Electric field energy harvesting for on-line condition-monitoring device installed on high-voltage transmission tower

A method for powering an on-line condition-monitoring device installed on a high-voltage transmission tower is presented. The technique uses the harvesting plate and a transformer both installed away from the transmission line to harvest the electric field energy. The circuit model of the method is analysed and the power equation given. The method has been experimentally validated. When the stray capacitance is 40 pF, about 645 mW was obtained with the load resistance 0.9 kΩ once 50 kV AC was applied on the electric field generator.