So in the past 12 weeks, there have been…
-multiple attacks via firearms on power substations in NC and SC (just this week).
-6 attacks via firearms, hand tools, arson, & metal chains at power substations in WA and OR.
-6 attacks via firearms on substations in FL in a single 12-day stretch in September.

This style of attack on power substations has been laid out in detail in multiple accelerationist documents, including an “accelerationist handbook” that circulated on Telegram this summer.

In July, DHS warned about an “accelerationist handbook” circulating on extremist Telegram channels that explicitly called for potential attackers to bypass mass shootings in favor of causing chaotic blackouts by attacking the power grid, which the handbook referred to as a “sitting duck”. Neo-Nazi accelerationists want to use this to start a race war; they claim that with an extended blackout "all hell will break lose [sic]" and white supremacists would be poised to take control.
In February, several white supremacist accelerationists pleaded guilty to conspiring to attack regional power substations in an effort to cause widespread power outages and civil unrest, which they hoped to exploit to start a race war.
https://www.justice.gov/opa/pr/three-men-plead-guilty-conspiring-provide-material-support-plot-attack-power-grids-united
Three Men Plead Guilty to Conspiring to Provide Material Support to a Plot to Attack Power Grids in the United States

Three men pleaded guilty today to crimes related to a scheme to attack power grids in the United States in furtherance of white supremacist ideology.

It’s not clear yet who is behind all of these attacks, but an internal federal memo said the aim of the attacks on power substations in WA & OR is “violent anti-government criminal activity.”
https://www.koin.com/news/oregon/memo-oregon-washington-substations-intentionally-attacked/
In NC, investigators are looking into “online conspiracy theories” as a possible motive. They described the unknown attacker(s) as someone who “knew what they were doing.”
https://www.nbcnews.com/news/amp/rcna60834
Memo: Oregon, Washington substations intentionally attacked

“Power companies in Oregon and Washington have reported physical attacks on substations using handtools, arson, firearms and metal chains possibly in response to an online call for attacks on…

KOIN.com
@rvawonk it seems like I recall a case of similar that were also attacks on the electrical substations. It occurred in New England (I think around 2013). In that case they were probing the electrical grid for vulnerabilities at that time. (And I’m sure before.) Does anyone else remember more on this case?
@unsinkableme this is probably what you’re thinking of — a 2013 sniper attack on substations in California. It did millions in damages and the suspects were never caught.
https://www.wsj.com/articles/SB10001424052702304851104579359141941621778
Assault on California Power Station Raises Alarm on Potential for Terrorism

April Sniper Attack Knocked Out Substation, Raises Concern for Country's Power Grid

The Wall Street Journal