4 ms·
My favorite power outage story is the 1998 San Francisco / Peninsula outage. Contractors were working on a substation so they disconnected the 115 kV line and s
by kens 6y ago
My favorite power outage story is the 1998 San Francisco / Peninsula outage. Contractors were working on a substation so they disconnected the 115 kV line and strapped it to ground to protect against stray current. When they were done, they powered up the line. Unfortunately, they forgot to remove the ground straps.
It turns out that the power grid doesn't like it when you connect 115 kV directly to ground. By the time the ground straps vaporized, the fluctuations caused all the generators in San Francisco to go offline, cutting power to a million people.
Bringing the power grid back up took hours. Among other problems, they discovered that the SCADA modems in several substations ran off AC without backup, so they couldn't access the substations remotely when the power was down. Oops.
https://www.nerc.com/pa/rrm/ea/System%20Disturbance%20Reports%20DL/1998SystemDisturbance.pdf https://www.nerc.com/pa/rrm/ea/System%20Disturbance%20Report...