An Instantaneous Measurement Based Transformer Protection Scheme

A transformer protection scheme using fault component computed from instantaneous measurement values is proposed in this paper. The algorithm utilizes reactive power directional elements computed from the received IEC 61850-9-2 sampled values, and uses the ratio of active and reactive currents to determine an inrush condition. A transformer fault is declaimed if the directional elements from all transformer terminals seen the fault in its forward direction. Extensive simulation tests show that the proposed algorithm is sensitive to detecting faults, and is able to distinguish faults internal or external to the protected transformer zone, and to discriminate a fault from inrush conditions.