Recent content by jeff3300

Great info here, thanks. one question though, it was mentioned above that selecting “pre-select load” wouldn’t interfere with the machine’s droop response to grid frequency disturbances. Why is that? I assumed that pre-select load would be looking at DWATT and trying to maintain a specific...

I just came across this old thread while surfing today and remembered a little piece of info that I forgot to add at the time- If you read my original post I mentioned that when the IBH valve positioner failed initially it went wide open for a moment and then closed... what we learned after the...

One thing to consider when changing steam conditions at the turbine inlet is the wilson line curve- at high rates with cool steam you may risk early condensation and blade erosion in the LP section of the turbine.

I think in this context SRV refers to "Speed Ratio Valve", and its purpose it to maintain steady gas pressure (P2 pressure) upstream of the control valves to facilitate turbine speed control.

This may not be most appropriate place to ask, but is anyone aware of how the addition of fault current limiters upstream of the step-up 34.5/138kVA utility transformers leaving a generating plant might effect power factor? Is it negligible?

Hi, The unit is roughly 20 years old with DLN combustors. The CPD lines run outside the enclosure and the transmitters are located near the exhaust frame blowers

I'm guessing you need to replace the positioner or set limits on a new one? We've done that in the past with the unit running, we lost a few MW of generation when VA20 was open but it didn't cause any issues operationally. Cheers

Thanks for the reply- you're right about the forcing removing DWATT 1 from the loop, as MIKEVI mentioned above there is a high select block in there that chooses which transducer controls the machine. I'm still trying to wrap my head around why a malfunction with the nexus meter ran the machine...

Can you provide any more detail on how the signal from the nexus meter relates to the control of the unit? Is it just generator load control or is it part of the excitation loop as well? Also, is this something that would vary between sites or is it generally the same between units?

Hi guys, Thanks for the reply. The nexus meter is connected to the generator PT and CT- which is why I've been told we cannot replace it while the unit is running. We do have an alarm in G1.LDWATT_ALM "megawatt transducer signal trouble" and an alarm for "signal forcing enabled" which I assume...

Hi Mike, You are correct, the ignitor assembly was initially replaced and misaligned on a hot gas outage- the annoying thing was the machine was able to crank and fire just fine when coming up from a stop so we never realized there was a problem until much later when coming down for some...

Ended up replacing the IBH valve feedback positioner, that sorted out all of our problems. Stroking the valve to calibrate the new positioner swung the machine around a little, but nothing too surprising. The mark VIe required a 'master reset' to clear the IBH trip alarm that came in when it...