hi...every body

when the machine is running at base load, if suppose there is a requirement of bringing the machine to Full speed No load condition without tripping the turbine..

Can I open the generator breaker after de-loading the machine to minimum load (like spinning reserve) or how can I get the required condition...

Kindly post your ideas....

machine is MS9001FA Gasturbine

 

sriram sandeep,

It would be done exactly as you describe. Unload the machine (manually or automatically) to some load just about zero MW, then manually open the generator breaker. There is usually a switch on the Generator Protection Panel or switchgear panel for the Generator Breaker to do this. Some--but not all--HMIs have a target on the Synch Display, or some generator-related display, to open the generator breaker.

If you gave the unit a STOP command from any load, you can interrupt/abort the automatic unloading sequence at any point by simply clicking on EITHER 'RAISE SPD/LOAD' or 'LOWER SPD/LOAD' which tells the Speedtronic that the operator wants to interrupt/abort the automatic shutdown. Or, you can continually click on 'LOWER SPD/LOAD' until you get near zero MW. Or, you can put in a very low Pre-Selected Load Control setpoint, enable Pre-Selected Load Control, and once the unit gets down to the setpoint, you can either open the generator breaker or use 'LOWER SPD/LOAD' to lower the load closer to zero MW before opening the breaker. (Some F-class units have a minimum Pre-Selected Load Control setpoint, say 15 MW or so, so it may not be possible to enter 1 or 2 MW as a setpoint.)

And, the answer for the unasked question is: No; opening the generator breaker at light load (above zero MW) will NOT harm the breaker. In fact, the breaker can be manually opened at any load with causing damage to the breaker; they are rated to be able to open under fault conditions when current in excess of generator rating may be flowing--and still continue to operate.

However, manually opening the generator breaker under "higher" load conditions is sometimes called a 'load rejection' and can result in a loss of flame trip in the turbine, especially at higher loads on a F-class turbine with DLN combustors.

And, it's not usually possible to get to automatically-controlled "Spinning Reserve" load from a loaded condition. That's usually only possible after an Auto Synchronization. And, if you use Auto Synch to re-close the breaker from FSNL (after you've manually opened it), the unit will NOT usually go to automatically-controlled "Spinning Reserve" load. So, don't be surprised if it doesn't.

Hope this helps!

 

Sriram,

try selecting "Stop" and as soon as the generator breaker opens select "Start". This should hold the unit at Full Speed No Load. If you wait too long the unit will continue to shut down.

Greg Ponto
Lead Combustion Turbine Specialist
Elwood Energy