Research on Wind-Induced Fatigue of Substation Disconnect Switchgear Structures

Substation pillar-type switchgear structures are important electrical equipment in the power transmission and transformation system. These structures are characterized by a large top mass, low overall stiffness, and low natural vibration frequency, and are prone to fatigue damage under long-term wind loads. At present, studies on wind-induced vibration fatigue of substation disconnect switch structures are relatively limited. In this paper, a numerical model of the substation disconnect switch structure is established on the basis of static tests, and wind loads are determined according to wind tunnel test results. The Weibull distribution model and the mixed distribution model (Weibull distribution + GPD distribution) are adopted to characterize the wind-speed probability distributions in large-scale steady strong-wind regions and typhoon-prone regions, respectively. Fatigue damage calculation and life prediction are carried out for the fatigue-critical positions of the disconnect switch structure. The results show that the windward and leeward M16 bolts at the flange joint suffer fatigue failure within the 50-year design service life. In large-scale steady strong-wind regions, the predicted fatigue lives of the critical M16-① and M16-⑤ bolts are 8.28 years and 8.48 years, respectively; in typhoon-prone regions, their predicted fatigue lives reduce to 0.87 years and 3.01 years, respectively. The research findings can provide a reference for the anti-fatigue design of flange joints for substation disconnect switch structures.