What is the purpose of a reclosing scheme in transmission protection?

• A. To automatically reclose after a fault clears, enabling quick restoration of service if the line is healthy.
• B. To provide continuous monitoring of line loads for optimal efficiency.
• C. To delay tripping to reduce wear on breakers.
• D. To manually secure the line during maintenance.

Answer: (A)

A reclosing scheme is designed to automatically reclose a transmission line after a fault has cleared, so service can be restored quickly if the line is healthy. When a fault occurs, protective relays trip the line to clear the fault. After a short dead time, the reclosing controller sends a signal to close the breakers again. If the fault was temporary (a lightning strike, a momentary contact, etc.), the line re-energizes and power is restored without manual intervention. If the fault persists, subsequent reclosing attempts fail and the line remains de-energized, allowing maintenance or fault clearance before the circuit is brought back in service.

This approach improves reliability by reducing outage duration for transient faults, while still protecting equipment from sustained faults. It’s not about continuously monitoring line loads, and it isn’t simply to delay tripping or for manual operations during maintenance.