IBH Trip

Dears,

Our GT stopped on the following signals, could you please advice us how we can solve this problem? \some time it trip on ( IBH valve not following trip ) and other times it trip on ( IBH control valve trip solenoid valve)

Thank you and I’m waiting for your reply.
 
Hi Smallengineer,

Would you plz tell us :

GT Frame
Control system associated..
Operating Load when event occured..

For first impression it would be a good idea to check IBH valve operating mode correctly ( operating position to check )

With more datas we can be better support here...

Cheers
James
 
Small_an_Engineer,

As ControlsGuy25 says, we need to know more about the machine you are working on.

MOST of the GE-design heavy duty gas turbines I have had the pleasure to work on have had air-operated (pneumatic) actuators. Based on the information you provided, it would appear there is something not correct with the actuator.

There is a P&ID drawing of the IBH system you should be using to understand and troubleshoot the system. Most of the IBH systems have quick-exhausting valves to allow for the IBH control valve to quickly return to it's default position in the event of any trip while the turbine is running.

Clean, dry air from an instrument air system is CRITICAL to proper operation and longevity of the IBH system!!! I cannot stress that enough. Moisture in the air and incorrect air pressure are the most common problems.

There is usually an air pressure regulator supplied with the IBH system. They require regular maintenance and operational checks and adjustments if necessary.

To be any more precise, we need the information requested. We also need to know what control system is being used, and if you have any alarm printouts from pre- and post trip.
 
Hi Smallengineer,

Would you plz tell us :

GT Frame
Control system associated..
Operating Load when event occured..

For first impression it would be a good idea to check IBH valve operating mode correctly ( operating position to check )

With more datas we can be better support here...

Cheers
James
Dear sir,

Thank you for your reply. The information you asked me for is as follows:

GT Frame: GT MS5001PA DLN AND ELECTRIC GENERATOR

Control system associated: Mark Vie

Operating Load when event occurred: 7 MW

(Please, note 27 MW is the total MW that can be generated)

Best regards,
 
Small_an_Engineer,

As ControlsGuy25 says, we need to know more about the machine you are working on.

MOST of the GE-design heavy duty gas turbines I have had the pleasure to work on have had air-operated (pneumatic) actuators. Based on the information you provided, it would appear there is something not correct with the actuator.

There is a P&ID drawing of the IBH system you should be using to understand and troubleshoot the system. Most of the IBH systems have quick-exhausting valves to allow for the IBH control valve to quickly return to it's default position in the event of any trip while the turbine is running.

Clean, dry air from an instrument air system is CRITICAL to proper operation and longevity of the IBH system!!! I cannot stress that enough. Moisture in the air and incorrect air pressure are the most common problems.

There is usually an air pressure regulator supplied with the IBH system. They require regular maintenance and operational checks and adjustments if necessary.

To be any more precise, we need the information requested. We also need to know what control system is being used, and if you have any alarm printouts from pre- and post trip.
Dear sir,

Thank you for your help.
I am sending the information required above and I'd like to tell you that we have tested the operation of the IBH valve by sending a certain opening value to the IBH from the PLC and watched it on the site , and found it working well. Please send me your comment or notes.

Best regards.
 
Sir,

Without being able to see the EXACT application code (programming) running in the Mark VIe at YOUR site, we can only make recommendations. If we could also see the P&ID for the IBH System we might have more recommendations, also.

USUALLY, when there is a problem with the IBH not following the reference it means the IBH has been commanded to move to a certain position but it is not moving or is moving slower than should be expected. This can be confirmed by reviewing the application code runnng in the Mark VIe.

As previously written, MANY problems with pneumatic control valves are related to moisture (water) in the air supply, and if there is an air pressure regulator at the IBH location it could be the air pressure regulator might not be working properly and/or is not adjusted properly.

If the IBH control valve is not moving or is moving sluggishly when the turbine is running it is very possible the actuator is binding because of misalignment or moisture in the actuator (usually a single- or double-acting piston). We have no way of knowing if the installation of the equipment is done per the manufacturer's recommendations or if it has been maintained properly, or if it was recently removed and reinstalled as part of a maintenance outage or some issue with the valve or system.

It's NOT very likely the problem is the result of some issue with the Mark VIe. It is a digital control system, and usually there are Diagnostic Alarms (which are most commonly and very regularly ignored at most sites....) to alert conscious operators and technicians to problems with the Mark VIe system.

Based on the information provided, that's all we can say at this time. It is possible to attach photographs and .pdf files to threads in Control.com. We have offered about as much as we can based on the information provided. If you require more assistance, you are going to need to provide more information--alarm printouts, trend information (the Mark VIe has an excellent Trend recorder which can be used to gather operating information (reference position; position feedback; commands; status; etc.)), photographs of the installation and condition of the equipment, .pdf files of the IBH P&ID, etc. But, without more detailed information this is the most we can provide based on the information provided.

Hope this helps!
 
Dear sir,

Thank you for your reply. The information you asked me for is as follows:

GT Frame: GT MS5001PA DLN AND ELECTRIC GENERATOR

Control system associated: Mark Vie

Operating Load when event occurred: 7 MW

(Please, note 27 MW is the total MW that can be generated)

Best regards,
Hi


As CSA said it would be nice to get some signals trends on another shot for this unit...

Do you see both alarms & Trips or there is only Trip for IBH not tracking/following...

It would also good to see what is configured in the app code..and see if it all ok..


When this problem occured...any work have been done around this equipment ...

Cheers,
James
 
Is there any kind of IBH "auto" test function implemented on this unit?

If so did you perform it and right down /checked IBH parameters/signals as per Application code..

I advise you to do that...
 
Is there any kind of IBH "auto" test function implemented on this unit?

If so did you perform it and right down /checked IBH parameters/signals as per Application code..

I advise you to do that...
Is there any kind of IBH "auto" test function implemented on this unit?

L20TH1X Inlet heating control valve trip sol valve supplies air the IBH Valve. Some sort of valve positioner and feedback is also on the valve.

Force L20TH1X and L14HS while the turbine is offline for your function test.
 
Is there any kind of IBH "auto" test function implemented on this unit?

L20TH1X Inlet heating control valve trip sol valve supplies air the IBH Valve. Some sort of valve positioner and feedback is also on the valve.

Force L20TH1X and L14HS while the turbine is offline for your function test.
Ok thanks for these inputs...
@Curious_One

Also i advise @Small_an_Engineer to check parameters related to this IBH like there shown in Mark6e APP CODE...
There are some points that can be verified for smooth operation of the control valve...again look carefully on the app code that is installed on this unit..

Looking to hear from you soon,

Cheers
James
 
Sir,

Without being able to see the EXACT application code (programming) running in the Mark VIe at YOUR site, we can only make recommendations. If we could also see the P&ID for the IBH System we might have more recommendations, also.

USUALLY, when there is a problem with the IBH not following the reference it means the IBH has been commanded to move to a certain position but it is not moving or is moving slower than should be expected. This can be confirmed by reviewing the application code runnng in the Mark VIe.

As previously written, MANY problems with pneumatic control valves are related to moisture (water) in the air supply, and if there is an air pressure regulator at the IBH location it could be the air pressure regulator might not be working properly and/or is not adjusted properly.

If the IBH control valve is not moving or is moving sluggishly when the turbine is running it is very possible the actuator is binding because of misalignment or moisture in the actuator (usually a single- or double-acting piston). We have no way of knowing if the installation of the equipment is done per the manufacturer's recommendations or if it has been maintained properly, or if it was recently removed and reinstalled as part of a maintenance outage or some issue with the valve or system.

It's NOT very likely the problem is the result of some issue with the Mark VIe. It is a digital control system, and usually there are Diagnostic Alarms (which are most commonly and very regularly ignored at most sites....) to alert conscious operators and technicians to problems with the Mark VIe system.

Based on the information provided, that's all we can say at this time. It is possible to attach photographs and .pdf files to threads in Control.com. We have offered about as much as we can based on the information provided. If you require more assistance, you are going to need to provide more information--alarm printouts, trend information (the Mark VIe has an excellent Trend recorder which can be used to gather operating information (reference position; position feedback; commands; status; etc.)), photographs of the installation and condition of the equipment, .pdf files of the IBH P&ID, etc. But, without more detailed information this is the most we can provide based on the information provided.

Hope this helps!

Dear sir,

As you say there is usually a problem of IBH when it commanded to move to a certain position but it does not move for certain time. So, what will happen if we make the controller to keep the IBH valve full open at all the time ? So, it will not move to any position. Do you think this will help?
 
Is there any kind of IBH "auto" test function implemented on this unit?

L20TH1X Inlet heating control valve trip sol valve supplies air the IBH Valve. Some sort of valve positioner and feedback is also on the valve.

Force L20TH1X and L14HS while the turbine is offline for your function test.
Dear sir,

If we force the Sol valve to make the IBH full open and do not move to any other position while running, Do you think this will help ?
 
Ok thanks for these inputs...
@Curious_One

Also i advise @Small_an_Engineer to check parameters related to this IBH like there shown in Mark6e APP CODE...
There are some points that can be verified for smooth operation of the control valve...again look carefully on the app code that is installed on this unit..

Looking to hear from you soon,

Cheers
James
Dear sir,

We are thinking to make the IBH valve does not change it position while the unit is running. (Do not use the function of IBH). Do you think it is right ?
 
Hi All,

Tryin to solve an issue without eliminating "root cause " of the issue is not well recommanded..

Forcing signals should be reserved to commissioning/maintenance work not on a normal operation of any unit ...
 
Dear Sir,

Did you ever think about why and how this happened ..

We suggested some points to follow /achieve and then coming back here for better troubleshooting, but you seems to just want that unit operating without knowing cause of the incident...
Which is for us "not a good choice boss"...

Just try to chase the cat by checking the installed app code..and try to know what is going wrong ever if it is mechanical /controls sytems problem..that's the best advise that i can give you

You asking if forcing any signals or blocking movement of any valve like you stated here:
" We are thinking to make the IBH valve does not change it position while the unit is running. "

I just can answer that why you think OEM installed that IBH ( because it have it proper function ) so you may risk the unit to surge event for example like some sites experienced ...

Any time!
James
 
Dear Sir,

Did you ever think about why and how this happened ..

We suggested some points to follow /achieve and then coming back here for better troubleshooting, but you seems to just want that unit operating without knowing cause of the incident...
Which is for us "not a good choice boss"...

Just try to chase the cat by checking the installed app code..and try to know what is going wrong ever if it is mechanical /controls sytems problem..that's the best advise that i can give you

You asking if forcing any signals or blocking movement of any valve like you stated here:
" We are thinking to make the IBH valve does not change it position while the unit is running. "

I just can answer that why you think OEM installed that IBH ( because it have it proper function ) so you may risk the unit to surge event for example like some sites experienced ...

Any time!
James
Thank you very much. I completely agree with you and that I'll certainly tell whom it may concern to be on the save side.

Best regards,
 
The concept of IBH has been written about extensively before in several threads on Control.com. One of the great things about Control.com is that prior threads can be read by using the ’Search’ feature at the top of every Control.com webpage.

If you want to understand what IBH does (which you should no matter what) you should read some of the many prior threads about IBH before deciding to just leave the IBH control valve wide open all the time. You will not be able to reach full load, for one. For another, it’s very possible serious damage to the axial compressor may occur. For still another it’s very likely the NOx emissions will be out of compliance and combustion system damage may occur.

If anything, you should be considering just disabling IBH by forcing it off, but that will change the loads at which the combustion mode changes will occur which may affect the operation of your plant.

If the IBH control valve operates fine when the unit is not running (which I believe you have said) but it doesn’t move properly when the unit is running then something is wrong. We have suggested several possibilities but you haven’t provided ANY feedback about the results of checking the components. I can pretty much guarantee that the control system is not the problem—even though it’s always the main suspect for problems like this. If the control system is telling the valve to move but the valve is not moving there is something wrong with the valve or the actuator or the way the valve/piping is aligned or supported. It’s not that complicated, as you will eventually find after some damage has occurred by operating the turbine with the IBH control valve forced open all the time. Because there will be lots of time during the repairs to the unit to properly examine the valve and actuator and it will be quickly apparent just how simple the valve and actuator are. They are very simple pieces of equipment that serve a very important and complicated function.

I can assure you that failing to fix this valve and/or actuator is going to cause much more trouble than anticipated and that means the unit will be out of operation for some time and at a great cost and loss of revenue by forcing the valve to remain open at all times. But, it’s not my equipment and not my choice. You did ask our opinion, though.

Fix the valve and/or actuator now, or you’ll have plenty of time to fix it later while you’re fixing other damage if you force it to remain open all the time. The damage may not happen right away, but it will happen and it will be costly—much more costly than shutting the unit down now to find and fix the problem.

Finally, if the unit is tripping because it is being operated with a faulty IBH control valve the tripping is contributing to a weakening of turbine parts that may also cause serious damage at some point—maybe not right away but the cumulative effect will not be pretty. Fix the valve/actuator.

You and everyone at your plant will be happy it was fixed.

Force it to remain open at all times and there are going to be some very unhappy people at your plant.

And, read some of the past threads about IBH to understand what it does and why it’s important. I realize NOx emissions aren’t important in some parts of the world, but if a unit has a DLN combustion system and IBH it needs to be maintained and operated properly for longevity and revenue generation. Or it’s not going to be worth much when it’s a pile of scraps. And people are going to be looking for new jobs.

Fix the damn valve/actuator instead of looking for a dangerous workaround.

Consider this a ‘duty to warn’ that if you don’t fix the damn valve/actuator unit damage is going to happen and it might even result in injury or death to personnel. It’s very simple equipment that performs a very important AND protective function. That’s why the control system trips the unit when it doesn’t move properly!!!

Blessed day.
 
By the way, I would gladly admit I was wrong if you wrote back to say the control system was actually the problem after working on the valve/actuator, but based on the information provided I’m pretty confident that’s not going to happen (that the control system is found to be the problem).

Again, blessed day.
 
The concept of IBH has been written about extensively before in several threads on Control.com. One of the great things about Control.com is that prior threads can be read by using the ’Search’ feature at the top of every Control.com webpage.

If you want to understand what IBH does (which you should no matter what) you should read some of the many prior threads about IBH before deciding to just leave the IBH control valve wide open all the time. You will not be able to reach full load, for one. For another, it’s very possible serious damage to the axial compressor may occur. For still another it’s very likely the NOx emissions will be out of compliance and combustion system damage may occur.

If anything, you should be considering just disabling IBH by forcing it off, but that will change the loads at which the combustion mode changes will occur which may affect the operation of your plant.

If the IBH control valve operates fine when the unit is not running (which I believe you have said) but it doesn’t move properly when the unit is running then something is wrong. We have suggested several possibilities but you haven’t provided ANY feedback about the results of checking the components. I can pretty much guarantee that the control system is not the problem—even though it’s always the main suspect for problems like this. If the control system is telling the valve to move but the valve is not moving there is something wrong with the valve or the actuator or the way the valve/piping is aligned or supported. It’s not that complicated, as you will eventually find after some damage has occurred by operating the turbine with the IBH control valve forced open all the time. Because there will be lots of time during the repairs to the unit to properly examine the valve and actuator and it will be quickly apparent just how simple the valve and actuator are. They are very simple pieces of equipment that serve a very important and complicated function.

I can assure you that failing to fix this valve and/or actuator is going to cause much more trouble than anticipated and that means the unit will be out of operation for some time and at a great cost and loss of revenue by forcing the valve to remain open at all times. But, it’s not my equipment and not my choice. You did ask our opinion, though.

Fix the valve and/or actuator now, or you’ll have plenty of time to fix it later while you’re fixing other damage if you force it to remain open all the time. The damage may not happen right away, but it will happen and it will be costly—much more costly than shutting the unit down now to find and fix the problem.

Finally, if the unit is tripping because it is being operated with a faulty IBH control valve the tripping is contributing to a weakening of turbine parts that may also cause serious damage at some point—maybe not right away but the cumulative effect will not be pretty. Fix the valve/actuator.

You and everyone at your plant will be happy it was fixed.

Force it to remain open at all times and there are going to be some very unhappy people at your plant.

And, read some of the past threads about IBH to understand what it does and why it’s important. I realize NOx emissions aren’t important in some parts of the world, but if a unit has a DLN combustion system and IBH it needs to be maintained and operated properly for longevity and revenue generation. Or it’s not going to be worth much when it’s a pile of scraps. And people are going to be looking for new jobs.

Fix the damn valve/actuator instead of looking for a dangerous workaround.

Consider this a ‘duty to warn’ that if you don’t fix the damn valve/actuator unit damage is going to happen and it might even result in injury or death to personnel. It’s very simple equipment that performs a very important AND protective function. That’s why the control system trips the unit when it doesn’t move properly!!!

Blessed day.

Thank you very much for your advices and as I said , I'll certainly tell whom it may concern.
 
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