This paper presents a transformer less ac/dc converter which can be used in voltages between 90230 Vrms. Instead of a transformer, this topology consists of a buck dc/dc converter and a buck boost dc/dc converter. By the absence of transformer, reduce the complexity of converter and it is cost effective. Buck dc/dc converter keeps o/p voltage below the line voltage; limit the leakage current. B...

Ferroresonance is a highly destructive power quality phenomenon caused by complex oscillations generated by nonlinear magnetizing inductances in ferromagnetic materials and capacitive elements in power systems. In an effort to better understand ferroresonance and predict bifurcations and responses, an improved nonlinear transformer model for dynamic and steady-state operating conditions is deve...

A new topology of unified power quality conditioner (UPQC) is proposed for different power quality (PQ) improvement in a three-phase four-wire (3P-4W) distribution system. For neutral current mitigation, a star-hexagon transformer is connected in shunt near the load along with three-leg voltage source inverters (VSIs) based UPQC. For the mitigation of source neutral current, the uses of passive...

This paper describes role of UPQC as applied to a 3P4W system to improve PQ. The Forth wire of 3P4W system is developed by means of neutral of series transformer. Neutral current which flows through neutral terminal of transformer is removed with the help of 4 leg voltage source inverter (VSI) topology for shunt part. The series transformer neutral will have 0 potential in all conditions of ope...

Abstract: Transmission-line transformers are circuits useful for microwave impedance matching applications due to their broad operating bandwidth. Multimode feed network is composed of two substructures, which are constituted by the transmission-line transformer. Beginning with the broadband transmission-line transformer with 4:1 impedance transformation, supposing the currents on the two lines...

Power transformers are among the most important and expensive equipments in the electric power systems. Consequently the transformer protection is an essential part of the system protection. This paper presents a new method for locating transformer winding faults such as turn-to-turn, turn-to-core, turn-totransformer body, turn-to-earth, and high voltage winding to low voltage winding. In this ...

This paper provides a new approach for power flow and modeling analysis of three phase unbalanced radial distribution systems (URDS) using the simple forward/backward sweep-based algorithm. A three phase load flow solution is proposed considering voltage regulator and transformer with detailed load modeling, for the transformer modeling symmetrical components theory is used and zero sequence-vo...

The use of buck-derived topologies for unity power factor ac-to-dc applications is limited by their inherent inability to draw current from the line in those intervals, during the line half period, in which the input voltage is lower than the output one. This drawback is overcome in the proposed high-quality rectifier based on the forward topology with secondary-side resonant reset. The employe...

A pair of ion cyclotron range of frequencies (ICRF) antennas in the large helical device (LHD), HAS antennas showed high efficiency in minority ion heating. However the low loading resistance must be increased to prevent breakdown in transmission line. Moreover, the voltage and the current around the feed-through must be reduced to protect it. For these purpose, we developed a design procedure ...

Single phase voltage converter structure with isolation transformer for applications in traction vehicles is presented. This paper shows simulation model of this type of converter and transformer model with modern magnetic material in OrCAD-PSpice simulation program. Two PWM control techniques are compared in order to eliminate voltage and current oscillations in primary winding of the transfor...