Power supply is the key to ensure stable operation of on-line monitoring device of high-voltage transmission line. In this paper

a kind of energy extraction power supply based on the high-voltage electric field induction energy extraction technology is proposed

and its power circuit and control circuit are analyzed and designed respectively. The displacement current generated by the inductor pole plate as the input of the energy extraction power supply directly determines the input power of the energy extraction power supply. The influence of the size of the inductor pole plate on the displacement current is investigated by using the Comsol software

the size of the inductor pole plate is determined and compared with actually measured data so to verify the correctness of the simulation. Based on this

a set of video monitoring device is developed in the paper

which realizes the self-energy extraction of the device through the inductor pole plate and the energy extraction power supply

shoots the video of the transmission line and the surrounding environment and sends it to the remote terminal. Finally

it is experimentally determined that when the video monitoring device is applied at voltage level at 110 kV

the duration of a single video received by the remote terminal is 2.2 min

and the video interval is 54.9 min.