[Mark VI - Gas turbine] When the turbine is running with generator breaker opened, which control is responsible for integral action? I mean, if FSRN is proportional only control, how the governor is able to get zero speed error? (isochronous control is not enabled).
We had a situation here where the generator tripped due to 49 relay, but the turbine kept running. The machine was at base load when the generator circuit breaker opened.
As expected, the speed increased when the CB opened, and the controller was able to bring the turbine back to 100%. The TNR went from 105.3% (base load) to 100% automatically when the CB opened.
We noticed that the FSR in control was the FSRN all the time (FSR_CONTROL = 6 and FSR = FSRN). The question is, how the governor managed to control FSRN to control speed exactly in 100% if the FSRN is only proportional? Which part of the governor was responsible for the integral action?
This machine operates only in droop mode. We checked the FSRNI in this event to confirm, and it was 0% all the time, that is, isochronous integral control was not on. By looking at the FSRN block (FSRNV4, Mark VI) we cannot understand how it was able to reach zero speed error, because TNR was constant, and FSRN is only proportional control.
I could send you guys any data needed, just tell me to where I should send it and what variables do you need (we have all of them available in our historical server, with really good sampling).
What we can see is FSR (and FSRN) going to FSRMIN instantaneously when the gen breaker opens, and after that FSRN is controlled until TNH reaches 100% (like it had an integral action).
I'd like to post some pictures here to help, but I don't know how.
We had a situation here where the generator tripped due to 49 relay, but the turbine kept running. The machine was at base load when the generator circuit breaker opened.
As expected, the speed increased when the CB opened, and the controller was able to bring the turbine back to 100%. The TNR went from 105.3% (base load) to 100% automatically when the CB opened.
We noticed that the FSR in control was the FSRN all the time (FSR_CONTROL = 6 and FSR = FSRN). The question is, how the governor managed to control FSRN to control speed exactly in 100% if the FSRN is only proportional? Which part of the governor was responsible for the integral action?
This machine operates only in droop mode. We checked the FSRNI in this event to confirm, and it was 0% all the time, that is, isochronous integral control was not on. By looking at the FSRN block (FSRNV4, Mark VI) we cannot understand how it was able to reach zero speed error, because TNR was constant, and FSRN is only proportional control.
I could send you guys any data needed, just tell me to where I should send it and what variables do you need (we have all of them available in our historical server, with really good sampling).
What we can see is FSR (and FSRN) going to FSRMIN instantaneously when the gen breaker opens, and after that FSRN is controlled until TNH reaches 100% (like it had an integral action).
I'd like to post some pictures here to help, but I don't know how.