A novel energy obtaining system for on-line monitoring devices of transmission line

The research of the energy source of online condition monitoring devices for transmission line is a current interest. An energy capture system using both current transformer (CT) and lithium batteries is proposed in this paper. Through this system, the CT with variable turns transmits energy of transmission lines to devices and lithium batteries. The latter works only if line current is inadequate. In addition, the turns radio is 300:1 when line current is under 400A. This ensures that secondary current can still supply energy. On the contrary, for preventing high secondary current, it is adjusted to 450:1. As a result, the output power can be constant 2.5W when line current ranges from 0A to 600A. Combined with the advantages of both CT energy supply and lithium battery energy supply, the system is compact, lightweight and easy to be integrated and expanded.