“IIRC Back in the 90’s there was some experimentation with High voltage DC transmission lines. One of the problems was that they did not get hot enough to keep ice off them.”
The same amount of heat is generated in a wire with dc as with ac.
Been a while since I studied any of this but as I recall the capacitive correction for AC lines increases line current. I also think that given equal size wires AC will see greater impedance due to skin effect. Finally I believe the DC transmission is done at higher voltages than AC which decreases the line current and thus the heat losses.
My original statement comes from something I read in college and I think that engineers used to sizing cable for AC oversized the cable in DC experiments and thus had icing problems.
Actually, the heat would be different in a pure DC system -— no loss to reactivity. However, it appears there is a direct relationship between DC current and ice formation, Google is your friend. But I did find this at the top of the search results which looked interesting:
http://www.sciencedirect.com/science/article/pii/0165232X81900276