The WSJ article is behind a paywall, here's one that isn't: http://www.nbcbayarea.com/news/local/Ter...243731551.html.

It appears that this attack happened in April 2013. Nobody lost power, and nobody was arrested.

If it's difficult to protect electrical substations from this sort of attack, it should be fairly easy to put together a detection system and a response plan. Would that stop a large-scale planned attack against critical infrastructure? No. But it would likely allow for single actors to be caught and incarcerated.