Harmonics analysis in autotransformers ferroresonance circuit

This paper studies the effect of iron core saturation characteristic degree on the occurrence of harmonic modes in an autotransformer. The selected transformer for study has a rating of 50 MVA, 635.1 kV. The magnetization characteristic index of the autotransformer is chosen with q=5, 7, 11. The linear core loss is considered for transformer core. The MATLAB software is used for analyzing existence harmonic modes in the proposed power system. It is shown high order harmonics are occurred when degree of core nonlinearity is gone from 5 to 11.