The Quality and Parameters of Bellows Affecting the Mechanical Endurance of Vacuum Interrupters

With global warming, electric power equipment with SF6-free insulation technology is being developed. As one of the solutions, vacuum interrupters (VIs) with higher mechanical reliability are needed. The bellows is a key component that affects the mechanical endurance performance of VI. In this paper, fatigue cracks in bellows caused by manufacturing defects have been investigated. Mechanical endurance can be improved by adding 1 or 2 convolutions and increasing the diameter. The impact of the circuit breakers (VCB) mechanical parameters has been calculated. By eliminating the bellows defect, adding one more convolution to the bellows, and optimizing the mechanical characteristics of the VCB, the mechanical endurance performance of a 24kV VI has increased from 18,000 to more than 30,000 cycles.