[Blue Bomber Man]

High voltage lines cannot be buried feasibly. A transmission line at 60k Volts has an enormous potential to jump a large distance. That is why the lines are seperated by 20-30ft of air (which itself is an incredible insulator) I dont know how they would compare to say insulating the wire and burying it, but I imagine you would need a massive insulator.

An underground cable would probably be not much safer then an above ground cable to a terrorist, it would still be easy to locate, and wouldnt be hard to disrupt with a bomb. Additionally it would be much more difficult to repair.

I've read the article someone referenced earlier from SciAm about high powererd trans lines, but I think that is not as nearly as viable as a decentralized power with a smart grid tech.