Design and Simulation of Current Transformer Based on PCB Planar-Type of Air Core Coil

The stability and reliability of the power frequencycurrent measurement in the power system is an important meansto ensure the stable and reliable operation of the distributionnetwork. Because the traditional current transformer contains aniron core, its ferromagnetic effect is easy to cause linearsaturation and ferromagnetic resonance, and there are more andmore problems in insulation performance, volume and bandwidthresponse. Therefore, in view of the above problems, this paperdesigns a new type of current transformer based on PCB planar-type of air core coil for power frequency current measurement indistribution network. Firstly, the relationship between the currentof the transmission wire and its surrounding magnetic inductionis studied, and an air core coil sensor with an inverse seriesstructure is proposed. The working state of the sensor is analyzed, and the appropriate integrating circuit is selected to obtain theoptimal design scheme of the sensor. Secondly, the finite elementsimulation software is used to establish an air core coil model, andthe induced voltage of a single PCB air core coil is calculated, andthe anti-interference performance is simulated and analyzed. Finally, the amplitude-frequency characteristics, steady-state and dynamic response performance of the PCB air core coil are simulated. Simulation analysis verifies that the designed PCB air core coil transformer has a wide frequency band, can effectively resist the influence of external interference magnetic field, and has good transient response and steady-state response performance. It is suitable for current measurement of transmission conductors in distribution network, and meets the intelligent and automatic requirements of current measurement of power system in the future.