Investigation on Anti-interference of Rogowski Coil Current Transformers in Smart Substations

The Rogowski coil current transformer is typically influenced by the high -frequency transient current generated during switching operations or shortcircuit fault. This paper investigated the mass change process in a Rogow ski coil transformer (differential, filtering, sampling, and integration) and analyzed the mechanism of the abnormal waveform generated in the transformer. Results showed that appropriate configuration of a low-pass filter placed before the collector reduced the amplitude of the high frequency component in the signal, resulting in attenuated amplitude of frequency components after aliasing. The filter also inhibited abnormal waveforms by increasing the sampling frequency of the sampler. Simulation results showed that the use of a fourth order Bessel filter to suppress high frequency signals and increase sampling rate to 100kHz is feasible and effective. The approach proposed in this study is shown to improve the operational reliability of Rogowski coil transformers.