Core Saturation Detection and Calibration of a Current Probe for Fast Transient Currents

Low-frequency distortion caused by core saturation has a great effect on the performance of magnetic core Rogowski coils (RCs). The maximum current-time product can be used to determine the reliable operating range of such a coil. This paper presents a core saturation detection and calibration method of RC with a Mn-Zn ferrite core for fast transient currents. To determine the maximum current-time product, the parameters of the core material are obtained from the dynamic initial B -H curves under fast current excitations, and the maximum current-time product of the probe is derived based on the magnetic path model. The low-frequency distortion phenomenon of core saturation and the calibration result of the maximum current-time product are analyzed and verified in the experiment. It shows that the probe has a good amplitude-frequency response in the range from 5 Hz to 2 MHz, with the sensitivity of 1.44 V/kA.