Three-Phase four-wire distribution systems are facing severe power quality problems such as poor voltage regulation, high reactive power and harmonics current burden, load unbalancing, excessive neutral current, etc.This creates excessive neutral current both of fundamental and harmonic frequency and the neutral conductor gets overloaded. By integrating phase shifting into an extremely low zero...

A new integrated magnetic full wave dc/dc converter1 that provides flexible transformer design by incorporating an independent output inductor winding is introduced. The transformer is implemented on a traditional three-leg magnetic core. The inductor winding can be separately designed to control the output current ripple. The cross-sectional area of the inductor core leg can be reduced dramati...

This paper proposes a transformer-assisted pulsewidth-modulation zero-voltage-switching neutral-pointclamped (NPC) inverter. With the assistance of a transformer-assisted small-rating lossless auxiliary circuit, the main switches work with zero-voltage switching without suffering from any voltage/current spikes, under simple explicit control. The technique allows for higher operating frequency ...

The Mason crossed-field circuit model is generalized to simulate apodized interdigital transducers without channel division. The apodized transducer model is based on the transmission line model, and the artificial transformer with different voltage and current coupling ratios is used to independently obtain the transfer function and radiation admittance. In addition, a heuristic expression for...

Energization of a transformer results in sudden flow of current which is an effect of core magnetization. This current will be dominated by the presence of second harmonic, which in turn is used to segregate fault and inrush current, thus guaranteeing proper operation of the relay. This additional security in the relay sometimes obstructs or delays differential protection in a specific scenario...

In this paper, a combined neural network and an evolutionary programming scheme is proposed to improve the quality of wound core distribution transformers in an industrial environment by exploiting information derived from both the construction and transformer design phase. In particular, the neural network architecture is responsible for predicting transformer iron losses prior to their assemb...

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 ...

proper operations of transformer have several issues such as; preventing of unscheduled removal’s, increasing of reliability and continues supply of consumer demand. this result would be obtained that load and harmonic orders of sensitivity transformer at intervals appropriate for next hours and days is predicted to by selecting optimal utilization coefficient, reduction life of transformer is ...

Measuring the current in the neutral-grounding resistor is needed for monitoring resistance-grounded three phase transformers. This current is limited to hundreds of amperes in case of a fault, and are almost negligible otherwise. The current transformer that senses the current must be rated for the fault conditions, thus it is difficult to obtain a precise measurement of the current when there...

The principle object of this paper is to offer a modified design of Rogowski coil based on its frequency response. The improvement of the integrator circuit for nullifying the phase difference between the waveforms of the measured-current and the corresponding terminal voltage is a further object of this investigation. This paper addresses an accurate, yet more efficient measuring and protect...