load tunnel High temp issue TTIB on GT-9E DLN 1

GT LOAD TUNNEL TEMP TTIB DURING DECREASE LOAD BELOW 90MW IT IS GETTING HIGH ITS NEAR TO THE SET 202C POINT FOR HIGH ALARM.

the load tunnel and 88VG fan were inspected didn't found any abnormality, also checked for load and exhaust compartment gap or opening but found all to be ok, checked bearing#3 seal air line for any damage observed no issue, checked thermocouples reading all of them are similar just 1 or 2 F Degree difference.
 
WHEN DID THIS PROBLEM START? Was it after a maintenance outage? After a trip from high load?

HAS ANYONE CHECKED THE FIRE PROTECTION DAMPERS ON THE LOAD COMPARTMENT VENTS TO SEE IF THEY ARE LATCHED IN THE PROPER POSITION (OPEN) FOR NORMAL OPERATION?

The typical cause of this problem (high load compartment ("Inner Barrel") temperatures while running are fire protection dampers which have closed because the latches have worn through or broken or weren't latched properly after a maintenance outage or a fire protection extinguishing agent discharge or fire protection system test, OR there is a leak which is developing along the periphery of the load compartment where many pieces of stainless steel sheet metal form a seal in the area which is prone to movement as the unit is started, loaded and unloaded. This often happens after a maintenance outage when the metal strips are not properly installed (insufficient overlap) and not properly secured in place (bolts not tightened properly; lack of secure method to prevent bolts from loosening; broken bolts (from excessive tightening); etc.).

If all three "inner barrel" T/Cs are reading essentially the same value, then it's a safe bet that there is insufficient air flow in the inner barrel area (the "load tunnel") and that's either the result of lack of ventilation because the dampers are not fully open, OR if there was a recent maintenance outage where the load compartment vent fan(s) was(were) removed and reinstalled and the AC motor direction of rotation was not properly verified--so the fan is not running in the proper direction and developing proper air flow. There have also been reports of loose couplings between the motor and fan shafts.

BUT, this IS NOT a controls problem (presuming the T/C terminations are correct and have been verified to be correct). Use the Heating & Ventilation P&ID and the Fire Protection System P&ID to see the details of the systems in the Load Compartment. And check the seals in the load compartment. The problem is either lack of sufficient air, or leaking seals around the exhaust area.

FINALLY, there are over 20 years' worth of these kinds of questions and answers on Control.com--ALL of which are searchable and readable using the Search feature at the top of every Control.com webpage. Search and you will find and learn so much! If you have questions, you can ask here for clarification.
 
aras.ali,

I see you have Liked my initial response, and that's great!

What about answering all of the questions? You were given a fairly comprehensive list of possible causes; all you need do is provide details about what you have checked, what the results were of the checks you made, and tell us what checks you haven't made--and when you will complete them and get back to us with the results.

Easy, peasy! (Simple!)
 
GT LOAD TUNNEL TEMP TTIB DURING DECREASE LOAD BELOW 90MW IT IS GETTING HIGH ITS NEAR TO THE SET 202C POINT FOR HIGH ALARM.

the load tunnel and 88VG fan were inspected didn't found any abnormality, also checked for load and exhaust compartment gap or opening but found all to be ok, checked bearing#3 seal air line for any damage observed no issue, checked thermocouples reading all of them are similar just 1 or 2 F Degree difference.
Can you share here a quick update on the issue that you've been facing at your site....
 
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