Conditioning monitoring of transformer using Sweep frequency response for winding deformation

Monitoring the health of power transformer is important for the reliability of electrical power supply. Sweep Frequency Response Analysis is a powerful tool for analysing transformer health and mechanical integrity is used to check the eventual change in the internal geometry of the active parts of the transformer, displacements or deformations. The main causes of such as the presence of external short-circuit. These faults may result in complete rupture of insulation which will result in complete damage of the winding. A benchmark winding is considered which has already been validated for experimental studies. The winding is modelled using finite element method (FEM) based software and parameters such as capacitance and inductance are calculated for 10 section healthy helical coil, by these parameter values, SFRA plots are obtained which are a set of reference for deformation analysis. The winding is modelled as radially and axially deformed coils using FEM software. The deformation is carried at five consecutive sections; purpose of doing so to find the location of deformation corresponding to a similar deformation in an actual transformer. The advantage of the FEM modelling is, we can deform the sections as desired unlike in an actual case and obtain the fingerprint graphs from the modified parameter values. The SFRA plots are obtained for the deformations at five sections for axial and radial deformations. A comparison is carried between the SFRA plots for deformed cases with reference set & deviations observed are in resonant frequencies & peak current magnitude. So the type and location of deformation can be found corresponding to a similar deformation in an actual power transformer.