I've done some research... and when they say "severed", they don't mean physically cut.
These high voltage lines and systems have safety mechanisms built in that cut power to the high voltage lines when there is a power disruption. So, when they say severed, they mean they had sort of disconnected themselves from the grid for safety reasons. When the guy flipped the switch in Yuma, it caused a power surge that brought down both high voltage lines into San Diego. When those went down, San Onofre, also shut down for safety reasons.
Similar thing happened in the big outage in the Northeast a few winters back which caused that domino effect that took out power to 50 million people.
(In full disclosure, I had worked at SDG&E for almost 10 years, and currently work for their sister company, SoCalGas.)
These high voltage lines and systems have safety mechanisms built in that cut power to the high voltage lines when there is a power disruption. So, when they say severed, they mean they had sort of disconnected themselves from the grid for safety reasons. When the guy flipped the switch in Yuma, it caused a power surge that brought down both high voltage lines into San Diego. When those went down, San Onofre, also shut down for safety reasons.
Similar thing happened in the big outage in the Northeast a few winters back which caused that domino effect that took out power to 50 million people.
(In full disclosure, I had worked at SDG&E for almost 10 years, and currently work for their sister company, SoCalGas.)
Last edited: