Search coil based transformer inter-turn fault detection

Detection of transformer inter-turn fault at early stage is essential for increasing life of transformer and avoiding economical impacts. This paper presents a novel approach to detect transformer inter-turn fault by search coil induced voltage analysis. A healthy winding is associated with symmetrical leakage flux pattern. With initiation of inter-turn fault it does not remain symmetrical and creates distorted leakage flux pattern. This distorted leakage flux linking with search coil induces voltage based on degree of symmetry of leakage flux. Analysis of this induced voltage can detect presence of fault and also predict its severity.