Inter-Turn Short-Circuit Detection Through Differential Admittance Monitoring in Transformers

Early detection of inter-turn short-circuits (ITSCs) in power transformers is essential for ensuring the safe and reliable operation of electrical power systems. Therefore, it is necessary to develop efficient detection strategies. In this article, a strategy for detecting ITSCs of a transformer based on monitoring electrical variables is proposed. An indicator for fault diagnosis obtained from the calculation of differential admittances is proposed. Experimental tests on a 5-kVA transformer validate the proposal. The strategy is sensitive to faults involving 1% of the winding turns with rated current in the fault loop. Besides, it is shown that the fault detection strategy is immune to changes in the load state, undervoltage, load or voltage unbalance, and transformer vector group.