Here’s a thought.
If the Ukraine wanted to stop sending power to the Crimea, all they had to do was stop sending it. No demolition of expensive transmission equipment would be needed.
If Russia wanted to stop Ukraine sending power to Crimea in a false flag attack, they would not have gone into Kiev or wherever to terminate the transmission. They only needed to blow up transmission equipment and walk away.
Kiev needed a “cut out” in the form of Right Sector and associated crazies to fell the transmission lines without having the responsibility fall directly on the junta. Just like Kiev is sanctioning the “food blockade” of Crimea by not ending it.