INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

GE 9FA fast unload on shutdown

GE 9FA fast unload on shutdown

(OP)
On site we have a GE gas turbine 9FA DLN2.0 with package 4 compressor enhancement and Mark VI controller. We have noticed some times (6 out of 100 shutdown) a fast unload of GT until the breaker opening. IN more details when the plant is shutting down, GT decreases load up to 55 MW. Then waits until the ST generator breaker opens and ST is tripped, at that point takes normal shutdown command and reduces load. Normally, in the vast majority of cases, the unload is done within 2, 5-3 minutes. In some cases the GT unloaded fast, in 45-50 seconds. On all these 6 cases we have noticed no strange thing, no speed increase, no frequency increase, no strange alarm. We have only seen that the PM4 gas supply was kept until 52G breaker opening and then stopped. Usually the PM4 stops at 20-30 MW depending on combustion reference temperature TTRF1.

GE engineering was requested to ask, they said that the acceleration kicked in and unloaded the unit and the proposed to change the control constant FSKMIND4_SD from 15.7 to 17 % (Shutdown Value Of FSKMIND4[0]). Can you please share any similar experience? My understanding is that the controller works on OPEN LOOP and goes to fast unload in order to avoid loss of flame and in the same time keep a continuously decreasing firing temperature.

RE: GE 9FA fast unload on shutdown

There is only a handful of 9FAs with DLN 2.0 left, with Mark VI even fewer.u

I've heard about this fast unload but never actually experienced it. Do you have any high-speed data capture during shutdown to identify how the fast unload kicks in?

If GE Product Service recommended adjusting, minimally, FSKMIND4_SD you should do it. The start-up and shutdown controls are open loop. If during shutdown (L94X =1) any can flames out, the unit will abort the fired shutdown and turn off fuel. Completing the fired shutdown, helps keeping the Maintenance Factor down.





saludos.
a.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close