Where is a VCB preferred over oil/SF₆ breakers?

A Vacuum Circuit Breaker (VCB) is the dominant technology in medium-voltage (MV) applications (typically 3.3kV to 36kV). It is highly preferred over older Oil Circuit Breakers and is now also a major competitor to SF₆ breakers in this range.

VCBs are preferred in the following applications:

• Indoor and Underground Substations: VCBs are compact and, most importantly, have no risk of fire or gas leakage. Oil breakers carry a significant fire hazard, and SF₆ is a potent greenhouse gas that is dangerous if inhaled after arcing. The safety and environmental friendliness of a VCB make it ideal for enclosed spaces.
• Applications with Frequent Switching: VCBs have an exceptionally long operational life and can perform a high number of switching operations with minimal maintenance. This makes them perfect for demanding applications like arc furnaces, railway traction systems, and capacitor bank switching.
• Environmentally Sensitive Projects: With growing global concern over greenhouse gases, VCBs are preferred over SF₆ breakers. SF₆ is the most potent greenhouse gas known (over 23,000 times worse than CO₂), and regulations are becoming stricter on its use and handling. VCBs contain no gas and are therefore the environmentally superior choice.
• Rural and Remote Distribution: Their high reliability and low maintenance requirements make them an excellent choice for remote substations where frequent service is impractical.