Detecting and removing minor faults in power transformer winding is essential because minor
faults may develop and lead to major faults and finally irretrievable damages occur. In this paper in order to
detect the position of short-circuit in the winding, frequency response of the input impedance of a power
transformer is analyzed. Common short-circuits are categorized and the results are compared, then the
behavior of frequency response due to disk-disk short-circuit is investigated. To increase the accuracy of
analysis, innovative approach in finite element analysis is offered. This approach termed Electromagnetic
quasi-static considers both magnetic and electric characteristics of power transformer. Simulation is
fulfilled by interconnecting between finite element analysis and circuit-based model for employing shortcircuit.