Gas Turbine Power Output

S

Thread Starter

suryapower

Dear Sir,

Our facility consist 1 Power block. The power block consists of 2 GAs turbines frame 9Fa dln 2.0+ and gas turbine GE D11.

Around 1 year back gas turbine HGPI and Package 4 upgradation (R0 and R11 blades of compressor changed to improve the reliability of gas turbine).

when both gas turbines are in AGC (automatic Generation control, i.e load set point by grid operator) both are sharing the load equally lets say grid operator given 600 mw then its like both GT's at 190 MW and ST at 220MW.

Now the concern is when both gas turbines are at part load...lets say GT A is operating at high efficiency of around 0.8 to 0.9% in combined cycle when compared to GT B.

I was completely confused why its happening this way...i checked almost all parameters..for me the thing which is triggering i feel is IGV angle...IGV angle requirement for the same gas turbine output is different for both turbines...

say for turbine GT A for load setpoint 190 MW its around 75 deg. turbine GT B for the same load setpoint 190 MW its around 70 deg. FSR setpoint is almost same for both units and it is in speed control. around 0.5 kg/sec fuel flow difference is observed.

So at part load GT A is operating efficiently when compared to GT B.

However the main concern is when both machines are kept at base load.. GT B is giving more output around 7 MW more compared to GT A (the one operating efficiently at part load).

Note: before upgrade the difference is only around 2 MW and after upgrade also around 2 to 3 MW. but past 6 months only it has been observed the output difference increased almost to 7 MW.

what could be the possible reasons? how to start troubleshooting? i was failed to understand CSGRV (inlet guide vane reference block how it is calculating too).

your kind cooperating is highly appreciated.
 
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