There was a lot of talk a few years ago about the Stuxnet virus and how it ended up infecting a few important things in Iran. Cyberwarfare has been alive and well for some years, which art includes the countermeasures and counter-countermeasures similar to what was developed in the ESM, ECM, and ECCM capabilities over the past 50 to 60 years.
The trick in this art is to get in and out, do some damage, but leave no footprints. One could argue that the Stuxnet attempt didn't quite achieve that standard. A successful disruption effort would achieve a sort of "Ninjutsu of cyberwarfare," which leaves the culprit untracked, and/or leaves deliberate bits of misdirection to lead the victim of the attack looking elsewhere for the source of intrusion.
It's been a few years since I was involved in such things. I can only guess at how the art has progressed. Given how many nations are tossing brainpower into this arena of conflict and skullduggery, I'll guess that it has advanced by at least an order of magnitude.
Since I don't know how the Turkish electrical grid is constructed and deployed, it would be difficult to estimate how vulnerable it is to such interference. Where the critical nodes are would be where to look, what failure modes were, and how quickly they could be restored.
I don't discount the PM's concerns / fears that something got into the system deliberately, since all sorts of dirty work goes on in cyberspace every day. I do agree that
Fox3's position and Wanderoo's estimate are where to bet unless someone uncovers evidence of interference / disruption by an outside party.