Power Engineering Applications Research Articles

Thermodynamic models of extreme intermediate states and their applications in power engineering

Thermodynamic models of extreme intermediate states intended primarily for solving scientific and technical problems of power engineering are described. Examples illustrating the potential possibilities of using these models in developments and investigations of power engineering technologies are given.

MIS sensors for hydrogen content measurements in 10−4–102 volume percent range

New types of MIS (metal-insulator-semiconductor) sensors enabling direct measurements of hydrogen content in a wider range (up to 10 vol %) are developed. Using these sensors with special sampling techniques allows to measure hydrogen content up to 100 vol %. New class of hydrogen analyzers for various applications in hydrogen power engineering could be designed on the basis of new MIS sensors.

Interaction mediated by size differences between Y 2BaCuO 5 and CeO 2 particles in melt-textured YBCO superconductors

The Refining of Y 2BaCuO 5 (Y211) is crucial in the fabrication of YBa 2Cu 3O x (Y123) bulk superconductors with a high critical current density ( J c ) for power engineering applications. In this work, the influence of an addition of Y211 and CeO 2 of different sizes on the Y211 refinement and superconducting properties of melt-textured Y123 superconductors is investigated. Nano-size Y211 and nano-size CeO 2 were prepared by attrition-milling (250 rpm and 2 h). Using mixed powders consisting of 85 wt.% Y123, 15 wt.% Y211, and 1 wt.% CeO 2, Y123 quasi-single crystals were fabricated via a top seed melt-textured growth process. The interaction between Y211 and CeO 2 of different particle sizes was examined in terms of the size, uniformity and density of the Y211 particles that existed in the melt-textured samples. The reaction between the nano-size Y211 and the nano-size CeO 2 was more violent due to the more frequent collisions compared to the other reactions (micro-size Y211/nano-size CeO 2 or micro-size Y211/micro-size CeO 2), resulting in the most effective for refinement of Y211 particles and the best J c value of 4.2 × 10 4 (A/cm 2) (at 77 K and a zero-field).

Studying the technological characteristics of membrane elements with open pressure channels

The design of a membrane element for demineralization and softening of water in power engineering applications is considered. Advantages of the proposed element over ion-exchange filters are shown.

Towards Improvements in Thermal Efficiency and Reduced Harmful Emissions of Combustion Processes by Using Recirculation of Heat and Mass: A Review

Combustion processes are main constituents of several energy technologies. A key issue in combustion researches is the improvement in reduction of harmful emissions. Besides, the achievement of high-energy-efficiency processes through advanced heat recovery systems is desirable. When recirculated systems are utilized those two aspects can be achieved simultaneously. Therefore, the current review describes recent patented developments in heat and massrecirculating systems over the last 10 years (2000-2009). In relation to heat-recirculating systems recuperative, regenerative and porous media combustion are covered. The most significant inventions are discussed and their improvements and possible applications are emphasized. Further, flue gas recirculating systems novel configurations and solutions are described. Their practical power engineering applications in the field of e.g. boilers, internal combustion engines, gas turbines and radiant tube burners are emphasized. For each group of patents the principles of improvements in thermal efficiency and in reducing harmful emissions are expounded.

Combustion science and problems of contemporary power engineering

Nowadays fine control of physical and chemical processes at combustion and detonation of hydrocarbon fuels, aimed at obtaining certain target characteristics for power engineering applications is getting more realistic. Since control implies deep understanding of interrelations between various phenomena, the role of basic science is crucial for attacking the problem. Discussed in the paper are the latest scientific accomplishments in the field of combustion and detonation control, in particular, the possibility of controlled flameless combustion of gases, controlled combustion in porous matrices, and controlled detonations, as well as the problems of practical implementation of controlled combustion and explosion.

Micromachined Electric-Field Sensor to Measure AC and DC Fields in Power Systems

This paper describes a new type of electric-field sensor that has been fabricated using micromachining technology. This micromachined sensor is dramatically smaller than conventional field mills, possessing a field chopping shutter measuring only 1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The shutter is moved using thermal actuators, thereby eliminating the wear and tear associated with rotating and moving elements of field mills. The sensor requires minimal operating power, with the shutter being driven by a 75-mV drive signal while consuming only 70 muW. The field chopping shutter operates at ~ 4200 Hz, enabling the measurement of both ac and dc fields. Two sets of sense electrodes enable differential field measurements and, therefore, do not require a reference ground potential. The sensor has a linear response to the electric-field amplitude and has demonstrated that it is capable of measuring a dc field as small as 42 V/m. This miniature sensor is the smallest sensor with such a resolution for use in power engineering applications.

Innovative and Emerging Concepts in Power System Instrumentation

Sensory information is used in power systems for protection, control, operator monitoring and decisions, and record keeping. Because of the importance of instrumentation, the development and use of innovative sensors is of concomitant importance. This article summarizes a few concepts in the area of innovative power system instrumentation. The instrumentation techniques are categorized by energy types: electric, magnetic, atomic, chemical, kinetic, luminous, and thermal. Since sensors detect energy in one form or another, categorization of sensors by energy type is a convenient way to describe sensors. Innovative instrumentation categories are identified for power engineering applications. Because this article is an assessment of innovative sensory technologies, some projected advantages and disadvantages are cited.

Multi-Agent Systems for Power Engineering Applications—Part II: Technologies, Standards, and Tools for Building Multi-agent Systems

This is the second part of a two-part paper that has arisen from the work of the IEEE Power Engineering Society's Multi-Agent Systems (MAS) Working Group. Part I of this paper examined the potential value of MAS technology to the power industry, described fundamental concepts and approaches within the field of multi-agent systems that are appropriate to power engineering applications, and presented a comprehensive review of the power engineering applications for which MAS are being investigated. It also defined the technical issues which must be addressed in order to accelerate and facilitate the uptake of the technology within the power and energy sector. Part II of this paper explores the decisions inherent in engineering multi-agent systems for applications in the power and energy sector and offers guidance and recommendations on how MAS can be designed and implemented. Given the significant and growing interest in this field, it is imperative that the power engineering community considers the standards, tools, supporting technologies, and design methodologies available to those wishing to implement a MAS solution for a power engineering problem. This paper describes the various options available and makes recommendations on best practice. It also describes the problem of interoperability between different multi-agent systems and proposes how this may be tackled.

Multi-Agent Systems for Power Engineering Applications—Part I: Concepts, Approaches, and Technical Challenges

This is the first part of a two-part paper that has arisen from the work of the IEEE Power Engineering Society's Multi-Agent Systems (MAS) Working Group. Part I of this paper examines the potential value of MAS technology to the power industry. In terms of contribution, it describes fundamental concepts and approaches within the field of multi-agent systems that are appropriate to power engineering applications. As well as presenting a comprehensive review of the meaningful power engineering applications for which MAS are being investigated, it also defines the technical issues which must be addressed in order to accelerate and facilitate the uptake of the technology within the power and energy sector. Part II of this paper explores the decisions inherent in engineering multi-agent systems for applications in the power and energy sector and offers guidance and recommendations on how MAS can be designed and implemented.

Interaction of magnetic field and magnetic history in high-temperature superconductors

Yttrium barium copper oxide (YBCO) coated conductors are now the most promising high-temperature superconducting tapes in terms of current capacity and price. One form of these conductors utilizes YBCO films on Ni–W metallic tapes and is being considered for a number of power engineering applications. In these applications, the conductor will carry an ac current, leading to energy losses, which are the focus of significant technical and experimental efforts. Our measurements of the ac losses of YBCO/Ni–W conductors carrying ac currents in applied dc magnetic fields have revealed a complex interaction between the magnetic materials present, the geometry of the conductor, the ac and dc magnetic fields, and the electromagnetic “history” of the sample. The investigation of this interaction is the main subject of this paper.

Introduction to "To the Question of Energy Use of DetonationCombustion" By Ya. B. Zel'dovich

Ya. B. Zel’dovich (1914–1987) made numerous contributions [1] to the theory of detonation, beginning with his very well known and widely translated article [2] on detonation structure that first introduced the standard Zel’dovich-von Neumann-Doring (ZND) model of shock-induced combustion. Even at that early stage of detonation research, Zel’dovich was also considering the application of detonations to propulsion and power engineering. He published these ideas in another paper [3] that has been virtually unknown in the West and has apparently remained untranslated until now. We are indebted to Sergey Frolov of the N.N. Semenov Institute of Chemical Physics for first bringing this article to our attention. We believe that the focus of this paper, which is the application of detonation waves to power generation and propulsion, is very relevant to the current activity on pulse detonation engines. In particular, Zel’dovich was apparently the first researcher to consider the questions of the relative efficiency of various combustion modes, the role of entropy production in jet propulsion, and the distinction between unsteady and steady modes of detonation in power engineering and propulsion applications. Even 60 years later, we believe that his results are relevant and can be of value in modern discussions on thermodynamic cycle analysis of detonation waves for propulsion [4]. For these reasons, we have arranged for the paper to be translated and suggested that it be published by the Journal of Propulsion and Power.

L p State Estimators for Power Systems

The widely used method of least squares for state estimation is revisited. The commonly used least squares philosophy is based on the L 2 Hölder norm. The L 1 and L ∞ norms are considered for applications in power engineering. The effects of outliers in measurements and multicolinearity on state estimation are studied. An application in parameter estimation for synchronous generators is given as an example.

Characterization of low AC loss elementary and assembled BSCCO conductors

A European consortium has progressed towards elementary and assembled conductorsviable for AC applications in the project ACropolis. The main goal was to achieve lowAC losses and high critical current densities in tapes developed for AC coils,transformers and cables. In order to verify the performance of tapes an extensivecharacterization programme was carried out. The dependence of critical current and AClosses on the parameters of the tape manufacturing process were scrutinized.Furthermore, SEM-EDX and DTA/TG analyses were performed to study thematerial microstructure, and the diffusion coefficient of oxygen through differentmatrix metals was measured. The homogeneity of the tapes was verified withmagnetic knife and Hall sensor experiments. Transport current measurements wereperformed at different mechanical stress conditions and also the distribution ofcritical current along long tapes was determined with a quasi-continuous four-pointmeasurement. The results confirmed that the low AC loss conductors can be produced onan industrial scale and they are competitive in power engineering applications.

Web-based tutoring in power engineering

This paper deals with the application of web-based technologies to power engineering education in an interactive student/mentor environment. The modern teaching/learning concepts and new technologies to support these concepts have been developed. This project incorporates web-based tools, including Internet, videoconferencing, and educational intelligent system modules for power engineering education. Different student learning styles are adapted for power engineering applications. The proposed interactive learning environment allows the mentor and students to best utilize the facilities for effective teaching and learning.

Magnetic losses in Bi2223 high temperature superconductors measured by AC and DC magnetization method

The properties of Bi2223 high temperature superconductor (HTS) tapes are improved in long length and high current-carrying capacity for its applications. But AC loss is still very high, which increases its economic feasibility in power engineering applications. Extensive investigations have shown that the mechanism of generation of AC loss in HTS is different from that in LTS because of its unique characteristics. In this study, AC losses in Bi2223 (HTS) tapes were measured by vibrating sample magnetometer at 77 K and AC susceptibility meter. The effects of different factors, such as, frequency and amplitude of AC applied magnetic field and/or amplitude of DC applied magnetic field, were investigated on the AC susceptibility in Bi2223 HTS tapes. Instead of Bean critical state model, flux dynamics were investigated to describe the experimental results.

Toward a model integration methodology for advanced applications in power engineering

This paper discusses a novel approach to model integration applied within electrical power engineering. A model integration methodology, exploiting the novel approach developed and underpinned by agent technology, is proposed.

Correction to "A current-based solution for transformer differential protection-part II: relay description and evaluation"

In the above paper, a truncated and, therefore, incorrect biography of Stanley Zocholl was published. We publish the correct biography for Mr. Zocholl here. Stanley Zocholl (LF’95) received the B.S. and M.S. degrees in electrical engineering from Drexel University, Philadelphia, PA, in 1958 and 1973, respectively. He joined Schweitzer Enginering Laboratories in 1991 in the position of Distinguished Engineer. He was with ABB Power T&D Company Allentown (formerly ITE, Gould, BBC) since 1947, where he held various engineering positions, including Director of Protection Technology. He holds over a dozen patents associated with power system protection using solid state and microprocessor technology and is the author of numerous IEEE and protective relay conference papers. Mr. Zocholl is an IEEE Life Fellow and a member of the IEEE Power Engineering and Industry Applications Societies. He is also a member of the Power System Relaying Committee and past chair of the Relay Input Sources Subcommittee. His biography appears in Who’s Who in America. He received the Best Paper Award of the 1988 Petroleum and Chemical Industry Conference and the Power System Relay Committee’s Distinguished Service Award in 1991.

Numerical simulation of disperse multiphase flows with an application in power engineering

AbstractThis paper deals with the numerical simulation of two‐phase flows based on the solution of the Navier–Stokes equations with a k–εturbulence model for the gas phase and a particle tracking model of the disperse phase fulfilling the framework of the Eulerian–Lagrangian (PSI‐Cell) approach. The numerical procedures for the two phases are based on the domain decomposition method applied to a block‐structured grid. The complete code is parallelized for computers of MIMD architecture. The paper gives a description of the numerical methods with special attention to the parallelization. Some test calculations demonstrate the performance of the code. The numerical simulation of a flow splitter from the field of power engineering is presented as an example for a real world application of the method. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Real-time digital processing of GPS measurements for transmission engineering

The Global Positioning System (GPS) is a state-of-the-art timing and positioning system based on 24 or more satellites launched and maintained by the US government. Power engineering applications based on GPS include phasor measurement, positioning applications, such as surveying and mapping, and potentially in deriving real-time data on transmission lines that will allow them to be loaded to a dynamic (thermal or security) limit. Inherent errors in GPS technologies are discussed, and the differential GPS method is described for accuracy enhancement. Further digital-processing needs are necessary for meeting the accuracy requirements of certain specific applications. The focus of this paper is on the digital signal processing (DSP) of differential-GPS (DGPS) measurements. The paper describes a methodology for further improving DGPS altitude measurements for the purpose of accurate determination of high-voltage overhead conductor sag. The Haar wavelet transforms (HWT) and least-squares parameter estimation (LSPE) techniques are considered.