What happens if a fault occurs on a feeder?

• A. The recloser will open, momentarily deenergizing the line, and then close
• B. A sectionalizer will automatically energize the line
• C. The feeder automatically reverses power flow
• D. The transformer ahead of the feeder locks out

Answer: (A)

When a fault hits a feeder, the protection normally uses a recloser to quickly clear the disturbance and restore service. The recloser detects the overcurrent, opens to interrupt the fault, and then waits a short moment before attempting to close again. If the fault is temporary, the line energizes again and service is resumed. If the fault is still present, the recloser will open again and may stay open after its retries, with downstream devices like sectionalizers isolating the fault to keep the rest of the feeder energized.

Sectionalizers don’t energize the line on their own; they work with upstream reclosers to limit outage duration by isolating a faulted section after a reclosing event. A fault on the feeder does not inherently cause the feeder to reverse power flow, and the transformer ahead of the feeder doesn’t automatically lock out due to that fault—the protective actions focus on interrupting and then re-energizing the feeder as described.