Yesterday, San Diego experienced two relatively brief blackouts, totalling 27 minutes in duration (at my location.) Friends reported many traffic lights flashing red at major intersections, rather than normal red/green cycling, with resultant traffic jams.

Radio KGB 101.5 just reported that yesterday's San Diego area blackouts were caused by a "computer glitch". The I.S.O. grid margin was fortunately high, due to cool weather, when this occurred.

Are Y2K related embedded system failures still occurring? Or are there still significant grid bottlenecks? And how serious would these minor blackouts have been if the "computer glitch" had occurred with the grid at zero margin, such as on July 3? Would a major cascading blackout have been the result?

Will the good luck, with cool weather, and "computer glitches" hitting when grid margin is high, continue?

Let's hope for the best, but prepare for the worst.

-- Robert Riggs (rxr.999@worldnet.att.net), July 18, 2001

Answers

Headline: Protection system blamed in outage

Source: UNION-TRIBUNE [San Diego] 18 July 2001

URL: http://www.signonsandiego.com/news/uniontrib/wed/metro/news_7m18outage .html

About 134,000 utility customers lost electricity yesterday when a system intended to protect the power grid was inadvertently triggered.

The outage hit at 2:50 p.m. and affected San Diego Gas & Electric customers in communities throughout the region. Eighty percent of the affected customers had power restored within 10 minutes. All the power was back by 3:30 p.m.

The built-in protection system is supposed to shut off power when it senses damage to equipment or other problems that might harm the transmission grid, said company spokesman Michael Clark. He said the cause of the outage was under investigation.

Company officials stressed that the interruption was not a rolling blackout or related to power shortages.

-- Andre Weltman (aweltman@state.pa.us), July 19, 2001.