Sir i want know how the calculation for turbine temperatue ref (TTRF) is calculated by GE.
Is TTRF calculation depends cpd bais, fsr bais and isothermal setpoint?

 

@paras0701,

TTRF is a value used to determine when combustion mode changes (switching) should be done as a machine is loaded and unloaded. Most people think combustion mode changes are a function of load (MW), but that's not true though they do happen at some more typical ranges they are not determined by load.

Many variables and some Control Constants have been used over the last 30 years to calculate the turbine firing temperature reference--which is, as you noted, a calculated value. TTRF is used to approximate the temperature of the hot gases entering and passing through the first stage turbine nozzles of a machine equipped with DLN combustors. There have been several, sometimes subtle, changes to the way TTRF is calculated over time and we don't know how old the machine is that you are working on/with, what turbine control system is used to control, monitor and protect the machine and what, if any, problems which you might be experiencing or working on to help resolve.

GE uses algorithmic "blocks" to do many calculations in digital Mark* turbine control systems. While it's not possible to see precisely what happens INSIDE the block, all of the inputs to the block are almost always shown on the left side of the block and all of the outputs are almost always shown on the right side of the block, and the inputs and internal calculations work from left to right as the block makes the calculations.

It should be possible to find the "origin" of TTRF (the block that calculates and outputs the value of TTRF) using the method GE provides based on the version of Mark* turbine control system in use on the machine. There is usually a graphical display method for Mark* V, Mark* VI* and Mark* VIe turbine control systems that can display blocks and rungs and function blocks (a fancy term for relay ladder-based logic) so by searching for TTRF you should be able to find the block that calculates and outputs TTRF and then you can see what the inputs to the calculation are by looking at the signals on the left side of the block. Occasionally, but not very often in actual practice, one or maybe two or three "inputs" to a calculation appear "inside" the block, but that is very rare. Most often, the blocks may use the previous value of a signal to help smooth out large possible swings in a value's calculation. The Mark* V Application Manual (if the machine uses a Mark* V) has some relatively good descriptions of some blocks and the basics are the same for almost all blocks. Toolbox and ToolboxST (used with Mark* VI and Mark* VIe) have a pretty decent Help feature for most blocks, but it can be difficult to read and interpret. However, if you're just looking for inputs to the calculation of TTRF you should be able to easily find them using the graphical display method of the version of the Mark* on the machine you are working on or trying to help with.

If you are experiencing what is perceived to be a problem with TTRF, please try to describe it here and we can try to help. Tell us the Frame size of the machine, and the version of the Mark* turbine control system of the machine and we can be more helpful. But, without lots of more information we can't be of much more help.

Finally, if you are trying to build a simulator or program some kind of turbine control system to "duplicate" what the Mark* does you should know that GE considers DLN technology--including the calculation of TTRF--to be company proprietary information and doesn't really publish much about how DLN technology is accomplished. While it has been done before, sometimes it took some serious tweaking (tuning; adjustments; revisions; reprogramming) to make it work reasonably well.

 

Thanks for reply sir..
Just want to know basic equation of TTRF...How it is calculated and what inputs it takes..just for knowledge
My plant have GE MS6001B machine
With Mark VIe control system..
Its having a multifuel function, in which we can use total 4 fuels viz hsd and lco - NG And Propane

 

@paras0701,

You'll need to use ToolboxST to look at the application code running in the Mark* VIe. If you connect to the Mark* VIe while using it you can see the actual input values (usually in green color) feeding into the block. The calculation is not something that is readily visible, and it may actually involve some maths using arrays to form graphs/functions that are used to assist with the final calculation. It can be very complicated. GE is also apparently switching lots of algorithmic blocks to what are called "macros" which can be extremely difficult to read and interpret and follow (to protect their proprietary information).

As long as you use ToolboxST in Operator mode you can accidentally change the application code nor can you trip the machine using it (ALWAYS a concern of supervisors and Plant Managers). Some newer versions of CIMPLICITY and/or PROFICY MACHINE EDITION have a feature that by hovering the cursor over a value or signal name (it's like most things with GE: consistently inconsistent) and clicking on it (I can't recall if it's a left click or a right click) it can automatically open ToolboxST and take you the location in the application code where the signal value is written to (where it "originates"). Again, it seems to be hit or miss with this feature though it does seem to be appearing on more and more GE HMIs these days; if only it were consistently applied and configured it would be very, very useful.

I don't have any pdfs of Mark* VIe application code, but I do have some Mark* V CSP (Control Sequence Program) which has what may be the same TTRF algorithmic block calculation. If I get some time in the next couple of days (no promises), I will post a snippet of the block to this thread and you can get a feel for what the inputs to the block/calculation are.

 

Thank you sir for reply...if you get the data please share.it will help for better understanding of ttrf..again thank you sir..

 

Some newer versions of CIMPLICITY and/or PROFICY MACHINE EDITION have a feature that by hovering the cursor over a value or signal name (it's like most things with GE: consistently inconsistent) and clicking on it (I can't recall if it's a left click or a right click) it can automatically open ToolboxST and take you the location in the application code where the signal value is written to (where it "originates"). Again, it seems to be hit or miss with this feature though it does seem to be appearing on more and more GE HMIs these days; if only it were consistently applied and configured it would be very, very useful.

On cimplicity screen, if you right click on any of the interested signal, then "go to definition in logic" should take you to the correct spot. If its not at all working for all the signals, then it must be a configuration issue. Recommended to raise a ticket with OEM.

For some variables - the so called "intrinsic variables", it just goes to root node and stops.