This is pretty interesting to me. Very long article about different ways that power grid has been infiltrated, and ways that has been used to shut it down/disrupt it in different ways. Has a "bad Russian" political slant, but pretty fascinating how they were trying out different techniques on compromised systems.
tl;dr Over the past few years, various Ukraine power companies have experienced shut-offs believed to be caused by Russian hackers. All the systems are initially compromised using a variety of social engineering and other technical means. They are then "parked" until the disruptors decide to target a particular system. Each systems has been targeted in a different way for the final attack, disruption/takeover of command structures, etc. followed by things like a hard drive wipe or reflashing the bios in computer connected power switches to render them useless.
https://www.wired.com/story/russian-hac ... k-ukraine/