Analysis of Distribution Transformer Performance under Non-linear Balanced Load Conditions and Its Remedial Measures

In recent years there has been very extensive use of power electronic devices, which result in harmonic proliferation in the power distribution system. In this paper, as per IEEE C 57.110 standards, procedure to calculate total loss in the distribution transformer under non-linear distortion environment is proposed. The power factor capacitor performance under non-linear load conditions is also analyzed. The relation of total current harmonic distortion in the distribution system with load power factor, transformer losses, efficiency and maximum current delivered is also analyzed. The mitigation methods are proposed to minimize the non-linear load impact on the distribution transformer performance. Instead of K-factor transformer approach, a passive harmonic filter method is developed based on higher savings in energy losses. The simulation studies, are performed using Math works MATLAB 7.0.1 for distribution system at 11/0.440 kV, 200 kVA distribution transformer under non-linear balanced load conditions. It is observed that the power factor capacitor bank acts as a source of harmonic under the nonlinear load conditions in the presence of passive filters. Keywords— Harmonic Proliferation, k-Factor, Non-linear Load, Power Factor, Mitigation.