The Influence Of Temperature To The Frequency Response Of The Windings Of Power Transformer

The power transformer is the most important equipment in the power system network.The most critical aspect of a transformer that needs to be monitored is the mechanical condition of the windings.One of the best approaches to achieve this is by performing the Frequency Response Analysis(FRA).If any physical changes occur,it will affect the original response,which can be used to detect any abnormality.FRA signal contains an information about insulation condition as well.In thesis,an MTL(multi-conductor transmission line)model of power transformer winding has been developed and used for simulation the frequency response curve of winding under different insulation conditions.FRA curves in different conditions of winding:normal(healthy winding);radial deformed;under moisture content varies(1-7%);under temperature varies(from 20 to 80 ℃)have been simulated and discussed.Initially,a normal frequency response of MTL model deformation of winding has been simulated and analyzed in compassion with the radial deformed winding with buckling radius 30 mm.Then,the influence of moisture and temperature on insulation of transformer winding were investigated.Change in the moisture content or temperature mode of the transformer insulation will cause a change in the dielectric parameters.Therefore,to estimate the effect of moisture content,a dielectric response analysis is used.Thesis includes dielectric response models for impregnant pressboard,paper,and oil.These models required for estimating an effect of moisture and temperature varies on frequency response of power transformer winding.Change in moisture content is mostly affected as a shift in resonant frequencies of simulated frequency response curves.However,based on the obtained results,influence of temperature on the dielectric responses of impregnant paper and pressboard caused the slight damping of the resonance of winding frequency response.Proposed models of dielectric response of insulation with different moisture content and temperature range allows providing the results of winding condition using FRA curves analyzing.