Abstract: Based on the current coil taking device, a method to prevent the saturation of ferromagnetic core is proposed. The bypass discharge circuit is used to introduce excessive current flowing into the current transformer into the bypass circuit to consume, and the output power is used as the feedback value to adjust the switching tube in the bypass circuit. In this way, by controlling the output power, the transmission line achieves constant power output over a wide range of currents and prevents the magnetic core of the current transformer from reaching saturation. The 3D model of the current transformer is established according to the requirements of various aspects of the current transformer, and the 3D model is imported into Maxwell to conduct finite element simulation analysis of the current transformer itself, so as to obtain the internal parameters of the current transformer. Then the finite element analysis of the current transformer model is imported into ANSYS to form a power taking circuit with the external circuit for co-simulation. The power taking capability of current transformer is verified by simulation results. The optimization part of current transformer taking power is added, and the equivalent impedance of the primary transmission line increased through the secondary side resonance of the current transformer. Considering the saturation problem of the magnetic core of the current transformer, bypass discharge circuit is adopted to bypass the excessive current to the primary side of the current transformer and return to the transmission line.