SGT 300. Failure Fuel Gas Control Valve Inlet

Hello everyone,

Now I have the following problem: when the power of the SGT 300 turbine is more than 7 MW, then short-term pressure surges at the inlet of the main gas fuel and pressure on the release of gas fuel. Short-term power surges of the turbine are also observed.

The amplitude of the pressure jump reaches 1 bar. (Old 18.64 bar -> New 19.8 bar -> Old 18.66 bar). Errors occur on the four primary gas sensors.
If the turbine power is less than 6.5 MW, then the short-term jump disappears.

Tell me, what could be the problem?

P.S. Trends are presented in the attach.


Best regards,
Pagle
 

Attachments

Hello Pagle ,

Would be glad to give some advices on this issue.

As i dont have the P&IDs , schematic drawings for kind of GT, Some questions are followings:


Could you tell us :


- Net Output capacity of GT
- Did you check correct operations of the differents Gas control/stop ratio valves?
- Do you get any alarms ( related or not to the gas controls valve or pressure ) from the installed controls systems ?

That would be a good thing to track the positions and feedbacks reference for such Valves , and see if they operating properly.

looking to hear back from you soon,
James
 
Hi James,

Thank you for your support.

I'll start with a list of questions:
1) Net Output capacity of GT = 7.9 MW. But usually a turbine produces a power of no more than 7.5 MW
2) I checked the correct operation of the valve. No errors or alarms occur during valve operation. I track the positions and feedbacks reference for such Valve - everything is fine.

It bothers me that short-term jumps occur only when the turbine power is more than 7 MW.

I just can’t find the documentation for this valve (TSP09355 Issue 1 CT95038 / 01 & CT95038 / 02 Integrated Fuel Valve Manual & Field Setup Procedure), it may have useful information.

Schematic drawings attached. short-term surges in PT2A, PT2B, PT181A, PT181B, TT6 sensors.
 

Attachments

Hi James,

Thank you for your support.

I'll start with a list of questions:
1) Net Output capacity of GT = 7.9 MW. But usually a turbine produces a power of no more than 7.5 MW
2) I checked the correct operation of the valve. No errors or alarms occur during valve operation. I track the positions and feedbacks reference for such Valve - everything is fine.

It bothers me that short-term jumps occur only when the turbine power is more than 7 MW.

I just can’t find the documentation for this valve (TSP09355 Issue 1 CT95038 / 01 & CT95038 / 02 Integrated Fuel Valve Manual & Field Setup Procedure), it may have useful information.

Schematic drawings attached. short-term surges in PT2A, PT2B, PT181A, PT181B, TT6 sensors.
Hi Pagle,

Thanks for sharing with us these informations.

It would be nice to get an overall picture of the gas valve arrangement at your plant.

Well The pressure / temperature surge occur as you mentionned at 7 MW wich is not far from Unit max output.

Generally there is a stop ratio valve , wich is used for maintaining constante pressure at interstage ( Called P2 Presure).
I dont know if you have facing some surge at this point or any malfunction at the moment .
At this moment you mentionned that tracking is ok for Main control valve but did it works properly for the Stop ratio valve?
Do you know the tolerance +/- for such pressure/temp ??



Also you mentionned documentation for valve but from wich OEM manufacturer ??


Maybe Somebody on the forum can share his knowledge for such situation...

Will try to get some support for this issue

Cheers,
James
 
Hi Pagle

Try to have a look on this thread it can help also on the forum there are some interestings posts on the subject:

https://specialties.bayt.com/fr/specialties/q/116804/in-gas-turbine-what-is-relation-between-srv-and-p2-pressure/

James,
I will try to read with the stop ratio valve.
Unfortunately, I do not know tolerance +/- for such pressure / temp yet. I will consider this information.

OEM manufacturer of integrated fuel gate valves - Siemens. I requested this document from them. But so far they have not given an answer.

Thank you for the thread. I will study the information.

James thank you very much for your advice, you inspire me with hope!

Best regards,
Pagle
 
James,
I will try to read with the stop ratio valve.
Unfortunately, I do not know tolerance +/- for such pressure / temp yet. I will consider this information.

OEM manufacturer of integrated fuel gate valves - Siemens. I requested this document from them. But so far they have not given an answer.

Thank you for the thread. I will study the information.

James thank you very much for your advice, you inspire me with hope!

Best regards,
Pagle


Hi Pagle,

Thank you for you rlast message i appreciate it.

I would suggest you to read this important thread it can be a help:
https://control.com/forums/threads/inter-valve-pressure-in-gas-turbine.42056/
Kind regards,
James
 
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