On Fri, 03 May 2013 12:11:19 +0100, The Natural Philosopher
wrote:

On 03/05/13 09:46, Andy Champ wrote:
On 03/05/2013 00:17, The Natural Philosopher wrote:
The way it goes is this. You start your powerstation and then when its
in phase with the grid, you connect it. At this point if you pull torque
off it. it will be a motor driven BY the grid, and as you increase
torque on it, it will start to phase lead the grid slightly and push
power onto it. You can control the voltage using the exciters - you
match that to the grid voltage.

OK, I think I get it. It's being a small fixed amount ahead of the
grid phase that means you are pushing power in. If you shove less
steam into the turbine you'll lead by less, and be putting less
current in even though your RMS voltage is the same.

But no-one answered my question - what has overall control of the grid
frequency? Some guy with a meter and a phone, calling the CCGT stations?

Andy
essentially yes.

at one level.

at another level the jennys are on governors. they will push harder when
the freq drops.

the grid central gets called in when the jennys cant cope and the freq.
is still falling...

Who or what do you mean by the term "grid central"

--