Re: Wacky Weekend: NERC to relax power grid frequency strictures

[Michael DeMan <nanog () deman com>]

It ismy understanding also that most commercial grade gensets have built into the ATS logic that when utility power 
comesback online, that the transfer back to utility power is coordinated with the ATS driving the generator until both 
frequency and phases are within a user specified range?

- mike

On Jun 25, 2011, at 3:12 PM, Leo Bicknell <bicknell () ufp org> wrote:

> In a message written on Fri, Jun 24, 2011 at 06:29:14PM -0400, Jay Ashworth wrote:
> > I believe the answer to that question is contained here:
> >
> >  http://yarchive.net/car/rv/generator_synchronization.html [1]
>
> I wouldn't use a colo that had to sync their generator to the grid.
> That is a bad design.
>
> Critical load should be on a battery or flywheel system.  When the
> utility is bad (including out) the load should be on the battery or
> flywheel for 5-15 seconds before the generators start.  The generators
> need to sync to each other.
>
> Essential load (think lighting, AC units) get dropped completely for
> 30-60 seconds until the generators are stable, and then that load gets
> hooked back in.
>
> I have never seen a generator that syncs to the utility for live, no
> break transfer.  I'm sure such a thing exists, but that sounds crazy
> dangerous to me.  Generators sync to each other, not the utility.
>
> -- 
>       Leo Bicknell - bicknell () ufp org - CCIE 3440
>        PGP keys at http://www.ufp.org/~bicknell/