Design a circuit to collect (harvest or couple) AC power from the EMFs generated by overhead 3 phase AC electric transmission lines/circuits in order to power a remote, autonomous, 30 W field computer and sensor system. Such systems are located at the periphery of high-voltage transmission line ROWs (Rights Of Way). Minimum distance to the overhead phase conductors is ~ 20 meters. Power harvesting/coupling mechanism and design can be based on AC Magnetics (induction) or AC Electrostatics; I have significant experience in sensing and in obtaining power using AC Magnetic Induction, and would prefer an AC Electrostatic Approach. A DC Output is desired, but low-voltage (<220 Vac) could be used. High-voltage overhead transmission lines/circuits range from 69 - 765 kV and, typically, carry 100 - 1000 A. Initial work should target 500 kV with a 500 A load.