How control the reverspower for diesel generator?

I guess you're thinking that reverse power is a generation error, but it is a change in flow direction. When two generator are running in parallel nd of sudden a generator2 prime is dropped nd due to circuit breaker2 is still in on state Gen2 draws power from Gen1 and acts as a motor. this action will damage the prime mover(engine) nd AVR too. Of course upto 10 amp of reverse current is allowed into a generator as of considering as back emf (while running as generator). So in order to stop thing reverse power, a relay is used which senses the directional flow of power nd immediately turns off the circuit breaker of off prime mover unmatched droop also develops this reverse power flow because of change in voltage nd load sharing