We are using GE 9FA gas turbine in our CCPP. In IGV control page, there is a temperature matching button. OFF position is selected. Does anybody have information about this system? What is the function of this system? and is there any risk to activate this system? Thanks for assistance...

 

If properly enabled (and lots of buttons on GE Mark V HMI Displays are not properly enabled in sequencing), Temperature Matching will look at a setpoint (the Temperature Matching Setpoint, which should be another button on the display, or it might come from an analog input to the Speedtronic) and adjust the exhaust temperature by changing load (which can involve varying the IGV angle) to match the setpoint.

The setpoint is usually derived by looking at some steam temperature, or some boiler metal temperature. By using the Speedtronic to "match" the temperature setpoint the idea is to help speed up reaching, or not to exceed, the desired steam temperature or boiler metal temperature setpoint.

Temperature matching is typically only used during start-up of the plant, and especially if there is no bypass stack or damper in the exhaust, though that's not always the determining factor.

It's a great thing when it works properly, and that can take some tweaking. Sometimes, a lot of tweaking, er, uh, tuning.

If you've never used it on your site before now, don't start now. Not without a thorough understanding of how it works, when to use it, where the setpoint comes from, any multiplier which might be involved with the setpoint, and without some there to help with the tuning that is necessary to make it work properly.

 

Thank you very much your explanation. It will help us to decide putting into service this function. If you have any manual about this system and share with us, we will be very grate full. Thanks again for your assistance.

 

If you have a GE-packaged and -provided machine, you will have a document called the Control Specification. That document will usually have some explanation of Temperature Matching.

There may also be something in the GE-provided Instruction Manuals on Temperature Matching.

Remember, when reading any written description of GE features provided by GE, you are reading them to obtain an understanding of the intent of the feature, not necessarily precisely how it works on your machine. Precisely how it works or was implemented on your machine is a function of how it was configured, and what is in the sequencing that is running in your turbine control panel.

Hopefully you, or someone at your plant, can have a look at the sequencing (I believe you said you had a Mark V) and work through the scheme. There are usually some comments in the sequencing which may be helpful.

A very large proportion of Frame 9FA machine owners/operators have CSAs (Contractual Service Agreements) or LTSAs (Long-term Service Agreements) with GE. If you have one of these, you should be able to work through your Contract Performance Manager to get some assistance with this.

But, if this hasn't been in operation since commissioning, it's a reasonable bet that it was likely never properly or fully commissioned.

Most times this feature is only used on machines that are load following or dispatched, and started and stopped on a frequent basis. And, many times it's necessary only because the boiler (heat recovery steam generator; waste heat recovery boiler; whatever it's called at your site) can't take large temperature swings during frequent start-ups. So, if you haven't been using this is it really necessary?

Another reason to have someone who's knowledgeable in the scheme to come and work through the commissioning and tuning of the feature. Unless you or someone on your site can read and understand the Mark V (?) sequencing and make sure that the temperature matching input(s) are working correctly (from the HMI display and/or an analog input or via GSM or some other digital input) and can work through the scaling necessary, having someone who has the knowledge or who can get assistance from an engineering organization with the knowledge would be very helpful and most likely cost-effective.