An Interturn Short-Circuit Fault Diagnosis Method in Distribution Transformer Based on Three-phase Magnetizing Admittance Ratio

When the winding of distribution transformer occurs slight interturn short-circuit fault (ISCF), the variations of electric parameters are tiny and cannot be used as the sensitive characteristics of fault. A diagnosis method of incipient ISCF of distribution transformer based on three-phase magnetizing admittance ratio is presented. Firstly, the mathematical models of transformer under healthy and fault conditions are presented. Then, a new vector is constructed by using the three-phase magnetizing admittance ratio as the fault indicator. Finally, the simulation results show that the ISCF diagnosis method can not only detect the ISCF effectively, but also accurately identify the fault phase.