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Dear All,
Would like to share our recent experience and hope can get some advice/feedback from other users here.
Our unit is 9FA single-shaft combined cycle gas turbine, utilizing DLN 2.0+ combustion system. Type of control system is Mark V TMR, with HMI.
We encountered 2 incidents of unit trip due to High Exhaust Temperature Spread when deloading for overnight shutdown, during change-over firing mode from Premix to Piloted Premix.
From the trip log, prior to tripping, exhaust thermocouples #28 - #31 and #1 - #6 detected much lower temperature. From the SOE, no abnormality is observed for the GCVs. Only Flame Detector Trouble alarm and Combustion Trouble Alarm activated prior to High Exhaust Temperature Spread.
Problem occurs intermittently since 9th Oct 2012 and not every unit shutdown has got this problem, probably I can say 50% / 50%. Has anyone experienced similar problem before?
Would like to share our recent experience and hope can get some advice/feedback from other users here.
Our unit is 9FA single-shaft combined cycle gas turbine, utilizing DLN 2.0+ combustion system. Type of control system is Mark V TMR, with HMI.
We encountered 2 incidents of unit trip due to High Exhaust Temperature Spread when deloading for overnight shutdown, during change-over firing mode from Premix to Piloted Premix.
From the trip log, prior to tripping, exhaust thermocouples #28 - #31 and #1 - #6 detected much lower temperature. From the SOE, no abnormality is observed for the GCVs. Only Flame Detector Trouble alarm and Combustion Trouble Alarm activated prior to High Exhaust Temperature Spread.
Problem occurs intermittently since 9th Oct 2012 and not every unit shutdown has got this problem, probably I can say 50% / 50%. Has anyone experienced similar problem before?