when given shut down or stop command during loading reducing, gas turbine is tripping near 20 MW before normal shut down. turbine is frame 7 hitachi made and GE mark v control. pls give sport and alarm is coming SRV position trouble

 

i presume you should check the command that is being issued to the SRV and the actual position of the SRV. maybe the SRV is unable to go to the full close position due to mechanical fouling. or maybe the SRV is actually closing but the position transmitter is not working over the full range.

 

Did you check you SRV LVDT feedbacks?? the mismatch between the two LVDTs??

 

Alarms don't mean anything, until the turbine trips. Everyone knows that. Especially Diagnostic Alarms. And, then it's the last trip alarm that's the one that caused the turbine to trip; everyone knows that, too. (NOT.)

But, I digress.

If you want to understand what is causing the turbine to trip, you are going to have to have a look at the Trip History (Trip Log) display, and determine what alarm message is being annunciated at the time of the trip (and, likely what messages were annunciated prior to the trip).

Then you need to use the Alarm List to cross-reference the Drop Number to the logic signal that's set to a "1" at the time of the trip, then use Dynamic Rung Display or the CSP Printout (and CSP Cross-Reference) to determine what is causing the trip.

There's little we can do to help you at this point. You have provided almost zero useful information, including what the gas fuel supply pressure is doing prior to the trip, what the P2 pressure is doing prior to the trip, what Process- and Diagnostic Alarms are present prior to the trip, and for how long some of them might have been present, and when this problem started (such as after a maintenance outage, or an LVDT "calibration", or after the SRV was refurbished, etc.). We don't know if the unit has conventional combustors, or DLN combustors, or if it has Wet Low NOx injection (water or steam) or anything about it--because we're not there, and you didn't tell us anything except it's a GE-design heavy duty gas turbine, packaged by Hitachi, and equipped with a Speedtronic Mark V!

<b>AND</b> it's very possibly, nay likely, that the SRV Position Trouble Alarm (trip) is being annunciated <b>after</b> the actual turbine trip. (GE has this annoying habit of preventing trips from being annunciated after a turbine has been tripped, making the determination of the actual cause of the turbine trip very difficult. Many people mistakenly believe the last trip annunciated is <b>the</b> trip, and that's not true. The <b>first</b> trip message annunciated is the cause of the trip, and any subsequent trips are simply the result of GE's poor practice of not blocking subsequent trips.

So, have a look at your Alarm Printout (I have USD$1000.00 that says the printer isn't working or turned on at your site....) or, if that won't do have a look at the Alarm History in the Trip History (Trip Log). Remember, you need to print the Trip History (Trip Log) <b>IMMEDIATELY AFTER</b> the trip event, and <b>BEFORE</b> you initiate a Master Reset or any other action. Otherwise you may (likely will) lose the information you require.

The Trip History (Trip Log) capture buffer is triggered every time L4 transitions from a logic "1" to a logic "0". So, get the Trip History (Trip Log) immediately after a trip and before you do anything else other than Silence the audible alarm horn. (And, another of my USD$1000.00 says the alarm horn is not working at your site, as well....).