FAST TRANSFER RELAY
Fast Transfer requires that the start-up source breaker be closed before the phase moves outside of Zone 1. The relay required must be able to determine the magnitude of the initial phase step change fast enough to block transfer if the phase jumps outside the phase angle limit. A time delay could also be used to determine if the phase is rapidly changing 3uch a3 the Bus II example in Figures 5 and 7. Therefore Fast Transfer requires a high speed sync-check relay that can drop out fast enough to prevent the start-up source breaker from closing on a large or rapidly moving phase angle.

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