Off-line signature evaluation for dqWPT hybrid technique based differential protection of power transformers

In this paper, an evaluation of signature performances for a hybrid dqWPT based differential protection technique for power transformers is carried out. The extracted signature, from the behavior of different types of transients in the power transformer, is tested and evaluated in order to provide a fast protection for power transformers. This algorithm permits the development of an efficient differential relay to detect internal faults that may occur in power transformers. Moreover, the algorithm is able to discriminate between magnetizing inrush currents and fault currents. Data for transformer transients are collected experimentally in the laboratory for different cases of normal and abnormal operating conditions. These cases include magnetizing inrush and faults at different loading conditions to test the efficacy of the extracted signatures.