manual synchronization
manual synchronization
(OP)
Hi All,
If you miss the opportunity to manually sync when the scope needle is moving clockwise is it okay to immediately slow the prime mover down enough for the scope to rotate counter clockwise and sync in?
If you miss the opportunity to manually sync when the scope needle is moving clockwise is it okay to immediately slow the prime mover down enough for the scope to rotate counter clockwise and sync in?






RE: manual synchronization
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: manual synchronization
You are better to slow the prime mover a little bit and catch it on the next revolution of the 'scope. If you have reverse power protection you may trip it by sync'ing on a falling 'scope.
If you miss your sync, you may be running a little too fast in any event.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: manual synchronization
Rafiq Bulsara
http://www.srengineersct.com
RE: manual synchronization
RE: manual synchronization
I did see a station where closing with the scope turning counter clockwise was sometimes smoother. I've mentioned that plant before. There was a hard wired, 30 degree phase angle wired into the synchroscope.
Does your scope stay at 12:00 oclock after the breaker is closed?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: manual synchronization
What Rafiq saied (and other guys too
Best Regards.
Slava
RE: manual synchronization
RE: manual synchronization
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: manual synchronization
Scotty may be on to something.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: manual synchronization
Thanks again!
RE: manual synchronization
You will know when you have performed a 'rough' sync - i.e. when the phase angle is too far out, you have a ridiculous voltage mismatch, or the frequencies don't match properly: the ammeter dials will bounce like crazy, the mechanical shock will show on the vibration instruments all the way down the machine train, the excitation may trip. Get it too far wrong and you will probably break something expensive.
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: manual synchronization
Alan
RE: manual synchronization
if you miss the close, why not leave steam flow as is and catch it at the next 12.
RE: manual synchronization
Scotty, reading an earlier post, sounds like you have 'been there, done that' for you to have been able to describe it in such detail.
rmw
RE: manual synchronization
I did one careless sync on a medium-sized machine and it scared me enough to be very cautious in future. I've investigated a few bad auto-syncs where a faulty sync relay was slow in sending the close signal, and a series of them with a bad governor. The worst one (auto-sync, faulty sync relay) was bad enough to feel the shock on the unit from where I was in the control room. All the lights on site flickered, so we must have bumped the 275kV network quite hard. A colleague was up on the machine at the time and when he came down he was an ashen grey colour, babbling about how the whole machine had jumped from side-to-side along the shaftline. It must have been a scary moment up there.
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: manual synchronization
RE: manual synchronization
Wrong generator synchronization ?
thread238-130828: Wrong generator synchronization ?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: manual synchronization
BTW, that machine is still working. The flapping noise I mentioned there was due to the rotor leads (going under the main exciter armature) not being properly wedged tight. We rewedged the rotor leads and the noise went away.
[I know that my feedback a bit tardy]
Muthu
www.edison.co.in
RE: manual synchronization
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: manual synchronization
The frequency during synchronization is also noticed on the distributor valve of the governor at the instance of synchronization. This is very apparent on Woodward governors, where the speed error dynamic swing envelope causes gate movement.
The shockwave during an out of sync event is caused from the synchronizing torque of the generator acceleration/deceleration of the rotor to the 0 degree reference. In other words, I too would grunt loudly trying to rotate 200TONs immediately.
Perfect synch's will achieve 0MW and 0MQ upon sync. Deviation of the values means you have an offset in speed error or terminal voltage. A perfect sync will result in a near silent breaker close (you should only hear the operating mechanism). Always account for the GSU tap ratio in the sync running/incoming bus PT signal, depending on having a LS-GCB or HS-GCB.