A two stage model is used to model the high frequency transient behavior of two winding transformers. The assumed transformer model’s parameters are estimated using the maximum likelihood estimation technique and the Kalman filter based on the time response data. Simulations are carried out using the frequency response data generated based on an assumed transformer model. The transfer function ...

Conjugate heat transfer problem of a disc winding in a power transformer is studied using commercial CFD software. The study is done for oil flow, temperature distribution, hot spot location and temperature of the winding, for three different cases: first, no oil leakage past the top washer; second, partial leakage due to a 2 mm gap between the top oil guiding washer and cylindrical pressboard;...

A field-circuit method for simulation of transients in a single-phase, two-winding transformer has been given. The magnetic field excited by the winding currents has been analyzed, and integral parameters have been determined. Including the equivalent circuit parameters and the magnetic residual flux in the silicon steel core, the developed method has been implemented for the transitional state...

The internal faults of transformer can be identified by various techniques. The proposed technique is by the analysis of no-load current and harmonic contents present in it. The no-load current of transformer is non-sinusoidal for sinusoidal input voltage. And hence it contains harmonics in healthy condition of transformer. But if transformer has any internal fault then the no-load current magn...

The success of health monitoring and condition assessment of power transformers based on winding current signature analysis lies on proper extraction of features. The extraction of features in turn depends on appropriate signal processing methods. Fourier based signal analysis provides only frequency information and also suitable only for stationary signals. In this paper we present a combined ...

Frequency response analysis (FRA) is a sensitive ‎method established for testing the mechanical integrity of ‎transformers. However, interpretation of FRA signature still ‎needs expert opinions and there is no FRA interpretation code ‎generally accepted. Various mechanical faults with different ‎extents on power transformers are required to aid FRA ‎interpretation. To address this challenge, in...

With changing the parameters of layer winding in transformers, capacitive characteristic coefficient of winding will be changed. Since, impulse voltage distribution (IVD) along a winding is depended on this coefficient, so analyzing this coefficient is important in transformers. This paper study and analyze a transformer with layer winding and rectangular cross-section. In this study, the influ...

This research work is an initiative to characterize the thermal behavior of power transformers in presence of winding short circuit faults as one of the most important causes of failures in power transformers. The paper contributes for this matter by accurately estimating the excessive power losses and temperature rise due to winding short circuit faults, through a circuit-magnetic-thermal FEM ...

Identification and location of partial discharge (PD) source is an important diagnostic tool for reliable operation of transformer. In this paper, future template numerical interpretation techniques are proposed for location of PD pulse duration from 0.1 s to 5 s in transformer windings using sweep frequency response analysis (SFRA) principle. To analyze the efficacy of the proposed techniques ...

High-frequency loss in transformer windings using stranded wire is analyzed. A complete loss prediction method is presented. The interstrand resistivity, which is an important parameter to determine the power loss, is measured experimentally. The analytical model is solved to get an optimal pitch, which specifies the degree of twisting that results in minimum loss. A transformer using a strande...