Electrical Insulation Magazine – Nov/Dec 2018 Issue
The November/December Issue of the Electrical Insulation Magazine has been released. Use the accordion headings below to explore this issue’s content, and visit the IEEE Xplore for full magazine access.
For a list of upcoming conferences, please visit the conference page or check out the events calendar.
Editors & Featured Articles
From the Editors’ Desk, Nov-Dec ’18
Stanislaw Gubanski, Editor-in-Chief
stanislaw.gubanski@chalmers.se
Resi Zarb, Co-Editor
resi.zarb@ieee.org
Updated Scope & Author’s Guide
In this issue, we are pleased to introduce a revised Scope for the Magazine, as well as an updated Author’s Guide. Highlights of the improved Scope include:
- Authors are required to submit an abstract for review prior to writing a full paper
- Creation of an editorial board whose responsibility it will be to evaluate all abstracts
- Implementation of a page limit for technical articles
- Adherence to a particular style for technical articles
Moving forward you will find the Magazine Scope clearly displayed on the inside front cover, while the Author’s Guide will remain on the inside back cover. Authors should review the requirements before submitting articles.
Young Professionals
In this issue, Valeria Pevtsov of Manitoba Hydro’s High Voltage Test Facility describes her experiences attending the Electrical Insulation Conference and Working Group Meetings. Valeria also represented MHI as an exhibitor and made one of the commercial presentations at the conference.
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Review of This Month’s Articles
The three articles in this issue are in general dedicated to cable diagnostics and technology. The first one is “Wireless Partial Discharge Tracking on Crosslinked Polyethylene MV and HV Cables” by a team of researchers from academic and industrial centers in Italy – University of Palermo (A. Madonia, E.R. Sanseverino and P. Romano), Prysmian (I. Troia, S. F. Bononi and M. Albertini) and University of Bologna (S. Giannini and G. Mazzanti). It describes the effectiveness of a partial discharge (PD) location method relying on a novel portable wireless detection system. After describing the principle of wireless detection and the main features of the wireless measurement system, two applicative examples are provided, relevant to XLPE-insulated AC cables: a MV cable and an EHV cable. For the MV cable, conventional PD measurements were first performed in the laboratory by means of a standard acquisition system. PD activity was detected, but the system allowed the operator to locate the PDs only on a length of 70 m. Aiming at a more accurate pin-pointing of the defect, more measurements were carried out using the novel detection system, whereby the source of PD activity was located and identified as a batch of internal defects on the inner semiconducting screen. For the EHV cable, wireless PD measurements were performed at different points along the cable after the installation on site. As a result PD activity was located on cable accessories. The presented results prove applicability of the wireless PD detection portable instrument by showing that it is able to locate various PD sources as well as provide indications for their correct classification.
The second article is “Partial Discharge Signal Propagation in Medium Voltage Branched Cable Feeder” by an international research team from Finland (University of Vaasa), Spain (University Carlos III in Madrid) and American University of Kuwait. The authors are M. Shafiq, K. Kauhaniemi, G. Robles, G. A. Hussain and L. Kumpulainen. This article elucidates the propagation behavior of partial discharge signals across the branched MV cable joints, which significantly helps to improve the performance of condition monitoring and diagnostic solutions for medium voltage cable networks. PD signals emerging due to insulation faults in the MV cable network travel along the lines and split into the connected branches at the splices. The analysis of the PD pulses at these critical points in the network is complex as compared to straight cable sections and joints. The paper describes experimental investigations which were made in a laboratory environment using MV cables where PD measurements were conducted using high frequency current transformers. When a PD pulse emerges at a certain location of a cable and it reaches the branched joint, the resultant change of impedance at this point causes reflections, which are measured and analyzed using transmission line approach. The characteristic impedance plays an important role here and determines the split of the PD energy at the joint. A detailed analysis of the measured PD signals provides not only a comprehensive interpretation of the splitting of PD current pulses at the joint but also identifies the faulty cable section among the branched cables. The effects of various factors, such as attenuation, dispersion, reflections of the signals, as well as the effect of measurement system configuration, are also presented.
The third contribution in this issue, entitled “Polymeric Insulation for HVDC Extruded Cables: Challenges and Development Directions” is a review article by Zhonglei Li and Boxue Du from Tianjin University, China. Assuming that high-voltage direct current (HVDC) extruded cables will continue to play a key role in the global power grid in the future, particularly for high-voltage, large-capacity, long-distance power transmission and regional power grid interconnection, the article reviews the challenges and development directions of polymeric insulation for this type of cable. The electrical properties of the ideal cable insulation materials, including low dc conductivity insensitive to the ambient temperature, high breakdown strength independent of temperature and polarity reversal, low space charge accumulation and stability under high temperature, are elucidated. The effects of the trap level distribution on the electrical properties are analyzed comprehensively. Additionally, quantum chemical analysis (QCA) using density functional theory (DFT) is described as an effective method to evaluate the electronic structure and the trap level distribution in polymeric insulation, which can guide the design and manufacture of the future HVDC insulation. The development directions of polymeric insulation materials, including high-purity XLPE compounds, XLPE nanodielectrics, modified material systems using organic additives (voltage stabilizer and polar additives) and PP-based insulation, are reviewed to outline their advantages and disadvantages. Accordingly, further research topics for each development direction are proposed to support the future development of HVDC extruded cables for voltage levels up to ±800 kV.
Featured Articles
Wireless Partial Discharge Tracking on Cross Linked Polyethylene MV and HV Cables
Madonia, Sanseverino, Romano, Troia, Bononi, Albertini, Giannini and Mazzanti – Xplore Link
Partial Discharge Signal Propagation in Medium Voltage Branched Cable Feeder
Shafiq, Kauhaniemi, Robles, Hussain and Kumpulainen – Xplore Link
Polymeric Insulation for High-voltage DC Extruded Cables: Challenges and Development Directions
Li and Du – Xplore Link
Editorial
EDITORIAL
by Dan Martin
Australasian Transformer Innovation Centre, the University of Queensland, Australia
What will be the demands of the power industry on the electrical insulation of their primary assets into the future? In Australia, there is a major shift to renewable generation, driven by both consumer demand and government policy. Electric vehicles are likely to become mainstream in the future, although their uptake has not been significant in Australia so far. Consequently, the focus is on renewables. The utilities are under government regulator pressure to cut network costs. Billions of dollars have been invested in the current-carrying components of the grid (e.g., power transformers, distribution transformers, switchgear, and cables), all of which contain electrical insulation. How will their operation, maintenance, and replacement change in a world with a high penetration of renewables? The Australasian Transformer Innovation Centre has partnered with a number of local organisations to address this concern.
In Australia deregulation has brought about a structure in which commercial generators bid into the market, which is managed by the Australian Energy Market Operator, a federal government body. The transmission and distribution utilities operate as monopolies whose expenditure and income is regulated by the Australian Energy Regulator. The federal government has a policy that 20% of Australian electrical power should be derived from renewable sources by 2020. Some state governments already have longer-term policies: Queensland aspires to 50% by 2030, Victoria to 40% by 2025, South Australia to 75% by 2025, and Tasmania (which has abundant hydroelectric power) to 100% by 2022. Over the past few years there have been several high-profile retirements of aging coal-fired generators, and the costs of large-scale solar have fallen sufficiently that the generation companies have chosen to build photovoltaic plants rather than coal-fired generators. Of course, renewables present challenges with intermittency and availability, and there have been lively discussions within the industry on practical solutions (e.g., using pumped-hydro, battery storage, gas generation to coexist with the renewables, and strengthened transmission lines between the Australian States).
At the distribution level there has been a very high uptake of small-scale rooftop photovoltaics (PVs), driven by generous power export tariffs and a wish to avoid increasing grid electricity costs. Currently, nearly one in three Queensland households have rooftop PVs. Two significant developments are likely over the next few years: (1) transactive energy options, where a house with PV can sell its surplus energy to its neighbors at a negotiated price, rather than to the grid at a fixed price, and (2) use of batteries so that a household can choose to store its surplus energy for later use rather than sell it to the grid.
What does all this mean for a utility in terms of the electrical insulation of its plant? A common theme is prevention of cost increases, due to unnecessary asset replacement costs being passed on to the community. Most of the large-scale solar installations will be located inland where there is a dry climate, solar insolation (exposure to the sun’s rays) is high, and there are few clouds. However, these areas have a relatively low population density, and the existing electricity network is not very extensive. When the solar plant is installed, power transformers and cables originally lightly loaded may become heavily loaded, which was not initially intended. The utilities are aware that the remaining life of insulation within a substation may then become shorter, but they prefer to operate existing equipment to its end of life rather than replace it earlier. Accordingly, the Australasian Transformer Innovation Centre is focusing on how a utility can determine accurately the remaining service lifetime of electrical insulation and the maintenance strategy that should be followed.
The insulation in transformers consists essentially of Kraft paper and mineral oil, and in cables it is usually cross-linked polyethylene, although some mineral oil–filled cables are still in use. The contemporary models on which remaining lifetime calculations are based are essentially thermal models. The load, ambient temperature, design, and environmental factors are used to calculate the maximum temperature of the insulation. The maximum temperature is then used in conjunction with chemical models to calculate the rate of degradation and the remaining lifetime. However, quite often there is little temperature monitoring in older equipment. If these assets are to be run at higher current, more monitoring may be required to enable a utility to determine sufficiently accurately the increase in degradation rate and to plan for replacement where necessary.
The inverters that connect the renewable generation sources to the grid mostly use pulse-width modulation to approximate an AC sine wave. There has been some suspicion that the voltage fast rise times will lower the inception voltage of partial discharge in insulation, thereby reducing its remaining lifetime. Voltage and current harmonics from the inverters may cause greater energy dissipation in the form of heat in cables and transformers, heating the insulation to temperatures higher than expected. It must be remembered that an increase of only 6°C will reduce the remaining life of Kraft paper insulation by 50%. This potential problem is under investigation.
Many medium voltage (e.g., 11 kV) and low voltage (230–240 V) distribution networks are unmonitored, because of the very large number of feeders and lines. When these systems were initially set up the voltage was controlled automatically by a tap-changer on a zone substation transformer, or by manual adjustment of the tap setting of a distribution transformer. This strategy was appropriate when power flowed from the transmission system to the zone substation and then to the customer (i.e., the voltage decreased from the zone substation to the consumer). However, when the voltage along the line is more variable, due to variable rooftop PV generation, the utilities may need to adjust the voltage more frequently. In that case an automatic tap changer may require more frequent maintenance.
In the project being undertaken by the Australasian Transformer Innovation Centre, three different cases are being studied. The first is a zone substation around 20 years old, located in a historically lightly loaded part of the network. Given large-scale solar generation, the assets within this substation will run at higher loading than originally planned, as discussed above. Under normal usage the utility would expect another 30 years of life from the substation assets. The aim of the study is to determine whether under large-scale solar generation the same life can be expected, whether more maintenance is required, and whether the assets must be replaced earlier than initially envisaged.
The second case is a remote outback town where the solar PV has an output around four times the local load. The analysis will focus on the maximum amount of power that can be exported through the existing assets, without overloading them. In particular, during hot days less energy needs to be exported because the air conditioning load of the town increases, and thus, the insulation temperature is less likely to increase to dangerous levels, because the load current is less.
In the third case large-scale solar generation is being connected directly to the local transmission grid using a new power transformer. The generator company will pay for the high-voltage infrastructure required to connect their PV, and the utility will maintain it. The generator and utility must collaborate to ensure that the proposed assets are maintained efficiently into the future. An important point is that
whereas a utility usually expects that its primary plant will last 40 to 50 years, a solar generator is expected to last only 20 to 30 years. Because the high-voltage infrastructure need not last so long, reduced initial cost is a possibility.
Likely future requirements of the utilities are as follows:
• More work is expected in order to better understand how grid-connected inverters affect the insulation of primary assets, and how the residual life of the assets changes.
• The utilities’ desire to operate insulation closer to its end of life will require more monitoring and better analysis, the latter resulting mainly from a better understanding of how dielectrics age when subjected to the pulse-width modulation output of an inverter.
• Because the electrical insulation of assets is not required to last longer than the expected life of the solar panels, the utilities may seek reduced insulation specifications, potentially driving innovation in asset designs.
• Distribution transformers and cables may require more monitoring, because the uncertain power flows between PV exporters and energy-importing households may overload these normally unmonitored assets.
The aim of the research being planned at the Australasian Transformer Innovation Centre is to assist utilities to manage the transition to a high penetration of renewable sources and any resulting effect on their insulation-containing assets.
News From Japan
by Y. Ohki
Inside the Institute of Electrical Engineers of Japan, abbreviated as IEEJ in this article, there is an organization called Investigating R&D Committee, whose task is to search the status quo and future trend of research and development on a specific technology or topic relating to electrical engineering. As of June 15, 2018, a total of 125 such committees are conducting activities to pursue the objective of each committee in various fields within the scope of IEEJ.
For three years, from July 2015 to June 2018, the Investigating R&D Committee on Advancing Tailor-made Composite Insulation Materials (TMC) was set up inside the Technical Committee on Dielectrics and Electrical Insulation (TC-DEI). The chair of the TMC Committee was Prof. Toshikatsu Tanaka (Figure 1) of Waseda University. Here, the composite means a solid material, in which (an) inorganic filler(s) are added as (a) guest(s) to a host insulating polymer such as polyethylene and epoxy resin. Since the year around 2000, nanocomposites, namely, composites composed of guest inorganic fillers with sizes less than around 100 nm and host polymers, have attracted much attention as attractive insulating substances that can improve various dielectric and electrical insulation properties. Although Tanaka is already officially retired from Waseda University, he is still very active. As a regular activity as the chair of the TMC Committee, he convened four meetings annually or a total of 12 meetings during the three-year period. In addition to this regular work, he introduced many new, active, and challenging activities to his committee. Digital publishing of TMC Newsletters is one of these activities. Figure 2 shows its first issue, which was named No. – (minus) 1 issue published electronically in April 2015. Since then, a total of 36 newsletters, inclusive of Nos. -1 and 0, were published monthly until No. 34 issued in June 2018. Every newsletter is composed of five articles; a message from the chair, twitter from a member, paper of the month, techno-scrap, and activity and meeting calendar.
Figure 1. Toshikatsu Tanaka of Waseda University.
Figure 2. First issue of the TMC Newsletter, named No. − (minus) 1, published electronically in April 2015 (with the permission of IEEJ).
Figure 3. Photo of Linda S. Schadler (Rensselaer Polytechnic Institute, USA, center, front row) and members of the TMC committee, taken November 10, 2016, on the occasion of the Special Workshop of Nanodielectrics.
The second activity that should be reported here is that the TMC Committee held several special seminars. On the 10th of November 2016, the first special seminar was held. Prof. Linda S. Schadler of Rensselaer Polytechnic Institute gave her talk with a title of “Polymer Nanodielectrics – The Development of a Design Approach” as a special invited speaker of this symposium. Figure 3 is a picture taken on that occasion.
Besides the above symposium, the TMC Committee held two more symposia. The first one was held as a special activity affiliated with the Eighth International Symposium on Electrical Insulating Materials (ISEIM), Toyohashi, 12-15 September 2017, on the previous day of the opening of the 8th ISEIM. Nine members of the committee, including the Chair, Prof. T. Tanaka, were the lecturers. At this symposium, the lectures used a book [1], entitled “Advanced Nanodielectrics – Fundamentals and Applications” as a textbook. Figure 4 is a photo, showing a scene of Dr. Yasuhiro Tanaka, President of IEEJ TC-DEI and Professor of Tokyo City University, sharing his knowledge during the symposium.
Figure 4. Yasuhiro Tanaka, president of IEEJ TC-DEI and professor of Tokyo City University, sharing his knowledge during the symposium.
Figure 5. IEEJ Technical Reports published by the first and the second committees [3], [4].
Figure 6. Front cover of the Japanese book published in August 2014 [5].
Figure 7. Front cover and contents of the English book “Advanced Nanodielectrics Fundamentals and Applications,” published in May 2017 [1].
Figure 8 shows the award certificate, which was delivered to the members of the fourth committee at the annual general assembly meeting of IEEJ on May 31, 2018. It reads, “The IEEJ certificates that the Investigating R&D Committee on Advancing Tailor-made Composite Insulation Materials has been awarded the IEEJ Outstanding Contribution Award for its issue of English translated book “Advanced Nanodielectrics: Fundamentals and Applications” of the original IEEJ Technical Report and Success of Related Workshop in ISEIM 2017”.
Figure 8. Certificate of IEEJ Outstanding Contribution Award (with the permission of IEEJ).
This article was completed with the help of Dr. Masahiro Kozako of Kyushu Institute of Technology and Dr. Takahiro Imai of Toshiba Energy Systems and Solutions Corporation.
References
[1] T. Tanaka and T. Imai (ed.), “Advanced Nanodielectrics -Fundamentals and Applications-” Pan Stanford, Singapore, 2017 (ISBN978-981-4745-02-04).
[2] Y. Ohki, “News from Japan –Activities of Investigation Committees, IEE Japan-”, IEEE Electr. Insul. Mag., Vol. 20, No. 1, p.54, 2004.
[3] T. Tanaka (Ed.), “Technology and Application of Polymer Nanocomposites as Dielectric and Electric Insulation”, Inst. Electr. Engn. Japan, Technical Report No. 1051, March 2006 (in Japanese).
[4] T. Tanaka (Ed.), “Characteristics Evaluation and Potential Appllications of Polymer Nanocomposites as Evolutional Electrical Insulating Materials”, Inst. Electr. Engn. Japan Technical Report No. 1148, March 2009 (in Japanese).
[5] Original Japanese version of [1], Inst. Electr. Engng. Japan, Aug. 2014 (ISBN 978-4-88686-294-5) (in Japanese).
Up And Coming Professional
Up And Coming Professional – Valeria Pevtsov
Book Review
High Power Microwave Tubes – Basics and Trends
Kesari and B.N. Basu
Morgan & Claypool Publishers
IOP Concise Physics
1210 Fifth Ave, Suite 250
San Rafael, CA 94901
Phone: 415-785-8003
Fax: 415-785-2507
http://www.iopscience.org/books
http://www.morganclaypool.com
ISBN 978-1-68174-560-2 (volume 1, $55, softcover, 2018)
ISBN 978-1-68174-705-7 (volume 2, $49, softcover, 2018)
The IOP Concise Physics series of books are short texts that provide readers with an introduction to key principles of current research topics. These books are focused at researchers and students of all levels with an interest in physics and related subjects.
This two-volume set introduces the fundamentals of high power microwave tubes. Volume 1 focuses on the operation and basic principles of microwave tubes while volume 2 provides details on various types of high power microwave tubes commonly used today.
Volume 1 contains five chapters. Chapter 1 begins with a historical perspective of electron tubes and microwave tubes (MWT) including limitations of frequency response and how many of these limitations are overcome. Chapters 2 and 3 outline the classification of MWTs and the various uses of each type of MWT for military, medical, scientific, and industrial applications. Chapter 4 focuses on the basic concept of electron guns – the Pierce gun made from a flat or curved cathode surface for O-type tubes, and a cusp-shaped gun surface for small-orbit and large-orbit gyro-tubes. Also discussed are the traditional magnetic focusing structures for electron beam confinement. Chapter 5 presents an analysis of helical slow-wave structures along with optimization methods to obtain the desired dispersion characteristics for increased wideband performance.
Volume 2 also contains five chapters which continue from volume 1. They cover specific MWT types. Chapter 6 covers conventional MWT (i.e. traveling-wave tubes, klystrons, and crossed-field tubes). Chapter 7 provides details on the operating principles of fast-wave tubes including the cyclotron resonance maser, gyrotron, gyro-klystron, slow-wave cyclotron amplifier, and peniotron. Chapter 8 contains the operating principles of vacuum microelectronic tubes and the principles of vacuum microelectronic technology. Devices that are discussed include plasma filled tubes, relativistic MWTs, high-power Cerenkov tubes, and Vircator tubes. The last two chapters contain information on frequency and power ranges of common microwave tubes, trends and future directions for MWTs.
With very few new books on microwave tubes being written, this set provides a fresh introduction to microwave tubes for interested students and professionals who want to learn more about traditional microwave technology. Its concise format provides for a quick understanding of the material being presented and the references provided allow for further more in-depth study as desired. These volumes will give the reader a good basic understanding of traditional microwave tube technology which still dominates in high-power applications, even with the many advances in solid-state technology.
A-Level Chemistry’s Best Kept Secrets! – What Top Students Know That You Don’t
Tan and L. Pereira
WS Education
An Imprint of
World Scientific Publishing Co.
5 Toh Tuck Link
Singapore 596224
US Office:
27 Warren Street
Suite 401-402
Hackensack, NJ 07601
Phone (201) 487-9655
Fax (201) 487-9656
http://www.worldscientificpress.com
ISBN 978-981-3220-12-6
223p. $35 (softcover), 2018
While A-Level standards for courses is used in the UK, this book is still an excellent reference for students studying chemistry basics. In the UK, A-level chemistry syllabus is based on an understanding of a broad coverage of topics in chemistry that includes physical, organic, and inorganic chemistry. This book can be used as a supplementary text for A-Level chemistry courses or in advanced high school or a first-year college chemistry class.
It consists of three sections – General and Physical Chemistry, Inorganic Chemistry, and Organic Chemistry. The first section covers fundamental topics ranging from atomic structure, chemical bonding, chemical energetics, equilibria equations, and reaction kinetics. The next section, inorganic chemistry, covers chemical periodicity, Group II and Group VII elements, and transition elements. The third section, organic chemistry, describes structure and bonding fundamentals, introduces isomerism, hydrocarbons, halogen derivatives, hydroxy compounds, carbonyl compounds, and nitrogen compounds.
This book will help the reader make connections between the different branches of chemistry. Along with the theory, there are examples of recent technology applications used to help reinforce the theory being presented. One example in electrochemistry shows how to determine the reaction equations for a modern fuel cell. Many other examples show sketches of practical experimental setups used to illustrate the theory being presented. Rather than only present equations and theory, the authors spent a large effort to insure the reader will gain a better understanding of the concepts being presented through the use of examples, applications, illustrations, and experiments. There are also general trends, rules-of-thumb, common mistakes, and practical explanations for each topic.
If you know someone studying chemistry or you just want to brush-up on basic chemistry, then this book is an excellent way to quickly understand many fundamental concepts in three broad areas of chemistry.
An Introduction to Chemical Kinetics
C. Vallance
Morgan & Claypool Publishers
IOP Concise Physics
1210 Fifth Ave, Suite 250
San Rafael, CA 94901
Phone: 415-785-8003
Fax: 415-785-2507
http://www.iopscience.org/books
http://www.morganclaypool.com
ISBN 978-1-68174-665-4
79p. 39.91euro (Softcover), 2017
The IOP Concise Physics series of books are short texts that provide readers with an introduction to key principles and current research topics. These books are focused at researchers and students of all levels with an interest in physics and related subjects.
This book is an introduction to the main principles of chemical kinetics. It originated from a set of lecture notes from a core first year lecture course in physical chemistry taught by the author at the University of Oxford. It provides a concise introduction to a key principle in chemical kinetics that includes elementary reactions, collision theory, rate laws and reaction mechanisms. It also includes experimental methods and data analysis techniques for obtaining chemical kinetics over broad timescales.
After introducing elementary chemical reactions, rate laws are covered. These relate the reaction rate to reactant concentrations, an important fundamental concept to understand. The book continues with methods for experimentally obtaining reaction rate quantities. These include the various methods used to experimentally determine reaction rate order, rate constants, and monitoring concentrations as a function of time. There is also an introduction to complex reactions with a method to derive rate laws for complex reactions. The final chapter introduces the theory behind chemical explosions and the reactions necessary for an explosion to occur (or not to occur). One reason for measuring a reaction rate constants is that they are used in the Arrhenius equation, which is very commonly used to model chemical reactions over a valid temperature range.
The concise and focused nature of this book on a single topic makes it very readable. You will quickly grasp the fundamental principles and obtain a good working knowledge of this subject matter in this short book. Chemical kinetics is a stepping stone for many other processes and technology areas, especially in chemistry, vacuum science, and plasma physics. This is an outstanding review of a key topic in chemistry.
Control of Power Electronic Converters and Systems, Volume1
F. Blaabjerg, Editor
Academic Press
An imprint of Elsevier
525 B Street, Suite 1800
San Diego, CA 92101-4495
Tel: +1 619 231 6616
Fax: +1 619 699 6422
http://www.elsevier.com
ISBN 978-0-12-805245-7
392p. $127.50 (Softcover), 2018
Power electronic converters are used in a variety of systems for controlling and conditioning electrical power. They are used to change voltage levels, control frequency and power to a motor, convert DC to AC in PV arrays, and even allow for the bi-directional control of power flow in a microgrid. The popularity of these devices has received great attention lately due to the increasing use of wideband gap semiconductors (WBS). WBS enable greater efficiency, higher operating temperatures, and higher voltages as compared to traditional silicon-based components.
This book delves deeply into the inner workings of a wide variety of power electronic converters. It starts out by introducing the fundamental topologies of converters – voltage source and current source, and explains the differences, typical application, benefits and disadvantages of AC/DC, DC/AC, DC/DC, and AC/AC converters. This sets the foundation for future chapters which dive into the control theory for each type of converter for various applications. Basic analog and digital control principles are introduced before specific types are discussed. This introductory material focuses on the use of control targets and pulse width modulation (PWM) methods in converter design. This sets the foundation for the reader to understand more in-depth control methods used for each type of converter.
The control and modeling methods reviewed cover DC/DC, single-phase and three-phase AC/DC including phase-locked loops, single and three-phase DC/AC, and AC/AC converters. Fundamental designs for each circuit are described in detail along with modulation techniques, and control strategies. The reader will gain an in-depth understanding of control designs and control strategies for each type of converter. The book continues with the design and control of voltage source converters with LCL-filters, used to reduce the high inductance that would otherwise be present if a traditional L-filter was used. This continues with the modeling and control of photovoltaic (PV) systems and wind turbine systems. There are some details given on bypass diodes for sub-strings in PV arrays and methods of maximum power-point tracking. The final part of the book describes adjustable speed drives including the principle operation of induction motors and permanent magnet synchronous motors and the control methods used in drives for these motor types. Further, sensorless control of motor drives is also described involving control at ultralow-speeds and high-speeds, high-frequency signal injection based control and back EMF control of permanent magnetic synchronous machines.
Those interested in power electronic converters and variable speed drives will find this book very useful for understanding the fundamental topologies, circuit design, and control methodologies of these systems.
Wireless Sensor Systems for Extreme Environments
H.F. Rashvand and A. Abedi, Editors
John Wiley & Sons, Inc.
111 River Street
Hoboken, NJ 07030
Phone: (877) 762-2974
Fax: (800) 597-3299
http://www.wiley.com
ISBN 978-1-119-12646-1
499p. $140 (Hardcover), 2017
The use of wireless sensing technology is rapidly growing and the use of wireless technology in extreme environments is enabling new applications. Today, data collection from locations previously inaccessible with networked sensors can now be created with a shared data environment that can be used to monitor complex systems for sensing abnormalities and act to allow for predictive maintenance or action thereby preventing disasters or unplanned downtime.
This book details the most current state-of-the-art methods used in wireless technology for extreme application environments. It consists of five parts. Part I covers an overview of general methods used for wireless sensing in extreme environments. It begins with a very nice abstract describing each chapter giving the reader a very good overview of the details so the reader can quickly determine if they want to read that chapter. After these summaries, the remainder of Part I describes fundamental methods used in wireless sensing technology. This provides the reader, who may be unfamiliar with the latest methods, a basic understanding of this technology and many of the difficult key issues. These methods cover feedback and control, optimization of power consumption to extend life, connectivity schemes (multi-hop methods), rare-event sensing and event powered sensors.
The remaining four parts each cover a specific harsh environment for wireless sensing applications starting with Part II – Space applications. This very extreme environment explores battery-less sensors, disruption-tolerance networks to enhance the performance of Earth observation missions, especially if some data experiences more delay than others. Other areas include a complete sensor-node system from design to implementation and test for space launch vehicles. The robustness of adaptive networks to changes in the environment, topology or traffic, with centralized and distributed methods are discussed. Architecture details of sensor nodes and systems are also covered including A-to-D converters, DSP cores, ARM processors and wireless radio communications and new applications for near space (20-100km altitudes).
Part III investigates underwater acoustic sensing. It begins by introducing the reader to underwater networked sensors, their limitations, and potential applications. A wide range of various communication methods and recent advances are presented. Some of the specific communication methods discussed are underwater anchor localization using surface reflected beams and coordinate mapping methods. Security issues are also reviewed.
Part IV discusses underground and confined environments in general and specifically for agricultural applications. It details a magnetic induction based sensor system for underground application as well as other specific technical considerations for agricultural applications.
Part V covers industrial applications. These include structural health monitoring (e.g. bridges and other structures), RFID technology, power harvesting, and stress sensing using optical fibers. Other areas of wireless sensing cover aircraft and offshore windfarm monitoring with fault detection being the main topic for wind applications.
This book is a valuable resource for researchers, graduate students, and engineers who design and build wireless communication networks and sensors for control systems, emergency response systems, and other monitoring systems for predictive maintenance in extreme environments.
Transformer Aging – Monitoring and Estimation Techniques
T.K. Saha and P. Purkait, Editors
IEEE Press
John Wiley & Sons, Inc.
111 River Street
Hoboken, NJ 07030
Phone: (877) 762-2974
Fax: (800) 597-3299
http://www.wiley.com
ISBN 978-1-119-23996-3
466p. $160 (Hardcover), 2017
An oil filled power transformer begins to degrade the moment it is constructed and put into service. The insulation system degrades and this degradation rate depends on the operating conditions of the transformer. Thermal, oxidation, and hydrolytic processes are the main causes of aging. Over the years, there have been numerous methods developed to assess the condition of the insulation system in a transformer. Typically, these were offline sampling of the oil, such as a dissolved gas analysis (DGA), or other tests that required post-processing. These spot-checks of transformer condition over a period of time do not provide a continuous monitoring of the transformer condition. More recently, there have been in-situ methods developed to constantly monitor insulation condition. These methods may provide better predictive assessment of the transformer insulation and 24/7 monitoring that can alert an operator if a transformer needs maintenance. One of the most undesired events is an unplanned failure of a large power transformer. Regular spot-check sampling or continuous monitoring or both are essential to ensure transformer integrity, reliability, and long life.
This book describes the important aspects of transformer insulation from an aging perspective. It contains ten chapters. Chapter 1 describes the properties and applications of insulating materials in oil-filled power transformers including an overview of aging of oil-paper insulation systems.
Chapter 2 comprehensively explains various diagnostic methods that cover the dissolved gas analysis (DGA), furan analysis, and degree of polymerization (DP). Other measurement indicators described are insulation resistance, polarization index, dielectric dissipation factor, capacitance, power factor, dispersion factor, and partial discharge (PD).
Chapter 3 details the theoretical explanations of polarization-depolarization current (PDC), recovery voltage measurements, and frequency domain dielectric spectroscopy (FDS) including interpretation of results. Effects of moisture on these parameters are also described.
Chapter 4 reviews commonly used interpretation techniques for DGA, with machine-based learning, neural network analysis methods, and the various algorithms associated with these methods.
Chapter 5 covers a detailed analysis of partial discharge (PD) measurement methods and interpretation tools for transformer condition monitoring. Wavelet analysis and other advanced analysis methods are used to interpret PD signals. Feature extraction and waveform recognition are also discussed in this chapter.
Chapter 6 focuses on frequency response analysis (FRA) for mechanical deformation/displacement of transformer windings.
Chapter 7 explains online moisture measurement sensors. These are used to predict the remaining life of insulation as a function of the water content of the insulating paper.
Chapter 8 presents the fundamentals of biodegradable oil and their effect on paper insulation aging. Chemical and physical measurements and PDC and FDS interpretation schemes for biodegradable oils are presented, and a comparison to currently used condition monitoring methods used for mineral oils.
Chapter 9 details a methodology for transformer condition monitoring using online sensors and describes the use of numerical modeling to assist in interpreting sensor outputs and how to deal with statistical variance, measurement uncertainty, and how to combine sensor outputs to arrive at an overall condition assessment for the transformer “health.”
Chapter 10 highlights limitations of the present transformer condition methods and indicates areas that need further research and development.
This book is an excellent resource for engineers, teachers, and researchers interested in learning about the degradation processes and condition monitoring methods for insulation systems in oil-filled power transformers. It provides a very good introduction and background to the issue of condition monitoring and reviews many of the major methods used to assess the condition of these transformers. This type of information was up until this point, scattered throughout many journal and conference papers. This book provides one convenient source for all this research. It also provides insight into the future needs for further development of condition monitoring methods and sensors.
Quantum Field Theory
Fritzsch
World Scientific Publishing Co.
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ISBN 978-981-3141-72-8
166p. $68 (Hardcover), 2017
In theoretical physics, quantum field theory (QFT) is the theoretical framework for constructing quantum mechanical models of subatomic particles in particle physics and quasiparticles in condensed matter physics. It is a set of equations and mathematical tools that combine classical fields, special relativity, and quantum mechanics.
This book describes the dynamics of electrons and quarks as described by the Standard model of particle physics. After detailing classical mechanics and relativistic mechanics, the general framework of QFT is described. Quantization of scalar fields, spinor fields, and vector fields are described. Perturbation theory and symmetry concepts are introduced. Basic particle interactions are described by gauge theories which discuss quantum electrodynamics (QED) and quantum chromodynamics (QCD). Both electromagnetic and weak interactions are used in the gauge theory descriptions. Grand Unification theory are discussed in light of new progress in gauge theories.
This book is for readers interested in quantum field theory who already have a good background in quantum mechanics. While most of the mathematics presented consists of matrix math, integrals, curls, and partial derivatives, many of the discussions require some working knowledge of the concepts being described to fully appreciate the book.
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