Dear Dhinesh,

Would you reform the question! and add more details? frankly, form myself, it is not clear.

Regards!

Azd.

Well, thanks to your response.

I reframe my question.

I have the following data’s from different  plants,

Design Guarantee NHR @50Deg ambient air condition (NHR1), Net electrical power output (NP1) @50 Deg ambient air condition, design guarantee NHR @ISO condition (NHR2), Net electric power output @ISO conditions (NP2).

In additions to the above design data, I have also the previous year site performance test measured NHR and power output which is corrected to ISO conditions. i.e. NHR3,NP3.

I could see some plants are not running to design guarantee values as they are old.

My intention is to calculate expected site NHR4 and NP4 @30Deg ambient without using individual plant correction curves as they are different model.

Accordingly, I am thinking of doing the following direct simple math…(please correct me)

First I calculate the expected site performance @50Deg ambient using the formula

NHR5=NHR1*(1+(NHR3-NHR2)/NHR2) ….. (Just correcting NHR1 with the %deviation)

Then from the two data points of performance test results i.e. NHR3 (@15Deg ambient) &NHR5(@50Deg ambient and 60%RH), I just do linear interpolation to find NHR4 (@30DegC ambient) .

Hope this may give some clarity. Please let me know if you have any questions. 

Regards

Dear Dhinesh,

The correction for gas turbine performance parameters as HR power, CDP, ….etc. to ISO or design references is used to measure the departing from the best performance. Gas turbine performance degrades due to several reasons and may be partially recovered through periodic maintenance activities or completely recovered by overhauling.

Performance parameter correction to ISO after recording the actual reading at any ambient temperature is to compare with the standard ISO condition for estimating the gas turbine healthy and measuring the deviated performance due to gas turbine degradation, hence to take the corrective acting.

You couldn’t compare different gas turbine models, as each model is compared with its own design point.

Each model has only reference condition; however some correction curves are given at multi- ambient temperature. In this case if you use such curve, you needn’t to make a correction. If you have the actual performance parameters you can compare with the data picked up from this curve as the same temperature. Only interpolation is correct in this case.

 Interpolation between the same model at different conditions (sometime new and sometime old gas turbine) isn’t correct to get the performance at another point and could lead to misleading judging. But if you need, by yourself, to make that curve and get the performance at other different ambient condition, it must be emphasized that it should be carried out for the same turbine (new or just overhauled) and at short time period (to avoid aging parameter) with fixing all the operating parameters (fuel composition, pressure and temperature, PLC set points , full driven load , inlet guide vanes , all accidently in /out masses  ,all venting and draining…..etc., and the only variable will be ambient condition to get reliable data for future comparison.

 Remember you couldn’t compare different model’s performances to get another performance point.

 You can use the following equation for power correction, if you have for example the power (ISO), at ambient temperature 15 C/59 F and ambient pressure 1.013 bar/14.7 psi . As well as, if you measure the performance at the actual temperature ,T1  (k) , and  atmospheric pressure , P1, ( bar). Then you can compare it with, power (corrected).Therefore, in this situation you just compared the actual performance corrected to ISO with the base reference datum ,i.e.,  ,to measure the turbine degradation due to for example delayed maintenance and/or overhaul , internal leaks increased tip clearance ,labyrinth damage ,partial blade failure ,fouling, ……etc. , and fellow the same procedure at different ambient temperature or for the remaining performance parameters but using the right related correction equation ,which you can find in the attached file.

   power(corrected)/ power (ISO)= ((1.013 bar)/P1(bar))x sqrt(T1/(288K))

      (use only values in  absolute )\

Thanks

Dear Mohamed Said,

First of all thank you to your time and detail writing with a needful attachment.

Please be informed that I am not trying to compare different model of gas turbine and find a single number of NHR. Instead, I would like to calculate the expected NHR and Net power output for n numbers of machines (installed in different location). I need this matrix of NHR and net power O/P for every plant to forecast the expected energy production and energy consumption. As the site performance test recent ISO values would be more conservative in terms of efficiency, I may under estimate the total energy consumption. Accordingly I am trying to correct the performance test recent data @ ISO conditions to an average temperature like 30DegC to see the expected net power generation and energy consumed as well. The intention is to do this without using individual plant machine type correction curves.

I welcome  any new ideas to do this as long as we doesn’t require all GT model correction curves and from the above specified sets of available data .

 Regards,