The actual plot of GT Exhaust temp Vs Compressor Discharge Pressure shows large fluctuations at part load. The data points for the chart are extracted from data historian and filtered to have narrow GT Inlet temperature (CTIM) (in between 29 Deg C and 31 Deg C). What could be the reason for such fluctuations?

There are eight sets of TTKn_I, TTKn_C and TTKn_S. If we need to compare the actual plot of GT Exhaust temperature (median) and Compressor discharge pressure with one of these eight sets, which one should we use?

 

Murali,

We would need a lot more information to be of help with your inquiry.

First, when did this problem start?

What kind of combustion system (conventional or DLN)?

If the unit has conventional combustors, is IGV (Exhaust) Temperature Control active ("combined cycle" mode)?

At what exhaust temperature are you seeing this large variation?

What are the IGVs doing when this large fluctuation is occurring?

What is the load doing when the exhaust temperature is fluctuating largely?

If you have historical data, what is TTRX when TTXM is fluctuating? What is CSGV when TTXM is fluctuating largely? What is FSR when TTXM is fluctuating largely?

Is the "Frame 9" a 9E, or a 9FA or F-class (FA, FB, FA+, etc.)?

What fuel is being burned when this is happening?

Yes; the Exhaust Temperature control array consists of eight different sets of values. There is usually some logic to switch between the sets of values based on CPD (or CPR, depending on the combustion system).

But, you should know that at part load the exhaust temperature control is not, or should not be, active (unless IGV (Exhaust) Temperature control is active on a unit with conventional combustors).

Lastly, please put some numbers to the large fluctuations you are seeing. How low is the lowest TTXM value? How high is the highest TTXM value? What is the load at the lowest and highest TTXM values?