When I was born in 1958, I’m not even sure Niagara-Mohawk (the power company for the area of New York State where I grew up) owned a computer.
Computers became popular in the 1960’s. I remember checking the price of IBM stock after my father bought his weekly copy of Barron’s.
It isn't just protection from computers. It is physical protection of the transformers themselves. There are critical transformers to the power grid whose only protection is a chain link fence. These should be protected by a reinforced concrete shell surrounding it. As things stand now, they can be destroyed by a high caliber round from a rifle. These transformers are only made in Germany and take up to 3 years to construct. The US is out of luck if these are taken out.
As an aside, I live in Taiwan. Yesterday, my phone went off with a Presidential Alert message ( it was in Chinese so I didn't know what it said ). Two seconds later, all the power went out. My first though was the Chinese were invading, but I didn't hear any air raid sirens. So I tuned into the English radio station ( ICRT ) to see what was going on. When I tuned in they were playin a song - The Final Countdown :-) Turns out 2 of the 4 generators at a station went out ( blamed it on a computer problem ). 6 million were without power from 3 PM to 9PM ( the had rolling blackouts - power for an hour, power off for an hour )