Study on Effect of Spring Fatigue on Mechanical Characteristics of High Voltage SF6 Circuit Breaker

Abstract

The mechanical characteristics are of great significance for the interruption performance of high voltage circuit breaker. In this paper, the 126 kV high-voltage SF6 circuit breaker with spring operating mechanism is taken as the study object. The fatigue curve of the opening and closing spring is measured by the experiment and, on the basis of analyzing the fatigue mechanism of the spring and the theory model of the relaxation process of spring stress,the linear regression equation for predicting spring fatigue is set up. The multi-body dynamics model of the spring operating mechanism of high-voltage circuit breaker is set up and the dynamic simulation is carried out in accordance with actual operation condition of the circuit breaker so that the mechanical characteristic of circuit breaker is calculated and analyzed. On this basis, the variation characteristic of the opening/closing stroke and speed with time at different years of operation are analyzed, the performance degradation law of circuit breaker with different fatigue conditions is revealed and mechanical state predication of high-voltage circuit breaker within the whole life cycle is achieved.