On 03/15/2015 10:36 AM, Stewart C. Russell wrote: > On 2015-03-14 10:09 PM, David Thornton wrote: >> "Keeping time in sync" is a cornerstone to technology from gps to >> ssl, from hft to big data. > Absolutely. At the solar plant I audited the other week, I was amused > to see that the great big huge expensive grid protection and control > box was controlled via GPS sync. It's the cheapest way to maintain > grid frequency at the far end of the grid. And I mean /far/; 5 hours > west of Thunder Bay
Out in the middle of the Pacific??? The left coast is only 3 hours behind. A wavelength at 60 Hz is 5000 Km, though a bit shorter in power lines. With 3 phase power, there are 6 points within the cycle where sync can occur, so power phase will never be more than +- 30° out of sync, even before adjusting the alternators. So this means syncing 5000 or 10000 Km away is no different than 833 Km. For many years the LORAN C navigation network was used as a time base for the telecommunications industry to sync the telecom network. However, it only provided an accurate time base clock, not time of day. --- Talk Mailing List [email protected] http://gtalug.org/mailman/listinfo/talk
