A nonlinear model for the estimation of the primary current in current transformers

The measurement of the current in industrial electrical devices is often carried out by resorting to the use of current transformers. The reliability of these devices is compromised when the measured current is higher than the nominal value, due to the saturation and hysteresis effects of the magnetic core. In this paper, a nonlinear model of the current transformer is identified by means of a separable least squares technique. This model is successfully employed for the estimation of the primary current starting from experimental measures of the distorted current.