On Tue, 2010-06-08 at 15:50 -0400, Charles Craft wrote:
> I had one question that turned into two after Googling around. :-)
> 
> 1. Saw a blurb today about a power cable between countries and got me 
> thinking -
> how do they synchronize all the power stations on a grid?
> If it's 60HZ (US) then each cycle is 16.67ms and depending where you are 
> in the cycle
> the slope is pretty steep so potential for voltage mis-match is large?

The "old" way was you had a light bulb across the grid and your
generator. You manually adjusted your generation until the bulb stayed
"off" (it would blink on and off if you were off in frequency and it was
remain illuminated with a steady brightness when your frequency was
correct but your phase was off), which meant you were both phase and
frequency matched. Then you flip the knife switch and boom, you're on
the grid. After that point the generator stays synced.

We did this procedure in a power electronics lab in university, it's
pretty tricky, and God help you if you flip that switch without it being
properly synced (some students got impatient, very dumb...).

These days I'm sure the equivalent procedure is done electronically with
most generation sources.

TTYL

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