Sensitive incipient inter‐turn fault detection algorithm for power transformers

This study presents a sensitive and online approach for transformer inter‐turn fault detection at the inception stage. The technique is based on computation and application of difference in positive sequence impedance and difference in negative sequence current of transformer. A new characteristic plot is developed for this purpose from the transformer nameplate details and test results. The settings of the proposed algorithm adapt online for on‐load tap changer operation. The proposed technique is verified through simulation, and results are experimentally validated on a specially designed 10 kVA transformer. The results suggest significant improvement in sensitivity for inter‐turn fault detection as compared with commercially available dual slope differential protection scheme.