Generation Question
Generation Question
(OP)
Could someone please explain the difference between 'Isochronous mode' and 'droop mode' when talking about two diesel generators connected in parallel on it's own common bus and not connected to a utility. Which method would be the best way to run these.
many thanks
many thanks






RE: Generation Question
RE: Generation Question
Droop mode means that the generator speed decreases a little with load. This allows generator load control when the generator is running in parallel with the grid or in parallel with other generators but isolated from the grid. It allows for stable parallel operation.
When you have two (or more) generators connected in parallel with each other, but isolated from the grid you can have one in isochronous mode and the other(s) in droop mode. The generator(s) that are in droop mode will operate at the same frequency as the generator that is in isochronous mode. The generator(s) in droop mode will be at constant load whilst the generator in isochronous mode will be the "swing" machine and its load will move up and down as required to ensure that the generatod power matches the load demand.
Refer to the Woodward website for lots of good information on governors and control of generating plant.
http://www.woodward.com
Regards
RE: Generation Question
http://www.tpub.com/celec/66.htm
http://www.tpub.com/celec/64.htm
etc. for more info
RE: Generation Question
Would it be possible for two or more generators to be run in Isochronous mode or would you you only have one of them in this mode.
thanks
RE: Generation Question
You can have two or more generators running in a sort of isochronous mode, but to do this you need to have an overall controller for each generator "above" the governor. With Woodward equipment, that would mean using an EGCP2 for each generator. One EGCP2 ends up being a master unit and trims all the other generators via their EGCP2 controllers. The trimming is done via serial link between all of the EGCP2's. This system only works when the generators are running in parallel with each other but isolated from the grid. EGCP2's are fairly expensive.
If you did not have such a system, I think it would not really be possible to operate two or more generators in isochronous mode. To do so they would need to be identical machines, have identical responses and all the governors would need to have identical control settings. Not practically achievable I think.