Development of reference SFRA plot of transformer at design stage using high frequency modelling

Abstract

Any deformation or displacement in the transformer winding can cause change in the circuit parameters and frequency response. The changes can be detected using Sweep Frequency Response Analysis (SFRA). For the detection of the changes, SFRA needs a reference which is generated during commissioning of the transformer. The reference generated can be used by the same SFRA kit. But SFRA kit keeps on updating. If the transformer needs to have SFRA tests after 20 years of its commissioning, the SFRA kit might be updated and hence the old reference is unable to be used. SFRA response at design stage would remove this bottleneck which can be used for any SFRA kit. In this paper a high frequency simulated model of a 10 MVA transformer is developed based on lumped parameter representation for SFRA interpretation. SFRA plot of the model (simulated data) can be compared with the experimental SFRA plot (measured data) of the transformer and it has been found that the same can be used as a reference.