Can anyone explain the roles/function and effect of control constants in GE gas turbines ? What will happen when we increase or decrease the value of the constant and what it will be its effect? How to calculate and enter the values of the constants? FSRSU , FSRACC , FSK, FSRMINN, FSRMINU, FKJSU, TAKL1, TMKGV.... temperature constant arrays, curves etc. I know there so many constants but need to understand that. If anyone has any documents based on constant calculation can share @ [email protected].

Thanks

 

Control Constants (a somewhat confusing choice of words) are, as you have determined, variable values that are used in calculations for control and protection of the turbine and auxiliaries. JUST BECAUSE CONTROL CONSTANTS CAN BE CHANGED DOES NOT MEAN THEY SHOULD BE CHANGED. Especially if one doesn't understand what the effects of making the changes are.

We have ZERO idea of your familiarity with GE Mark* turbine controls and, more importantly, GE heavy duty gas turbine control philosophy for turbine and auxiliary control and protection. One has to understand how to read and "interpret" the programming and configuration that is downloaded to and runs in a Mark* turbine control panel BEFORE one even considers making any kind of change--ESPECIALLY TO MANY OF THE CONTROL CONSTANTS YOU LISTED (and many you did not!).

THERE IS NO document that describes how to calculate the values of Control Constants. That's considered proprietary information of GE. It can be gleaned from understanding the programming (in newer digital Mark* turbine control systems the programming is called application code). At least there was no such document in the 30+ years I worked on Mark* turbine control systems. We all learned by learning how the programming and configuration is done, AND reading the Control Specification which was provided with every Mark* turbine control system that was shipped with a turbine. There is a LOT of good information in that document, but it's usually very terse and brief and leaves a lot to be desired--in the beginning. It is the list of all the Control Constants and I/O Configuration parameters for the panel it was developed for. There is some description of control and protection schemes and functions, but not all of them--not by any stretch of the imagination.

One should NEVER change critical Control Constants (such as exhaust temperature control values!) without fully understanding the knock-on effects.

If this is about understanding how to replicate a Mark* turbine control system for a replacement, well, you're on your own. It's going to take a lot of review and research to understand what the algorithm that's using the Control Constants does--and then it will become clear(er) how the value was originally calculated.

If this is about tuning or adjusting operation for some purpose, it's still a process of research and getting to know how the turbine is being controlled to know what the limits of adjustment are. AND FOR CHANGING EXHAUST TEMPERATURE CONTROL PARAMETERS--UNLESS SOMEONE KNOWS A LOT ABOUT THE COMBUSTION HARDWARE IN THE MACHINE CHANGING THE PARAMETERS TO INCREASE THE MAXIMUM ALLOWABLE EXHAUST TEMPERATURE IS PROBABLY GOING TO LEAD TO PREMATURE FAILURE OF COMBUSTION HARDWARE--AND POSSIBLE SERIOUS CATASTROPHIC AND VERY EXPENSIVE CONSEQUENCES.

Changing start-up Control Constants is also fraught with some hidden issues, because GE uses some start-up values in the shutdown control scheme, so changing a Control Constant to affect some result on start-up can have an undesired effect on shutdown. (And, of course, the Mark* ALWAYS gets blamed for these kind of knock-on effects....)

Best of luck. Without a clearer understanding of what your intent is and needs are there's not much more to be said. Again, at least until a couple of years ago there was no document that explained or detailed how individual Control Constant values were calculated.

 

Control Constants (a somewhat confusing choice of words) are, as you have determined, variable values that are used in calculations for control and protection of the turbine and auxiliaries. JUST BECAUSE CONTROL CONSTANTS CAN BE CHANGED DOES NOT MEAN THEY SHOULD BE CHANGED. Especially if one doesn't understand what the effects of making the changes are.

We have ZERO idea of your familiarity with GE Mark* turbine controls and, more importantly, GE heavy duty gas turbine control philosophy for turbine and auxiliary control and protection. One has to understand how to read and "interpret" the programming and configuration that is downloaded to and runs in a Mark* turbine control panel BEFORE one even considers making any kind of change--ESPECIALLY TO MANY OF THE CONTROL CONSTANTS YOU LISTED (and many you did not!).

THERE IS NO document that describes how to calculate the values of Control Constants. That's considered proprietary information of GE. It can be gleaned from understanding the programming (in newer digital Mark* turbine control systems the programming is called application code). At least there was no such document in the 30+ years I worked on Mark* turbine control systems. We all learned by learning how the programming and configuration is done, AND reading the Control Specification which was provided with every Mark* turbine control system that was shipped with a turbine. There is a LOT of good information in that document, but it's usually very terse and brief and leaves a lot to be desired--in the beginning. It is the list of all the Control Constants and I/O Configuration parameters for the panel it was developed for. There is some description of control and protection schemes and functions, but not all of them--not by any stretch of the imagination.

One should NEVER change critical Control Constants (such as exhaust temperature control values!) without fully understanding the knock-on effects.

If this is about understanding how to replicate a Mark* turbine control system for a replacement, well, you're on your own. It's going to take a lot of review and research to understand what the algorithm that's using the Control Constants does--and then it will become clear(er) how the value was originally calculated.

If this is about tuning or adjusting operation for some purpose, it's still a process of research and getting to know how the turbine is being controlled to know what the limits of adjustment are. AND FOR CHANGING EXHAUST TEMPERATURE CONTROL PARAMETERS--UNLESS SOMEONE KNOWS A LOT ABOUT THE COMBUSTION HARDWARE IN THE MACHINE CHANGING THE PARAMETERS TO INCREASE THE MAXIMUM ALLOWABLE EXHAUST TEMPERATURE IS PROBABLY GOING TO LEAD TO PREMATURE FAILURE OF COMBUSTION HARDWARE--AND POSSIBLE SERIOUS CATASTROPHIC AND VERY EXPENSIVE CONSEQUENCES.

Changing start-up Control Constants is also fraught with some hidden issues, because GE uses some start-up values in the shutdown control scheme, so changing a Control Constant to affect some result on start-up can have an undesired effect on shutdown. (And, of course, the Mark* ALWAYS gets blamed for these kind of knock-on effects....)

Best of luck. Without a clearer understanding of what your intent is and needs are there's not much more to be said. Again, at least until a couple of years ago there was no document that explained or detailed how individual Control Constant values were calculated.

WTF?
Thanks for your reply and apologizes for my late response. I agree with you that experience will make you more familiar to the constants. I just want to know how the constants are derived. Some might be based on metallurgical properties, environmental conditions etc. One of my known engineer said how acceleration constant is derived viz if the the turbine has to reach 100% speed from the point of ignition in 8 minutes then divide the % speed by time and through that acceleration constant can be derived. I was just asking such things for the derivation of constants.

Thanks