From last two days we are facing problem in our frame V machine, the parameters Speed, SRV, P2 , GCV , IGV, CPD and exhaust temperatures are varying. We are unable to identify the origin for this as all the above parameters are inter linked with each other. One thing we had done is, we have kept the IGV temperature control in manual mode and found there are still fluctuations in SRV, GCV , P2 , Speed fluctuations slightly reduced. The variations of parameters at 19.5 mw are as follows,<pre>
Speed 5103 rpm to 5115 rpm (approx)
SRV 42 % to 46 % (approx)
P2 14.5 kg to 15.3 kg (approx)
GCV 51.5 % to 53.5 % (approx)
IGV 57 % to 61 % with exhaust temperature varying from 541 to 543.</pre>
We reduced the load from 19.5 to 18.5 and found the fluctuations slightly got reduced.

I will be thankful if some one help me in sorting this........

 

Hello...

I have an interest in looking into this closer for you.

Are you willing to share your historical archives leading up to this point?

We would like to prove our data analysis tools similar to what GE uses, this seems like a good project for that.

No thoughts yet, for what you have described.

 

If the unit is operating on a grid of some size with other units and the speed is fluctuating then the grid frequency is fluctuating. And the P2 pressure reference will also fluctuate as the speed fluctuates, and if the gas fuel supply pressure isn't very stable to begin with then the problem will be worsened.

We would need much more information to be of much more help.

 

Thank you for immediate response sir,

The inlet gas supply is being maintained steadily and the system is not connected to grid. it is in ISOCH mode of operation. Ours is a captive powerplant. we are having 3 machines, 2 frame 3 machines and 1 frame 5 machine, all run individually in ISOCH mode.

 

Mark,

You have not told us <b>WHEN</b> this problem started (which is VERY important information).

<b>Unless all the turbine control systems have some kind of Isochronous Load Sharing scheme which allows them to stably control frequency, then it's very likely the chosen operating modes are the cause for the problem.</b>

Is there some kind of Isoch Load Sharing scheme in use at your site that allows the three units to all operated in Isoch Speed Control mode?

Isoch Load Sharing scheme can be very simple or very complicated. They all involve some form of communication between the turbine control systems, or even some "higher-level" control system sending signals to all three turbine control systems. Everything has to work nearly perfectly for multiple turbines to operate in Isoch Speed Control mode at the same time.

This presumes the Frame 3 two-shaft machines are also generator drives. They would probably not see as much fluctuation as the single-shaft machine, but there should be some instability visible--at a minimum Frame 3 generator speeds/frequencies should be changing at the same time and by the same amount as the Frame 5's speed/frequency.

Please try to remember when posting for help to a forum like this: We are not at your site. And, your site is not like every other site, even if they have Frame 3's and Frame 5's. Every Frame 3 is not like every other Frame 3, and every Frame 5 is not like every other Frame 5. Not every site runs as a power island (separated from a larger utility or electrical grid with other generators and their prime movers).

If you want the faster, most concise reply to your query you need to provide as much information about your site, it's configuration, what troubleshooting you have done and what the results were (more than just, "Nothing we have tried solved the problem;" we need to know what was done and what the results were).

Otherwise, you are going to keep receiving requests for information and data and you aren't going to be very happy with the long exchanges.

So, please help us help you by providing as much information as possible about your site, how it is normally operated, etc., so that we can provide faster, more concise responses. Everyone will be happier.

And, lastly, the thing that separates this site from many others on the World Wide Web is that most of those asking questions or asking for help write back to let others know if the information provided was helpful or not. That way, others who may read the thread weeks, months, or years later will know if the problem was resolved with the information/help provided. That's the real value of this site: being able to read the feedback from those who ask for help or information. Sure, we, might help one person at a time without any feedback from that person; but if that person provides feedback then many people can read about a problem similar to theirs and know if the suggested solution was successful and then apply that to their problem--hopefully with a successful resolution.

But for now, if you want more assistance you are going to have to provide a lot more information.