Ge7fa upgrade of everything mk6 to mk6e. Turbine upgrade also. Try to crank and shaft starts turning wrong way then stops and returns to 6 rpm on tg. Anyone seen this or have any ideas? Thanks

 

Was anything changed/upgraded in the generator excitation system? And/Or the LCI?

 

Yes it was upgraded also. Internal parts to lci is same. Just a controls upgrade. ls2100

 

It's a slow none violent motion.

 

I'm NOT an LCI expert by any stretch of the imagination, but if I recall correctly the LCI "catches" the generator rotor whilst it's on turning gear and accelerates it (in the proper direction)--presuming the output of the LCI is properly connected to the generator stator windings. The LCI is essentially just a giant variable frequency drive (and the generator is essentially a giant three-phase "motor" at this point) that starts out at a very low frequency (6 RPM, which for a 60 Hz machine would be 0.1 Hz) and then increases the output frequency to accelerate the shaft to purge speed, firing speed and finally to approximately 95% speed at which time the LCI output to the generator ("motor") stator is disconnected and the generator actually becomes a generator.

It's difficult for me to understand how the LCI output could be misconnected, or even how the LCI control could miscalculate the rotation of the generator ("motor") rotor--but again, I'm NOT a LCI expert.

I'm wondering if the turning gear motor is running backwards (because it was reconnected improperly).?.?.? I don't know how that could actually happen because of the SSS clutch between the turning gear mechanism and the generator rotor.

It's times like this I wish I would have gotten more familiar with the LCI, but, I had my hands FULL with commissioning the turbine control system. Not to mention construction was ALWAYS late and commissioning was ALWAYS squeezed for time (because the start-up date NEVER changes even though construction is late and everyone believes the commissioning personnel can work longer hours and double shifts while the unit is still being built and wired).

Anyway, the work was cool; just wish I'd learnt a little more about the LCI....

It would be very interesting and much appreciated if you could write back to let us know how this is resolved!

 

Yes that is how it all works and your thought is the same as everyone here. I'll post what is found once we figure it out. The experts are in route and lots of engineers looking at data. Maybe we will get an update tomorrow. We have other crazy shit happening also. Somehow we line up our 89s and we do so on another unit too. Our 52ss are staying closed after unit is online. On the unit that should be good. Thanks for your reply

 

Update issue resolved. Turned out to be a fiber cable was swapped in the lci which seems to be the same as swapping phases and was actually trying to spin it backwards. But the tg anti rotation was stopping it so it was only able to a small amount.

 

Jax316... Welcome to Control.com.
Please provide system parameters... Volts, kVA, Rated Amperes, Excitation Volts, etc.
Regards, Phil Corso
Nevermind !

 

Jax316...
I'm curious. Is the "LCI" furnished by ABB?
Regards, Phil Corso

 

Phil Corso,

LCI (Load-Commutated Inverter) was the original "name" for the high-voltage frequency converter design GE developed to use for starting GE-design heavy duty gas turbines using the generator (as a motor) instead of a dedicated starting motor (which would have been physically HUGE and greatly contributed to the cost and complexity of the total gas turbine-generator design). They have also been called static starters, among other terms. The original poster mentioned LS2100, which is a GE designation for one of their designs. While GE is not completely averse to using another manufacturer's equipment (they do it from time to time, and more often when it's the least expensive alternative) they generally try not to if it's possible. The European division of GE Power also uses LCIs/static starters from different manufacturers in Europe on occasion (usually when required by the laws or regulations of the country where the equipment is being installed).

 

Jax316...
All though the problem with your system was resolved, I'm still interested in the system's Electrical Parameters ! If you want my "WHY", then I suggest you use the Search Process (Magnifying Glass) located on the Headline of this topic, for the forum "ABB-6080! Unitrol !"
Regards, and Merry Christmas to All!
Phil Corso ([email protected])

 

When I get a chance I'll reply back to you. We have t1 vib issues and going back into it.