Cables are separated regularly on long stretches of cable. I've seen separators on all kinds of power cables, so I doubt shorting out would be a serious problem

Cables are separated regularly on long stretches of cable. I've seen separators on all kinds of power cables, so I doubt shorting out would be a serious problem, however the cables reaching a harmonic might be a problem. Suspension bridges can be brought down by wind, so when you start attaching multiple cables into one unified body with high drag, you're going to begin risking a wind-induced harmonic taking out your power lines. It's a good idea, I doubt they'll replace power plants, but they're likely to be far more useful and practical than their windturbine brethren due to the sheer fact that they may be able to make the construction of power cables profitable in themselves. Instead of costing for maintenance and the average 7% drain of long distance power cables, using this style of wind turbine could turn existing power cables into profit or at least give them a break-even potential.