A Hybrid Long-Stroke Operating Mechanism for a Fast Vacuum Circuit Breaker at Transmission Voltage

The objective of this study is to propose an optimized hybrid long-stroke operating mechanism for a fast vacuum circuit breaker at transmission voltage. The operating mechanism comprised a mono-stable permanent magnetic actuator (PMA) and an electromagnetic repulsion actuator (ERA). In the closing operation, the closing coil of the ERA is triggered to close first; the PMA is involved immediately when the metal disk of the ERA approaches half of the full stroke, and latch in the close position by permanent magnets. Here, the involvement of the PMA is triggered by a magnetic induction proximity switch. In the opening operation, both the PMA and the ERA are triggered to open at the same time. The current flowing in the PMA coil is used to counteract the electromagnetic force generated by the permanent magnets. The contacts of the vacuum interrupter separate from each other under the effect of gravity of the movable components and the electromagnetic repulsion force generated by the opening coil of the ERA. The structure of the hybrid operating mechanism is optimized by the single variable method. The introduction of the PMA into the hybrid operating mechanism could effectively complement the insufficient performance of the ERA in the case of a long driving stroke of more than 60 mm and a high movable mass of more than 20 kg. The hybrid operating mechanism would be preferred to develop 126 kV or 252 kV transmission voltage fast vacuum circuit breakers.