Backup relays are relays situated outside a designated primary protection zone, positioned in an adjoining zone. These relays are configured to activate in response to specified abnormalities occurring within the primary protection zone, operating independently of the primary relays. Serving as the secondary line of defence in the event of primary protection failure, backup relays are strategically designed to function with a deliberate time delay. This delay ensures that the primary relaying system has ample time to operate, if feasible.
