| This paper deals with design improvements on graded insulation of power transformers using transient electric eld analysis and a visualization technique. The calculation method for transient electric eld analysis inside a power transformer impressed with impulse voltage is presented: Initially, the concentrated electric network for the power transformer is constructed by dividing transformer ...

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 ...

Transformers are normally designed and built for use at rated frequency and perfect sinusoidal load current. A non-linear load on a transformer leads to harmonic power losses which cause increased operational costs and additional heating in power system components. It leads to higher losses, early fatigue of insulation, premature failure and reduction of the useful life of the transformer. To p...

An audio transformer is used in a guitar amplifier to match the impedances of the power amplifier and a loudspeaker. It is important to understand the influence of the audio transformer on the overall sound quality for realistic tube amplifier emulation. This paper proposes to simulate the audio transformer using a wave digital filter model, which is based on the gyrator-capacitor analogy. The ...

The energizing of large power transformers has long been considered a critical event in the operation of an electric power system. When a transformer is energized by the utility, a typical inrush current could be as high as ten times its rated current. This could cause many problems from mechanical stress on transformer windings to harmonics injection, and system protection malfunction. There h...

A procedure for optimum design of a high-power, high-frequency transformer is PresentedThe Procedure is based on both electrical and thermal processes in the transformer and identifies a) the VA-rating of ferrite cores in relation to the operating frequency, , , ) the optimum flux density in the core, and c) the optimum current densities of the windings providing maximum transformer efficiency....

In this study, a modified disk-shaped multiple-output piezoelectric transformer operated at the fundamental radial vibration mode has been presented. A derived equivalent circuit for the multioutput piezoelectric transformer was used to analyze the performance. Two piezoelectric transformers, a symmetrically electroded piezoelectric transformer with dual outputs and an asymmetrically electroded...

This study adopted previous fault patterns, results of detection analysis, historical records and data, and experts’ experiences to establish fuzzy principles and estimate the failure probability index of components of a power transformer. Considering that actual parameters and limiting conditions of parameters may differ, this study used the standard data of IEC, IEEE, and CIGRE as condition p...