Overfueling with load grab 6-20MW in 5 seconds

Hi Guys, we have a GE frame 5 with 2 others at our facility, all where online~6 MW load . When switching gas to diesel on one we had a rapid load grab from 6-20 MW in about 5 seconds, the other 2 machines tripped on reverse power then we lost the 11kv system tripping the machine though the operator started to open the breaker too. We suspect the cause to be over fuelling, we have a old mk2 control system with no history. Should I be concern with the stresses from this acceleration and overfueled combustion or do you feel in your experience this is within the tolerance of the machine.
 
Mechanical-Man,

GE-design Frame 5 heavy duty gas turbines are BEASTS—especially Mk II-era machines. They will withstand (and have!) all kinds of abuse (unintentional and/or intentional) and just keep running.

It’s not likely the turbine suffered any damage unless it has been poorly maintained and severely abused.

Over-fueling is a phenomenon I have never heard before. Do you know why it occurred? You only seem interested in the mechanical well-being of the turbine, and that may be because you only have responsibility for the mechanical well-being of the machine. Some people (most) would be much more interested in why it happened and preventing it from happening in the future.

Anyway, unless the machine has been poorly maintained and/or abused it’s more than likely thinking to itself, “IsTHAT all you got??!? I can take that and a whole lot more with no trouble!!”

By the way, the reason you probably didn’t receive an earlier response is this is primarily a controls-related forum, and your question wasn’t really related to controls.

Best of luck!
 
Hi Guys, we have a GE frame 5 with 2 others at our facility, all where online~6 MW load . When switching gas to diesel on one we had a rapid load grab from 6-20 MW in about 5 seconds, the other 2 machines tripped on reverse power then we lost the 11kv system tripping the machine though the operator started to open the breaker too. We suspect the cause to be over fuelling, we have a old mk2 control system with no history. Should I be concern with the stresses from this acceleration and overfueled combustion or do you feel in your experience this is within the tolerance of the machine.
I am no expert on turbines... But as someone who worked long back with Mark II systems for sometime, I recall there used to be an acceleration control feature in MK II machines then...!! The feature (usually manifested as a light on the front panel) would kick in whenever the rate of change of rotational speed exceeded a preset curve...!! During most annual calibration of cards of MK II, there was a procedure to check the calibration of Acceleration Control Curve also...!! If you think the machine is accelerating at an uncomfortable rate, may be it would help keeping an eye on 'Acceleration Control Light' after the firing sequence is over...!! If not then may be have a look at Acceleration Control Card (Replace or calibrate, I guess)...!!

BTW, just a passing thot...!! MK II Systems, that I worked with, were perhaps just as, or perhaps much more, friendly & reliable than the later MK V or MK VI versions...!! To me, the only problem MK II systems suffered with, was the obsolescence of cards...!! On reliability front, imagine, two machines in operations for 25 years (that's a cumulative 50 years in a way) and JUST one card & one diode failure...!! Impressive, I feel...!!

Regards
 
Hi Guys, we have a GE frame 5 with 2 others at our facility, all where online~6 MW load . When switching gas to diesel on one we had a rapid load grab from 6-20 MW in about 5 seconds, the other 2 machines tripped on reverse power then we lost the 11kv system tripping the machine though the operator started to open the breaker too. We suspect the cause to be over fuelling, we have a old mk2 control system with no history. Should I be concern with the stresses from this acceleration and overfueled combustion or do you feel in your experience this is within the tolerance of the machine.
How does these units operating Droop /Isochronous mode...
A SLD or better plant configuration /operation can help us to support you...

To answer to your question, you better try to knwo why this occuring .....TO avoid it in the future...

James
 
The question (as is typical—WITHOUT a question mark for punctuation):

“Should I be concern with the stresses from this acceleration and overfueled combustion or do you feel in your experience this is within the tolerance of the machine.”

He is asking a mechanically-related question in a controls-related forum—which has been pointed out to the original poster, who seems uninterested (or perhaps they know why the over fueling occurred—so they’re just interested to know if machine can withstand the sudden fuel spike).
 
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