A NOVEL APPROACH TO SFRA (SWEEP FREQUENCY RESPONSE ANALYSIS) TEST ON ONLINE TRANSFORMER

Abstract: In this paper, a study of 6.6kV transformer with continuous disc type winding is implemented. the deformations in winding are explored by frequency response analysis (FRA) method. Presented circuit is developed on the basis of lumped parameter model. Series inductance, ground capacitance (shunt capacitance) and series capacitance are elements considered for analyzing transformer. The calculations were performed using the data sheet for the 6.6kV transformer design specification. To simulate the risk of winding failure, the parameter values were altered, resulting in a varied frequency range spectrum. The FRA simulation has a frequency range of 10 kHz to 2MHz. Transfer function (Vout/Vin) and trans-impedance (Vin/Iout) simulations were performed.
The MATLAB/Simulink software program is utilized for simulation and analysis. The bode plot command used to plot the magnitude of the equivalent circuit of the transformer. Simulations used to develop faulty and healthy circuits for the purpose of analysis. For measuring minor deviations within specified frequency bands, linear frequency scale used (varies from 10Hz-2MHz). This paper includes sweep frequency response analysis in the FRA. A simple offline SFRA tests have performed on the transformer, along with a description of the various features of winding problems. A basic online SFRA test is performed using the same transformer and presented using MATLAB/Simulink tools and routines.

Keywords: SFRA, FRA, HV, LV, MATLAB/Simulink, winding fault of transformer