Ukraine to probe suspected Russian cyber attack on grid

A power company in western Ukraine said on Dec. 23 that a swath of the area it serves had been left without energy, including the regional capital Ivano-Frankivsk, due to "interference" in the work of the system.

It might be a cyber attack, it might be a bad infrastructure, it might be a human error...

It is much easier to hack the grid, than to proove that a blackout resulted from a computer attack.

http://www.reuters.com/article/us-ukraine-crisis-malware-idUSKBN0UE0ZZ20151231