Finite-Impulse- Response Modeling of Voltage Instrument Transformers Applicable for Fast Front Transients Simulations

This paper presents a method for Finite-Impulse-Response (FIR) modeling of voltage instrument transformers. The method is based on Wiener filtering and measurement of the transformer response in the frequency domain using a low frequency network analyzer. The proposed method allows, through digital filtering operation, an accurate simulation of the transformer response to transient excitation. Furthermore, the proposed approach to the modeling of the system function allows unequal spacing of the frequency samples. The linearity of the transformer is analyzed applying the Fourier analysis and different waveforms of the primary voltage, and methods for the model order selection, based on the generalized information criterion, are discussed and applied. The theoretical analysis is confirmed with measurements in time domain, using the recurrent surge generator.