Reverse Power Relay

This relay is used in generators and becomes a very important parameter when parralleling generators. Imagine you are trying to "bring in" a generator in sync to a generator already caterng to load, and due to some reason the incoming generator has lesser speed than the loaded generator then reverse power will flow and the incoming generator will start motoring. This condition is picked up by reverse power relay and it trips the incoming generator thus saving it from damage. To give an analogy........ Consider a cart pulled by Horse A and all is fine...and if a yoke is placed and Horse B is (a slow lazy horse) asked to share the load then Horse A will have to take all the load and will actually cause the cart to go in reverse direction, since Horse A is connected to Horse B with yoke. ( Horses have to be in same speed to maintain the direction ) This condition will exist till the Horse B is removed from load sharing.... This can happen when the two generators are already synchronised and one of them runs out of fuel thereby the speed drops and reverse power flows into it, again reverse power relay will be the protector. I will not give the horse analogy for this situation and will leave it to your imagination.. Good luck

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Good luck,

James