Analysis of Stress and Fatigue Life of Circuit Breaker Opening and Closing Spring

Energy storage spring is an important component of the circuit breaker’s spring operating mechanism. A three-dimensional model of the opening spring and closing spring of the 126kV circuit breaker was established through COMSOL, and the stress and strain distributions in the stored energy state and the non-stored energy state were obtained through finite element calculation. The results show that the stress and strain of the inner ring of the spring is significantly greater than that of the outer ring, the maximum stress of the spring is lower than the yield strength of the spring steel, and the stress level meets the requirements. Based on the stress calculation results, the fatigue life analysis is carried out through the S-N curve. The minimum fatigue life cycles of the closing spring and the opening spring are 2×10 ⁴ times and 2×10 ⁵ times, respectively, which meet the life requirements of the circuit breaker operating mechanism.