycle fatigue damage to transmission towers throughout the impacted area and initiate tower collapse, leading blackout to the power system. As a result, it is necessary to develop an early warning method of transmission towers to help power companies make effective emergency response planning to minimize economic losses in advance of an approaching typhoon. In view of the existing models for predicting component failure probability overly relying on historical data and the lack of early warning methods for transmission towers, a new early warning method based on the failure process of transmission towers under typhoon disasters is proposed in this paper. First, a typhoon warning start point (TWSP) is selected to ensure prediction accuracy of transmission tower failure probability and timeliness of personnel and materials deployment for power companies, then mesh generation is applied to determine the risky tower affected by typhoon at the TWSP. Second, the duration time and changing wind speed of the typhoon on the risky tower are calculated according to typhoon short-time forecast information at the TWSP, and the wind speed is revised in the light of microtopography. Finally, the low-cycle fatigue damage mathematical model based on fatigue damage theory is combined with the improved Poisson formula to attain the failure probability of the transmission towers. In addition, since typhoon develops and dissipates with time, the typhoon path is tracked to correct the low-cycle fatigue damage value on the basis of typhoon nowcasting information, and the failure probability of transmission towers are constantly updated until typhoon departs from the risky zone. The proposed method is applied to the modified IEEE 30 system. The numerical results verify the proposed method is reasonable and effective.