Mohamed A. El-Kady

Finite-Width Magnetic Mirror Models of Mono and Dual Coils for Wireless Electric Vehicles

Improved magnetic mirror models (IM3) for mono and dual coils with a finite width and infinite permeability are proposed in this paper. By introducing a mirror current, which is located at the same distance from a source current but with a smaller magnitude than the source current, the magnetic flux density of the mono and dual coils can be determined in a closed form. The ratio of the mirror current and source current is identified as a function of the width of the core plate and the distance between the source current and core plate, as rigorously derived from finite-element method simulations. Applying the proposed IM3 to the mono and dual coils used for wireless electric vehicles, the magnetic flux density over an open core plate is analyzed and its maximum points on the plate are found, which is crucial in the design of the coils to avoid local magnetic saturation. Furthermore, the magnetic flux density when a pick-up core plate is positioned over a primary core plate is also analyzed by introducing successive mirror currents. The proposed magnetic mirror models were extensively verified by experiments as well as site tests, showing quite promising practical usefulness.

Framework for Identification of Power System Operating Security Regions

Power system operation aims, in principle, at maintaining reliable and secure supply of electricity while minimizing the total cost of operation. In theory, there are two main objec-tives that could be considered, namely the maximization of system security and the minimization of total operating cost of supplying energy. In practice, however, the security requirements are included as constraints rather than formulating the problem as a security maximization mandate. The system security constraints are in fact boundaries that surround all possible operating modes (scenarios) of the power system. In other words, these boundaries form the feasible operating domain in the parameter space spanned by vari-ous operating variables within which the system can safely be operated. For a given operating scenario, the associated security level is measured by the “distance” (for example, the Euclidean norm) of the operating point from the security region boundary. This paper presents a novel framework for identification and representation of operating security regions in power systems as well as evaluation of security levels associated with different operating scenarios. While the concepts and principles presented are general, the work of this the paper is confined to the interpretation of the security boundary in terms of system stability criteria. Of course, the framework presented is applicable quite as well to other criteria that may be considered.

Application of operating security regions in power systems

During power system operations, the system operators are often struggling with identifying the dynamic operating security modes of the system in a fast, accurate and reliable manner. The system security constraints are in fact boundaries that surround all possible operating modes (scenarios) of the power system. In other words, these boundaries form the feasible operating domain - in the parameter space spanned by various operating variables - within which the system can safely be operated. For a given operating scenario, the associated security level is measured by the “distance” (for example, the Euclidean norm) of the operating point from the security region boundary. This paper reports on the results of a recently completed research and development paper, which included the development of innovative computerized schemes, which are capable of identifying dynamic operating security modes during the on-line operation of electric power systems. The methodology adopted in this paper includes the development of advanced, highly efficient computerized algorithms for fast identification of dynamic operating security modes of power systems. One of the salient outcomes of this paper is the development of a novel framework for identification and representation of operating security regions in power systems as well as evaluation of security levels associated with different operating scenarios. While the concepts and principles presented are general, the work of this paper is confined to the interpretation of the security boundary in terms of system stability criteria. Of course, the framework presented is applicable quite as well to other criteria that may be considered.

Supply quality improvement in electric power systems in Riyadh city, Saudi Arabia

Supply quality issues have been addressed, viewed, and reported by the electricity authority in the Kingdom of Saudi Arabia (KSA) and its customers with the common goal of improving the performance of the electricity system and ensuring that the electricity supply service is delivered according to the applicable national regulation and standard and with sufficient reliability and security. This paper presents the results of a recently completed study, in order to address and investigate the supply quality issues in industrial, commercial and residential sectors establishments. The work of the study included tasks to monitor measure and analyze the different supply quality parameters for various sectors, such as, industrial, commercial and residential sectors.

Assessment of Reliability and Quality Levels in Power Systems

This paper shares the results of a recent major industry-supported research and development study in which a novel framework was developed and applied for assessment of reliability and quality levels in real-life practical power systems. The approach is based on three metaphors (dimensions) representing the relationship between available generation capacities and required demand levels. The paper describes the new approach and presents illustrative practical applications to the Saud electricity system.