Does the electric power grid use a common time reference? If so what is it? Greenwich Mean Time or other? Is the most likely time for a Y2K problem to occur at midnight local time, or midnight at the time reference?

-- Anonymous, January 17, 1999

Answers

I received the following email the other day regarding just this subject:

Dear Mr. Cowles,

The grid is not on local time as has been reported in many places.
The grid runs on UTC or Greenwich time, so the year rolls over to
2000 at midnight UTC which is 6 PM CST or 7 PM EST.

Also many computers used in business are on UTC.  Companies that are
international corporations set their computers up to UTC because it is
easier when doing commerce across many different time zones. 

Many y2k sources ignore that fact.

This is the information I got from Mr Wilcox of Northern States Power 
in Sioux Falls, SD. (about the grid)

Sincerely,

Fred Lehmann
Sioux Falls, SD

This pretty much squares with my own personal observations of time keeping and synchronization equipment in switchyard relay rooms, although (as has happened once or twice in the past) I could be wrong.

-- Anonymous, January 17, 1999

I've been a grid operator or dispatcher for years. I would like to help set this question straight. UTC is used for many things in the power system, primarily for time synchronization-getting very accurate time. I just asked our SCADA expert and he verified that the time synch from WWV or GPS is UTC or Greenwich Mean time. But the SCADA system corrects UTC the required number of hours to put our operations on local time. By the way, he said SCADA can run just fine on its own internal clock and has done so several times in the past.

I am in a control room right now and the dispatchers are dealing with central time east of us and pacific time to the west. The Eastern Interconnection may have agreed upon using Central time but I am pretty sure an attempt by NERC to use a common time zone for operations across the country was voted down.

-- Anonymous, January 22, 1999