In a ring bus switchyard, a fault on the bus will result in the entire system being de-energized.

• A. True
• B. False
• C. Depends on configuration
• D. Not enough information

Answer: (B)

A ring bus is built to keep power flowing even if a fault appears on the bus by isolating only the faulty section. When a bus fault occurs, the protection scheme trips the breakers around the fault and opens that section, while the rest of the ring remains energized because an alternate path around the ring still carries current. Therefore, a fault on the bus does not inherently de-energize the entire system. The exact outcome can depend on how the protection is set up and the specific configuration, but with proper coordination, only the faulted section is taken out of service and the rest stays energized.