A hybrid circuit breaker consists of a series connected vacuum- and SF6(CO2) interrupter. The vacuum interrupter has the function to withstand very steep-rising transient recovery voltages, whereas the SF6(now CO2) interrupter is stressed with the peak of it.
The interaction between the two arcs has a positive effect on the interruption: Immediately before current zero, the SF6(CO2) arc assists the vacuum arc to interrupt, whereas after current zero, the vacuum arc assists the SF6 arc in the recovery against the recovery voltage.
A prototype hybrid CB for 145 kV/ 63 KA show under the test in pic.
Summary of hybrid circuit breakers benefits:
- Development in vacuum technology, particularly very high short-circuit current interrupting capability that has been obtained in bottles of reduced size.
- No environmental problem of SF6 gas by using alternative gas as CO2.
- Function at low ambient temp and a high interrupting capacity without additional capacitor.