There are attempts, sure. But with CIP in full swing across utilities it is impossible to get to SCADA networks unless your are strictly granted access. Only a saboteur that already works for a utility could cause havoc. The SCADA network is highly isolated. It would just be easier to have a four man team shoot up some of the heavy transformers (A test run was done in L.A. in 2015. The attackers had lots of time to shoot at the transformer. They also knew exactly how to disable alarms/alerts buy cutting the right fiber runs). That is where we are exposed.
There are 9 substations around the region that if all taken out simultaneously would take down the entire NE grid. Substations like the one in LA are basically totally accessible so it could be done with firepower but cyber hacking is likely the way it will happen. Our power grid is very vulnerable. Anytime somebody tells you it cannot be hacked it just hasn’t happened yet.