Transformer inter-turn winding fault detection based on no-load active power loss and reactive power

An inter-turn fault in a transformer can cause severe damage to transformer windings if not detected quickly. In this paper, the fault diagnosis is discussed by examining the no-load active power loss (NLAPL) and no-load reactive power (NLRP) of the transformer. Two indices, Total harmonic distortion of active power (THDAP) and Total harmonic distortion of reactive power (THDRP), based on odd harmonic components of NLAPL and NLRP, are proposed. To validate the obtained results, the acquired outcomes of tests on a physical device are compared with the results of the finite element analysis. To do this, three-dimensional model of a single-phase transformer is simulated in the transient mode using ANSYS MAXWELL 17.02. Results show that in the presence of an inter-turn short circuit fault on the transformer high voltage (HV) windings, the low voltage side current and NLAPL increase while the variation in NLRP is very small. In addition, from the transient analysis point of view, it becomes clear that THDAP and THDRP are reduced in the presence of an inter-turn fault.