INTRODUCTION THE electricity grid is an essential part of our social infrastructure, and with moves to protect the global environment gaining momentum internationally there is a strong need for environmental measures based on efficiency gains and other initiatives that make effective use of the materials and equipment that comprise the grid. The efficiency characteristics of amorphous transform...

Solid-state transformer (SST); Medium frequency transformer; AC/AC converter; Matrix converter Abstract This paper presents a novel topology of solid-state transformer (SST). In the design process, the AC/DC, DC/AC and AC/AC converters have been integrated to achieve higher efficiency. To obtain higher efficiency from other SST with DC-link topologies, the AC/DC and DC/AC converters have been i...

Based on natural ventilation design scheme for main transformer room of an indoor substation, different air distribution schemes were obtained by changing height and size of air inlets and outlets. Three-dimensional simulation of air distribution was conducted for the transformer room by using Computational Fluid Dynamics (CFD) method. Ventilation & cooling effect of different indoor ventilatio...

In the power system voltage sag become the important issue for industries. According to the survey 92% of the interruptions at industrial installations are voltage sag related. In various companies voltage sag may affect many manufactures and introduce sufficient losses in the power system. The voltage sag compensator, based on a transformer coupled series connected voltage source inverter, is ...

This paper presents the development of a wavelet based algorithm, for distinguishing between magnetizing inrush currents and power system fault currents, which is quite adequate, reliable, fast and computationally efficient tool. The proposed technique consists of a preprocessing unit based on discrete wavelet transform (DWT) in combination with an artificial neural network (ANN) for detecting ...

In this paper, we design a data transformer to transform Comma Separated Value (CSV) format into Health Level Seven (HL7) messages without losing syntax and semantics. The algorithm of the data transformer is similar to a generic parser for solving scheme-level mapping problems. It can be extended to transform non-uniform formats for exchanges among different hospital information systems. To sh...

A solid-state broadband beam deflector is described. This non-mechanical system steers spatially coherent broad band light to a common location in the far field. The components include a liquid crystal grating and achromatic Fourier transformer. The liquid crystal grating employs a polarization modulation scheme which produces a wavelength independent phase shift. The achromatic Fourier transfo...

Power systems should have acceptable reliability in order to operate properly. Highly available and dependable protective relays help to obtain the desirable reliability. The relays should be periodically evaluated during specific intervals to achieve the mentioned characteristics. The Routine Test Interval (RTI) should be optimized in order to economically maximize the reliability of the prote...