새로운 변압기 보호용 디지털 계전 알고리즘

A New Digital Relaying Algorithm for Transformer Protection

This paper presents a new digital relaying algorithm for protection of a two winding power transformer. The proposed algorithm calculates mutual flux linkages of primary and secondary windings from the currents and voltages of primary and secondary windings. The mutual flux linkage ratio of primary and secondary windings is equal to the turn ratio in case of the steady state and magnetic inrush. On the other hand, the ratio is different from the turn ratio in case of internal winding faults. The algorithm does not require B-H curve. The results of various tests are satisfactory.