A reverse current relay prevents a generator from discharging the battery when generator output is less than battery voltage. When generator output is greater than battery voltage, the reverse current relay closes and connects generator to electrical bus.

A reverse current relay prevents a generator from discharging the battery when generator output is less than battery voltage. When generator output is greater than battery voltage, the reverse current relay closes and connects generator to electrical bus.

The synchronous generator when act as a motor that relay is operated. or reverse power relay is acted. mainly it sence thet direction of power flow direction

A reverse power relay is a directional overcurrent relay. Directional relays are relays that sense power flow in one direction, and include (directional) overcurrent relays, reverse power, and impedance based relays.

So a reverse power relay is a directional relay, but a directional relay is not necessarily a reverse power relay.

Directional relay opeartes +/- 90degree of MTA (maxumum torque angle). Relay is set either forward or reverse depending on the direction of current flow. 180 degree to MTA is always restraint region. Some relay has chareteristic of +/- 85 degree to MTA.