Theoretical analysis and system measurements confirm that high-voltage vacuum circuit-breakers can safely switch unloaded transformers. For reactor-loaded transformers, mitigation measures may be needed, similar to SF6 circuit-breakers. In transformer-limited faults, vacuum circuit-breakers excel due to their independence from fault current, making them a superior alternative to SF6 technology. Thus, vacuum circuit-breakers are suitable substitutes for SF6 in both undisturbed and fault conditions.
