GE Frame 5 limited below Rated Power


Thread Starter


I will be trying to troubleshoot a Frame 5 power problem shortly and wanted to know if any of you out there have experience this kind of problem before.

The Turbine Control System was retrofitted from a Mark IV to a Mark V. The turbine ran at rated power prior to retrofit. I don't have all the details yet.

My background is GE Steam Turbine Controls. I'm trying to get my feet wet with the Frame Gas Turbines and need help from you guys out there.

Your help is appreciated. Thank you.
Dear Colladjl, as you are well aware the more information you provide, the better information this forum can provide.

Rated power for a gas turbine is typically stated at "ISO conditions", for most Frame 5 units base load is usually around 25MW depending on ambient temperatures mostly. The real question is what power was the unit able to produce before the controls change, you say "The turbine ran at rated power prior to retrofit.", was that 25MW or what? How much less is it able to produce now, and are the conditions IE fuel type, temperature, humidity, inlet pressure drop etc. all the same.

The first thing I would compare would be all of the control constants from the MKIV to the MKV. Assuming the sequencing logic was replicated properly the next item that could cause this type of problem would be control constants that do not match, especially ones for firing temperatures etc. The next area I would check would be instrumentation, most importantly CPD transmitters, exhaust thermocouples, fuel gas valve calibrations, and IGV calibration.

Once you arrive onsite you can rule out some of these items fairly quickly, the main thing is to verify the complaint and identify what is "limiting output". On your next post you might include more information about fuel types used on this turbine, any water or steam injection, any inlet cooling, and lastly if it uses modulated or 2 position IGV's.

Hopefully this gives you some rough starting information, now its up to you , good luck.
With miniscule details, it is very difficult to comment. Provide more details for a to-the-point reply, but prima-facie it seems that there would be changes with some critical constants resulting in lower output considering that there was only a control retrofit which ideally should not by itself lower the unit output.

Pl. provide details

Juan Collado


Thanks for your detailed response. Once, I get to the site I will have more information to post. Again, thanks.

*Are you Mike Henderson by any chance?

To throw some light, I understand that the constants could have been possibly fiddled particularly - speed control droop reference value(%/MW). Check all values pertaining to primary and secondary curves (TTkn_I, TTkn_m, TTkn_k, TTkn_S & TTkn_C). check for associating constants to CSRGVTXB & L60GVTC. Hope you get some help. pen back your findings.