Study of Transformer Winding Parameters as Deformation Diagnostics Techniques Using FRA Measurement

Transformer is one of the paramount devices in the utility grids. Though a static device, its reliable functioning is an outcome of electrical, mechanical, thermal and chemical subsystems. During normal operating conditions the transformer winding suffers from internal axial and radial forces due to the flow of current in the windings. The transient condition challenges mechanical integrity of the winding significantly. The mechanical integrity of the winding plays an important role in ensuring reliability of the equipment. For this reason, advanced techniques have been developed in recent years for condition monitoring of transformer. FRA (Frequency Response Analysis) has gained worldwide popularity as the non-intrusive test technique. Literature suggests that the FRA can be used to detect transformer winding displacements [1]. This paper presents a simulation study of analysis of equivalent circuit of transformer winding using state space approach[1][2]. It is shown that the FRA measurement on basic electrical circuits, which can be extended for studying the mechanical integrity of a transformer after short circuit fault, transportation etc. Keywords—Series capacitance, shunt capacitance, Frequency Response Analysis, Signatures, axial displacements, radial deformation, and model based comparison.