The sensing part of the electronic current transformer is composed of an integrating circuit, an amplifying circuit, an A/D conversion circuit and the like, and these lines are completely electronic circuits. Therefore, the high-voltage side of the electronic current transformer must have a stable power supply to these electronic components line. It is a difficult and important point in the circuit power supply problem of electronic current transformer designers. A stable power supply solution is an important condition for ensuring stable operation of the electronic current transformer. In this paper, based on the high-voltage energy extraction of the energizing coil and the lithium-ion battery combined power supply scheme, according to the established simulation model of the energy-carrying coil, the optimal design and simulation of the optimal number of energizing coils are carried out. The feasibility and effectiveness of the scheme are verified by simulation experiments on the energy-carrying coil and the power supply system.