Jamal Rizk

How to design an effective earthing system to ensure the safety of the people

Performing High Voltage (HV) maintenance with a multicraft work force creates a special set of safety circumstances. The safety of people including workers will be discussed in this paper. In Addition, this paper will present an effective approach to design an earthing system. This approach explains the theoretical background necessary to perform the calculation of the required safety voltages. Finally, this paper provides a verification of the proposed approach via simulation with Current Distribution, Electromagnetic Fields, Grounding and Soil Structure Analysis CDEGS software.

Design of permanent-magnet generators for wind turbines

There has been much interest and studies in high efficiency wind generators with permanent magnet excitation due to the increasing availability of permanent magnet materials, especially NdFeB. The present paper aims to outline the design and analysis of such a PM generator. The generator that is being used will be an 8-pole permanent magnet generator rated at 5 kW and using NdFeB for the field excitation. The details of the permanent magnet generator are also presented.

Design and performance of permanent magnet slotless machines

The paper presents various configurations of PM slotless machines. The design aspects to achieve optimum efficiency are also discussed. The paper also presents various configurations of slotless windings. The details of practical windings are also given. The extra eddy current loss and its reduction are also discussed. The comparative performance of two types of slotless windings is also presented.

Design and Development of Magnetic Torque Couplers and Magnetic Gears

New breed of permanent magnets are increasingly being used in novel permanent magnet electromechanical devices. This paper deals with the application of rare-earth magnets in the design of synchronous magnetic torque couplers and magnet gears. The performance of experimental devices is compared with finite element analysis.

Conversion of a switched reluctance motor to operate as a generator for wind power applications

Climate change effect become number one concern in many countries due to the effect that will have on human life. Renewable energy found to be one of the most effective ways to overcome this problem, wind energy is part of the renewable and one of the most growing areas in this field. In this paper the definition of switched reluctance generator and the principal of operation will be discussed, the excitation cycle and its relation to the switching parameters, methods on the switching phenomena will be discussed, low speed circuit and high speed circuit will be explained, output power of the SRM

Development of Planning Procedures with Embedded Solar Systems

Abstract In this paper, the impact of solar photovoltaic generators deep in a typical urban medium and low voltage distribution networks is examined. Using a concept of equivalent net loading, a novel yet simple method is proposed wherein an “effective” level of solar input, based on readily available sunshine data, can be estimated over the summer peak load period and incorporated into traditional planning procedures.

Fault current distribution and pole earth potential rise (EPR) under substation fault

Abstract New high-voltage (HV) substations are fed by transmission lines. The position of these lines necessitates earthing design to ensure safety compliance of the system. Conductive structures such as steel or concrete poles are widely used in HV transmission mains. The earth potential rise (EPR) generated by a fault at the substation could result in an unsafe condition. This article discusses EPR based on substation fault. The pole EPR assessment under substation fault is assessed with and without mutual impedance consideration. Split factor determination with and without the mutual impedance of the line is also discussed. Furthermore, a simplified formula to compute the pole grid current under substation fault is included. Also, it includes the introduction of the n factor which determines the number of poles that required earthing assessments under substation fault. A case study is shown.

Design and performance of interior permanent magnet motors with saturating magnetic bridge

Permanent magnet (PM) machines are capable of high efficiency, high power density and extremely wide power operating range. With these characteristics there has been considerable interest in applying them for motion control and robotic applications. Due to their high efficiency, PM machines are ideal general drives in many consumer goods to reduce energy consumption and improve performance. This paper outlines design, fabrication and simulation of interior permanent magnet machines (IPM) with and without saturating magnetic bridge. Based on the study, an IPM is fabricated, tested and performance compared with an equivalent induction motor. The design details of the fabricated IPM machine are also given.

Optimisation of flux barrier parameters in synchronous reluctance machines

This study is part of research to improve the efficiency of synchronous reluctance machines. This paper presents study of optimum flux barrier width of the synchronous reluctance motor (Syn-RM) and its performance. Total of 17 designs are simulated, and post-process results are presented to conclude optimum barrier width by applying FEM techniques. However, due to the non-linear magnetic relationship in the air gap and machine core material, the analytical method is used only to confirm the validity of FEM results. Secondly, an optimum location for flux barriers obtained for further analysis on barrier width. The core of the study divided into two analyses such as single flux barrier width analysis by placing the barriers at the optimum location and then the final result further analyzed to confirm the location of the barrier.

Power quality improvement factors: An overview

The power quality has started to play an important role in the electronic industry. As the power providers are turning to smart grid and smart meters, the standards for power quality needs to be revisited. The power quality can be categorized into two groups, one addressing the standard for the power quality supplied at the grid level and the other group which deals with the factors that affect the power quality at user level. These factors include harmonics, voltage changes, sags, transients, voltage unbalance, etc. These factors will provide us in-depth details on the power system. In this paper, an overview of various factors will be presented in order which can affect the power quality of the system. The paper will also look briefly at the measurement techniques used to measure them.