Transformers are widely used in electric power system to perform the primary functions, such as voltage transformation and isolation. So the transformer design is emphasize. In this paper, a transformer design optimization method is proposed aiming at designing the transformer to optimize the efficiency and cost. The design optimization of transformer is formulated as unconstrained non linear m...

In this article, a multilayer piezoelectric transformer based on lead-free Mn-doped 0.94(Bi(12)Na(12))TiO(3)-0.06BaTiO(3) ceramics is presented. This piezoelectric transformer, with a multilayered construction in the thickness direction, is 8.3 mm long, 8.3 mm wide, and 2.3 mm thick. It operates in the second thickness extensional vibration mode. For a temperature rise of 20 degrees C, the tran...

A high-performance contactless electrical energy transmission (CEET) technique which employs the inductive energy transmission principle is described. The proposed technique enables the implementation of high-efficiency high-power-density fully regulated CEET systems suitable for applications with a wide input and load range. A high efficiency of the system is achieved by recovering the energy ...

Ferroresonance is a non-linear phenomenon and very dynamic in the power quality problems. This phenomenon should be carefully analyzed so that preventive measures could be taken before its appearance and prevent injury and damage to electrical power appliances. Ferroresonance is seen more in the middle-voltage networks with supplying unloaded or slightly loaded transformers by cables. The mater...

In this study, a disk-shaped piezoelectric transformer was fabricated using lead-free (K,Na)NbO(3)-based ceramics with high mechanical quality factor. The transformer can operate in the fundamental or the third radial vibration mode. The transformer is poled along the thickness direction. The top surface is covered by ring/dot silver electrodes separated by an annular gap which serve as the inp...

This paper presents the three topologies of three-phase four-wire DSTATCOM for reduction of harmonics, reactive power compensation, increasing power factor, which occur due to a nonlinear load, environment problem and polluted grid. The performances of the above topologies have been compared for the magnitude of source current, power factor improvement, DC-link voltage regulation, and total har...

AN OPTIC FIBER SENSOR FOR PARTIAL DISCHARGE ACOUSTIC DETECTION by Xiaodong Wang Partial discharge (PD) is a very common problem in operating power transformers and is one of the factors that could lead to failure of power transformers, leading to power outage and expensive repairs. The acoustic wave induced by PD can be measured and used for monitoring, diagnosing, and locating potential failur...

The recent development of high power DC/DC converters (more commonly know as Chopper Rectifiers) allows customers the option to keep older rectifier transformers and refurbished systems if reconfiguring or installing new cell line loads. Normally, new cell line impedances would require the replacement of transformer/rectifier equipment. This paper is intended to describe how one can change the ...

Ferroresonance is a highly dynamic and nonlinear power quality phenomenon caused by nonlinear inductances in ferromagnetic materials and power system capacitances. It is notorious for causing severe damage to power systems. This paper carries out an investigation into single-phase transformer ferroresonance initiated by switching transients. A hysteretic core model is implemented which includes...