Review of Protection Approaches for Discrimination between Internal Fault and Inrush Current in Electric Power Transformers

Abstract

This paper presents a review of different protection approaches used with transformer differential protection to discriminate between internal fault current, magnetizing inrush current during energization, magnetizing inrush current. These approaches include harmonic restraint, voltage and flux restraints, the inductance based method and pattern recognition. The pattern recognition approach has mainly been designed using artificial intelligence (neural networks, fuzzy logic), wavelet transforms and hybrid techniques.