Fuzzy Logic based Controller for Power Transformer Protection

Abstract

Power transformers are imperative elements of power system. So it is substantial to evade
any mal-operation of required protective system. For many years, differential protection has
been used as the primary protection of power systems. It comprises the differential relay,
which operate for all internal fault types of power transformer and block due to inrush
current. The major disadvantage of the branch of differential protection relays, its potential
malfunction resulting from transient inrush current that flows when the transformer is
energized. This paper presents a novel technique of relaying algorithm which enhances the
fault detection methodology of the orthodox techniques by using fuzzy logic. The proposed
relaying technique depends on the principle of harmonic-current restraint. In this method the
magnetizing-inrush current is categorized by large 2
nd harmonic contents.