Electromagnetic energy harvester for atmospheric sensors on overhead power distribution lines

In this paper we present a small, credit-card sized, and low-cost electromagnetic energy harvester that couples energy from one conductor of an overhead power distribution line. We use a rectangular coil, placed near the power line without encircling it, to extract electrical power from the time-varying magnetic field. The addition of a U-shaped electrical steel sheet (a high-permeability material typically used in transformers) near the coil significantly increases the magnetic flux through the coil and consequently raises the output power. Experiments have shown that the harvester with an optimal load resistance obtains 230 mW (AC) when the power-line conductor current is 50 Arms. The energy harvester is able to power a wireless gas sensor board having a carbon monoxide and an ozone sensors at 10 Arms.