Oil Circuit Breakers Are A Thing Of The Past, But Where Is The Next Stop For Vacuum Circuit Breakers? - News

news-945-510

VCB Become the mainstream switching device for medium-voltage power grids

Oil circuit breakers have largely exited the medium-voltage distribution field because of their large size, frequent maintenance requirements, and fire and explosion risks. Vacuum circuit breakers, relying on the extremely high dielectric recovery speed and diffusion capability of the vacuum medium, have become the mainstream switching devices in today's medium-voltage power grids. However, technological evolution has not stopped, and their "next stop" is extending in four directions.

Four Directions of Technological Evolution

environmentally friendly substitution. SF₆ gas has an extremely strong greenhouse effect, and many countries are gradually restricting its use. Vacuum arc interruption combined with dry air or eco-friendly gas external insulation has become an important path for greening high-voltage switchgear.

DC interruption. With the development of renewable energy DC collection and energy storage systems, demand for medium-voltage DC interruption is rising. Using commutation capacitors in coordination with vacuum switches to create current zero crossings is the main approach of hybrid DC vacuum circuit breakers.

primary-secondary integration. Deeply integrating electronic sensors and protection and metering units with the vacuum circuit breaker body can reduce equipment footprint and wiring, and improve the level of distribution automation.

digital twins and predictive maintenance. By building virtual models from state variables such as contact temperature, travel, and coil current, scheduled maintenance can be shifted to on-demand maintenance, enabling early fault warning.

The essence of 'the next station

From oil to vacuum is a dielectric revolution; from vacuum to eco-friendliness, DC capability, and intelligence is a functional revolution. The "next stop" for vacuum circuit breakers is essentially an evolution from a single interrupting device to an integrated energy control node.