Yesterday’s massive power outage, involving millions of customers in Arizona, Southern California, and Mexico, is apparently due to human error, although an investigation is still underway. Power is now restored or is in the process of being restored.

Time lapse of a 500 kv line construction. Really cool. Two minutes:

Diagram of an electrical system.

Wikipedia commons, diagram of an electrical system.

At about 3:30 PM yesterday, the North Gila – Hassayampa 500 kV transmission line near Yuma went offline.

Read more:

High-tension transmission lines are the lines atop the 1400-foot tall lattice structures, and they move electricity between a generating power plant and uploading substation to a downloading substation. In this case, the generating station providing the power is the Palo Verde Nuclear Generating Station, the largest in the United States, and it is located about 45 miles west of Phoenix, in Wintersburg, AZ.

This line connects to the Hassayampa switchyard, and serves as a major power conduit to Southern California:

“From that switchyard, the power goes west out of there on the North Gila – Hassayampa 500 kV line, and that is the only line that goes from Arizona to San Diego County, and it goes through Yuma,” explained Jeff Lane, spokesman for the Salt River Project, which operates the Hassayampa Switchyard.

Read more:

Since electricity cannot be stored, except in certain cases such as batteries, there must be a close match between supply and demand, to prevent major blackouts. This particular outage was the unintentional result of a single employee carrying out a maintenance procedure.

The question that remains is why the outage was not localized to the Yuma area, as it should have been. This is under investigation.

Here is a comment from one who experienced the power failure, hat tip ubetchaiam:

Since I lived thru this -*G*- let me add to the diary with a local explanation:

You can store electricity btw; think batteries. But everything went down including cell phone service; really was -I hope_ a wake up call to people regarding how dependent they are on electricity and what life is like without it. And how quiet it can be even in an urban area without electricity.

Does make one understand where ‘early to bed,early to rise came from. *G*

And I learned that if you’re going to read by candlelight, you better have a LOT of them. I anticipate a lot of generators being sold in the near term. *G*

Amazing how easy and quickly a high-tension transmission line can be knocked out, relieving several million people of power for the night, closing an airport and a couple of nuclear generating plants in remote locations, leaving people trapped in elevators, with officials scrambling to restore power to hospitals. As it turns out, this 500 kv transmission line supplies not only the Yuma and surrounding areas but also a major portion of Southern California, including, in pertinent part, San Diego, as well as portions of Orange County to the north, and Tijuana, Mexico, to the south.

This sort of event makes fondling the passing public, including old people and children, in airports, in the name of homeland security seem pretty silly. I have to re-laugh an event that happened with us a few months ago. While I was in a meeting downtown and my husband was waiting outside, he decided to do some back stretches and Tai Chi in the gravel parking lot while he was waiting for me. But since he was parked near the local 911 dispatch tower, someone called the cops, and homeland security was alerted. By the time the three cops cars arrived and surrounded the vehicle, he had walked to the Public Library. So that left me, in the parking lot, explaining that he had been doing some Tai Chi, and them, explaining to me, that his actions were a homeland security issue.

We need to focus on some real issues in this country, get some jobs going, figure out and fix the infrastructure, and quit picking on the passing public constantly.


Electric power transmission:</a

The Yuma Sun article.

The Palo Verde Nuclear Generating Station wiki:

NPR updates.


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