"scott" <sco### [at] scottcom> wrote:
> >  If I'm not mistaken, this is so severely imposed that an electric company
> > feeding the system with even the tiniest discrepance in the frequency or
> > phase is automatically dropped.
>
> It doesn't work like that, you don't get to choose the frequency or phase of
> your generator when it is connected to the system.
>
> An analogy is if you imagine 100 cars all fixed end to end on a track going
> at 100 km/hr.  The steepness of the track can be thought of as the current
> demand, each car as a power station, and the speed as the frequency.  It's
> the job of the controllers of the entire system to predict demand and ask
> more or less cars to join the train, and to tell each driver how much power
> to generate.  As an individual you can't set your own speed and be "out of
> sync" with everyone else, by definition of being connected to the system you
> are generating the same frequency and phase as everyone else.

To expand on what Scott has said. (In a past life I used to work on the
electronic governors of Gas Turbine power generators.)

All the generators in a grid will be at the same frequency and phase. As you
bring a generator online you must wait until the oncoming generator is in phase
with the grid before connecting it. If it is slightly out of phase it creates a
nice bang :) As the load on the grid increases the frequency will try to drop
but the individual governors will increase the throttle valve, supplying the
fuel, to keep it steady. The line voltage will drop instead.

cabling.

Stephen

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