Transformer inrush currents are highmagnitude, harmonic-rich currents generated when transformer cores are driven into saturation during energization. These currents have undesirable effects, including potential damage or loss-of-life to the transformer, protective relay misoperation, and reduced power quality on the system. Controlled transformer switching can potentially eliminate these trans...

Geomagnetically Induced Currents (GIC) are supposed to be a threat to power transformers worldwide. Recent surveys show correlation between solar storm activities, the cause of GIC, and transformers failing within a relatively short time period. The scope of this contribution is to create and investigate a laboratory setup emulating GIC effects by injecting DC currents into a three phase power ...

The study introduces the detailed sequence of operations necessary to determine the selfand mutual inductances of power transformers from numerically simulated open-circuit and bucking experiments. Parameters of a welding style transformer are compared to those of a normal step-down transformer of equivalent ratings. The investigation identifies the different patterns of magnetic flux circulati...

-Protective systems require a faithful reproduction of primary current on the Current Transformer (CT) secondary side. Saturation is a common problem in a steel core CT. Saturation problem causes dreadful effects in the protection systems. This paper presents a simple solution towards detection and compensation of current transformer saturation problems. This paper describes a method in which C...

The paper proposes an innovative design to develop a system based on AVR micro controller that is used for monitoring the voltage, current and temperature of a distribution transformer in a substation and to protect the system from the rise in mentioned parameters. Providing the protection to the distribution transformer can be accomplished by shutting down the entire unit with the aid of the R...

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...

| 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 ...