High Frequency Modeling of Transformer Using Black Box Frequency Response Analysis

Lightning Surges consequently induce high frequency overvoltage to transformers. Therefore, it is alluring to study the transfer voltage of lightning surges from primary to secondary side of transformer. Keeping in mind the end goal to do lead this review, high frequency Siemens power transformer of rating 25KVA, 25KV/400V is to be examined. In this paper, an advanced and modified high frequency model of transformer is presented for protection of load against lightning transients. Suggested model is modified form of N.A Sabiha model and based on black box, two ports four terminal network theory. For No load condition, Transformer parameters are calculated on two resonance frequencies of 450 KHz &1 MHz using fast Fourier transform. Matlab/Simulink is used for simulation analysis. Both Time and frequency domain validate the accuracy. Resemblance between the measured and calculated results confirms the precision of proposed model when an impulse of 1.2/50µs is applied to transformer terminals.