Bit of an oversimplification, but I think it was a human error assisted by bad design. An engineer set the "state estimator" to manual mode at 12:40 pm, then a

Bit of an oversimplification, but I think it was a human error assisted by bad design. An engineer set the "state estimator" to manual mode at 12:40 pm, then at 1:30 pm went to lunch forgetting to put it back on auto. Half an hour later, a grounded wire set off the first outage and due to the system reporting bad information, a cascade occurred. They had launched the new power model just a couple of months prior, but I don't think it was a software glitch. For a few more details, see https://news.ycombinator.com/item?id=12476001 https://news.ycombinator.com/item?id=12476001 and for the full report (238-page PDF) see https://www.energy.gov/sites/prod/files/oeprod/DocumentsandMedia/BlackoutFinal-Web.pdf https://www.energy.gov/sites/prod/files/oeprod/DocumentsandM...