The high frequency characteristic of wideband Rogowski coil with asymmetric windings

Rogowski coil is widely used to measure Partial discharge current pulses on electric power apparatus. Recently, Rogowski coil current sensors with wide frequency band became the tendency. In high frequency range, the Rogowski coils often appear resonance. The reason is not quite clear. In this paper the authors studied the high frequency characteristic of Rogowski coils by simulation and experiments to find out the influence of asymmetric windings. The authors made simulation of Rogowski coil based on distributed parameter model, including symmetric coils and asymmetric coils, and measured the magnitude characteristic of the transfer impedance of the coils. All of the research results tell us that the asymmetric windings can bring resonance to the coil at high frequency.