why reverse power relay operates when we reduce the generation of a gas turbine-alternator?

 

because the generator, connected to the grid, works as a motor, and the polarized reverse power relay, senses the direction of the energy. If the energy flows from the grid to the generator,working as a sinchron motor, the relay causes the trip.

 

When alternator is running parallel with grid at rated output alternator is giving power to grid, and during load reduction we are reducing the fuel and at the point when it is difficult to maintain its normal RPM, prime mover takes power from grid to maintain its rpm, keep in view it happens only during parallel operation.

 

If the torque being produced by the prime mover is less than the amount of torque required to keep the generator rotor spinning at the speed proportional to the frequency of the grid to which the generator is connected the generator will draw current from the grid as a motor would/does in order to maintain the synchronous speed/frequency. Depending on the type of prime mover (diesel engine, steam turbine, combustion turbine, wind turbine, hydro turbine, etc.) spinning it with a motor can be very damaging to the prime mover.

Since, under these conditions, the current would be flowing into the generator instead of out of the generator the relay which monitors for the condition is called a "reverse power" relay.

 

Will there be a usage of reverse power relay between two grids of two different states????????? What happens if the power is been sent back by the reverse power employed by one state to the other state?

 

Dear all

Sorry to interrupt you but I really need a help here. At My MOPU project, there is alternator burnt. Our suspect area is reverse power. However we can't prove it is reverse power problem. May I know in what condition normally it can happen. What I understand is it can happen when synchronizing, AVR not functioning, reverse power relay not functioning etc. However I can't prove it. Can anyone please help me.

Another request which I need the answer quite critical is about the generator can become motor. I need prove that when reverse power happen, the generator will become motor and the rotation will operate the other way. Can anyone help me.

Thanks
Ezwan

 

No, the generator should not trip on the "reverse power" function - for power to ~ reverse ~ remember the said to be "reverse power" must oppose the generated power first - meaning the load to drop to zero ~ then only with too little excitation and FOWARD POWERED FORCE of the energy rotating the Rotor of the generator is NOT ADEQUATE reverse power trip function will, or should, operate BEFORE actual reverse power occurs - some reverse power protections are set too fine and operates too easy. YES the safety factor and possible danger is high ~ yet - millisecond differences in various trip logs has indicated that another protection actually trips the machine - maybe under-excitation - ?

 

why do i have a reverse power in my electric generator computer. then the generator will stop because the alarm in the computer is writing warning (reverse power)