The May/June 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.

Featured Articles

Comparative Investigation on Fracture of Suspension High Voltage Composite Insulators: A Review—Part I: Fracture Morphology Characteristics

Yanfeng Gao; Xidong Liang; Yi Lu; Jiafu Wang; Weining Bao; Shaohua Li; Chao Wu; Zhou Zuo — Xplore Link

Do the Methods Used to Determine the Thermal Class of Rotating Machine Insulation Systems Make Sense?

Paul C. Gaberson — Xplore Link

Switchgear Condition Assessment and Lifecycle Management: Standards, Failure Statistics, Condition Assessment, Partial Discharge Analysis, Maintenance Approaches, and Future Trends

Aravinth Subramaniam; Animesh Sahoo; Sai Srinivas Manohar; Santosh Janaki Raman; Sanjib Kumar Panda — Xplore Link

Thomas Andritsch, Simon Sutton, and Frank Hegeler

Conferences During the Pandemic and Beyond

When first news reports of a novel Coronavirus, called SARS-CoV-2, spread around the globe not much more than a year ago, not many of us took notice. In the following months it was emails and calls from students, colleagues, and friends in the affected regions that made us aware of the scale of what was emerging. Much has changed since then, our personal lives have been turned upside down, travel has all but stopped, research has been impacted as access to laboratories has been restricted, and conferences needed to be cancelled or adapt quickly.

Doble’s client conference in early March was a sign of what was to come. An outbreak of COVID-19 in Boston (MA) the week before the event led to almost one third of the delegates withdrawing at the last minute. In June, the co-located 2020 EIC and IPMHVC were the first DEIS conferences directly affected by the pandemic. The general chairs and all supporting volunteers worked very hard to switch quickly to a virtual format. IPMHVC decided to not hold the 2020 event, preferring to delay the conference until 2022; this meeting is still scheduled to be held with the 2022 EIC in Knoxville, Tennessee. Because the 2020 EIC had already received and reviewed the majority of the conference papers, the EIC committee decided to go ahead with an online format. EIC used a platform provided by its conference publisher to upload prerecorded videos by the authors and held the first fully sponsored virtual DEIS conference over two weeks. The 2020 ICD, held just three days later, had not much more time to prepare. While ICD chose a different platform, they also relied on prerecorded videos, with questions posed to authors in text form.

The 2020 ICHVE and CEIDP had a little more time to prepare. Both were held via Zoom, with live plenary and poster sessions, as well as live question-and-answer sessions. These conferences adopted slightly different approaches to their conference schedule. The ICHVE scheduled all sessions like the physical event, but ensured authors would be assigned to sessions that were at a reasonable time of day in their respective time zone. The CEIDP took their usual three-day schedule and turned it “sideways” over a week and a half, scheduling live sessions from 12:00 to 15:30 universal coordinated time (UTC) each day; this way, participants on the US west coast had an early start, whereas participants from Japan had quite late evening sessions. The ICHVE as well as CEIDP recorded their plenaries, which allowed registered participants to catch up with any sessions they might have missed. DEIS members who missed these conferences, but are interested how such a live session worked, can still watch all 2020 CEIDP plenary sessions on the DEIS resource center: https://resourcecenter. deis.ieee.org/.

So, a year into the pandemic, what have we learned? In many ways the planning of virtual conferences should be simpler; there is no venue to book or conference dinner to stress over. However, we have found that we now need to check recordings, ensure we have presentations in advance (no more just-in-time delivery!), have rehearsals to check the Internet connection of live presenters, and make sure session chairs and speakers know what is expected of them. Just like the IEEE, Doble started with a familiar platform that had been used for some time to host webinars. It worked well in terms to presenting and controlling the Q&A, but the platform did not have an event-like feel for the delegates. Since then, a couple of dedicated virtual conference platforms have been tried, which offer a far better experience for the delegates. All three authors of this editorial have been chairing as well as attending a number of virtual conferences in 2020; we have learned that there is no “ideal” platform yet; every platform has advantages and disadvantages.

What is the purpose of a conference? There are as many answers as there are attendees, but the majority of answers narrow down to a few key points:

  • Dissemination of information—academic results and real-world experience
  • Getting valuable feedback from experts in the field
  • Networking with specialists in the field
  • Meeting new people working in related areas
  • Advertising your own work or products
  • Looking for job opportunities
  • Learning what competitors have been working on

Although videos and highly controlled Q&A sessions can satisfy a few of these points, it is becoming quite clear what attendees mean when they say that such an online conference does not have an event-like feel. Participants in their early career (researchers, students, and engineers) are particularly affected; they are missing out on valuable feedback from experts outside their own laboratories, institutions, or companies.

Preparing a video from the comfort of one’s home office (if you have the luxury of having one) can be a very soulless experience. Not being able to see the faces of participants or key clients can leave one feeling flat. From the perspective of an attendee, listening to a video or remote live speaker with the same attention as one would at a conference venue is also not easy. Family, children, cohabitants, pets, or delivery services ringing the doorbell: the remote office has many distractions not found at a conventional conference.

Some conferences also have a technical exhibition. Not only are these a means for companies to demonstrate their latest innovations, it is a means for the event organizers to generate revenue. Conference exhibitors, paying a fee for their booth, help offset some of the costs of running the event, thereby lowering registration fees. Some virtual conferences have held virtual exhibitions where delegates can tour a number of virtual booths, watch video content, and collect literature. However, almost no delegates used the option to start a one-on-one chat or video call with the exhibitors; delegates seem less willing to interact compared with how willing they are at a regular conference. This is bad news for the companies paying to exhibit in the virtual environment.

With a variety of video-conferencing platforms becoming day-to-day reality for many of us working remotely, organizers, volunteers, and participants have become adept in using these platforms. Those of us who are involved in online teaching and training have gotten used to talking to a camera rather than a human being. The inability to read body language or use hand gestures while explaining something has required presenters to modify their style; examples include using virtual laser pointers and highlighting features on graphs, diagrams, or photos with circles or arrows. But accepting the situation we are in and enjoying the prospects are two very different things. There are a number of conference experiences that the virtual environment cannot really reproduce, such as walking out of the auditorium at the end of a session, chatting with those in the audience, and getting immediate feedback. More generally, the virtual environment lacks all the impromptu discussions throughout the day and into the night, often initiated near a coffee dispenser or with alternative refreshing beverage in hand, and the in- depth discourse over lunch or dinner in small groups. In the real world, it is easier to approach new people and forge long-lasting international friendships.

There are, however, noticeable advantages of the virtual environment. It is possible to include speakers from more countries, bringing their unique perspectives and diversifying the discussion. The often high expenses for (international) travel, visas, hotel rooms, and conference registration fees place a high barrier to entry for many companies and universities. From experience, industrial events that might typically attract one or two delegates per company, now attract up to 40 from the same company to the same online conference. The online environment also allows participants to attend selectively specific presentations, dipping in and out for particular talks or sessions, without the need for a three-day time commitment.

The 2021 DEIS calendar shows virtual conferences for the 2021 EIC, ICPADM, and ISE as well. At the time of writing, the ICEMPE plans to hold a hybrid conference in Chongqing, China, in April 2021. The CEIDP currently plans to hold a physical conference in Vancouver, Canada, in October 2021.

A hybrid conference includes a physical conference venue combined with a virtual platform for people who cannot travel to the conference location. That would mean that all sessions would be live streamed to online participants, while still maintaining a physical meeting for those who can attend, i.e., those who can afford it. Even before the pandemic, the idea of hybrid conferences was discussed within IEEE and by other conferences organizers. However, for the conference sizes the DEIS is usually organizing, with 200 to 400 attendees, the hybrid format will be difficult to implement for technical and financial reasons. The first issue is that of availability and reliability of high-speed Internet access. Unless events are held at venues with a robust IT infrastructure, the interaction between live delegates and online delegates may be limited. In the longer term, venues may invest to mitigate this concern. Another key issue is that of finance: with most North American conferences being held in hotels, the resulting contractual liabilities and additional IT expenses will convince conference chairs to exclude hybrid options at this point. For conferences such as EIC and IPMHVC, which have exhibitors, a reduced number of in-person delegates would reduce the incentive to exhibit. This would mean the whole conference would not be financially viable, unless there would be drastically increased conference fees, which in turn would further reduce interest from delegates to attend.

How do we move forward in the post-pandemic era? Most of the attendees in 2020, who gave feedback, are looking forward to conferences being held in person again. On the other hand, the low cost of a virtual conference may meet a demand from some of our researchers. Should DEIS create a new annual/bi-annual 100% virtual conference with low registration fees? To pull off hybrid formats, our existing conferences will be difficult and expensive. Virtual registration fee for a hybrid format would be at least 70% of the on-site fee to offset the increased IT costs. And, how will virtual delegates cope with a conference schedule fixed to the time zone of the physical event? We would like to know your opinion and encourage all our readers to provide comments and participate in a survey, regarding the future of DEIS conferences. The survey can be found here.

Peter Morshuis

Interim Editor-in-Chief
peter.morshuis@dielectrics.nl

Spring has arrived, and this morning I read that the vaccine developed in my home town was officially approved in the United States. Let us hope for much more good news to come this year.

This issue of the Magazine contains the first part of an extensive review on composite suspension insulators, a critical review of thermal classes of rotating machines, and an overview of condition assessment and life cycle management of switchgear.

The first article is entitled “Comparative Investigation on Fracture of Suspension High Voltage Composite Insulators: A Review” is the first of two parts, the first part focusing on fracture morphology characteristics. It is authored by Liang Xidong, Li Shaohua, and Zuo Zhou from Tsinghua University; Gao Yanfeng and Lu Yi from State Grid Jibei Electric Power Co.; Wang Jiafu from the National Institute of Metrology in Beijing; Bao Weining from China Electric Power Planning and Engineering Institute; and Wu Chao from the University of Connecticut, US.

This first part of the review is based on research work performed over a period of many years. It presents a comprehensive description of three fracture modes of composite suspension insulators in terms of morphology. The authors point out that compared with many existing ob-ervations, microscopic observations not only emphasize the fracture morphology of individual glass fibers, but also point out that more attention should be paid to the fracture/degradation morphology of the resin matrix and the interface between glass fiber and resin matrix. It is concluded that the comparative investigation approach that was followed allows a better understanding of the similarities and differences of the three known fracture modes of composite insulators, leading to an improved understanding of the process and mechanism of abnormal fracture of composite insulators in actual use. The second article in this issue, authored by Paul C. Gaberson, is entitled “Do the Methods Used to Determine the Thermal Class of Rotating Machine Insulation Systems Make Sense?”. The article provides a historical review of the thermal classes of rotating machines and how they are experimentally determined. Starting with the initial attempts to define standard thermal classes made by Charles Steinmetz and Benjamin Lamme in 1913, the article describes how more knowledge about thermal aging was obtained by pioneers such as V. M. Montsinger and T. W. Dakin, who showed that insulation thermal aging is a chemical process following the Arrhenius reaction rate theory. Based on the theory of thermal aging, tests were developed to determine the actual thermal aging rate. The article further discusses the temperature index of materials versus the thermal class of insulating systems. Finally, the problems with the existing classification method are discussed and potential improvements are suggested. It is concluded that yes, the currently used methods to determine the thermal class make sense, but the users need to be fully aware of the assumptions and compromises made.

The third article is entitled “Switchgear Condition Assessment and Lifecycle Management: Standards, Failure Statistics, Condition Assessment, Partial Discharge Analysis, Maintenance Approaches, and Future Trends,” authored by Aravinth Subramaniam, Sai Srinivas Manohar, Santosh Janaki Raman, and Sanjib Kumar Panda from the University of Singapore and Animesh Sahoo from the University of New South Wales, Australia. In this article, switchgear standards, failure statistics, and condition assessment methods are critically reviewed, with a special focus on medium and high voltage classes. The authors start with a description of common maintenance practice and standards used. Then, the main failures in switchgear are listed, together with a description of their mechanism and characteristics. Failure statistics singling out the most important failure modes are described as reported in different international surveys. A range of condition assessment methods is reviewed, each related to a specific anomaly in the condition of the switchgear. Special attention is paid to some commonly used partial discharge analysis methods. Finally, it is discussed how to arrive at a proper maintenance strategy and which research questions are still unanswered.

John J. Shea

Optical Engineering Science

S. Rolt
John Wiley & Sons Inc.
111 River Street
Hoboken, NJ 07030 http://www.wiley.com
ISBN 978-1-119-30280-3
656 pp., €115 (Hardcover), 2020

This book provides a comprehensive review of optical engineering. It contains a blend of fundamental theory with practical commercial applications that gives the reader the immediate satisfaction of understating the technical operation of many optical devices in use today such as cameras, spectrometers, and telescopes, just to name a few applications. The book also covers many optical engineering equipment and methods used to measure and characterize optical devices and equipment.

The first part of the book covers descriptions of fundamental theory and components and their use in typical optical systems. Some of the items covered include a review of geometrical optics and definitions, apertures and stops, aberrations, and aberration theory, diffraction, radiometry and photometry, and polarization. These are all essential theories and methods that provide the reader with a solid background in optical engineering principles.

Next, optical material are introduced. Fundamental principles of the effects of materials on optical radiation are explained along with coating, filters, prisms, and dispersion devices. Materials are a key parameter for many critical ap- plications, and this section guides the reader toward an understanding of the material effects on optical radiation and how to choose the correct optical materials for an application.

Lasers and laser applications along with optical fibers, waveguides, and detectors are then introduced. One area that may be of particular interest to our readers who work with optical fibers is methods to efficiently couple an optical signal to a fiber optic cable.

Details such as the differences and advantages and disadvantages of various imaging devices such as telescopes and microscopes are useful for anyone contemplating purchasing or building one of these instruments to help with a selecting the type of the intended application. Other devices also described are interferometers, spectrometers, and related equipment. All the fundamental technical details provided on these devices will greatly assist the reader in understating their design and function and provide information for choosing the proper instrument.

Other topics, including the optical lens design process, mechanical modeling, optical component manufacture, system integration and alignment, and optical test and verification, bring together information for developing an entire optical system, not only the optical components. This reference design will help those looking for information or processes on what is involved to develop an overall optical system including recommended design guidelines.

This comprehensive reference volume is written for optical engineers, optical designers, optical systems engineers, and students looking for a design reference that covers a broad range of optical design and optical metrology topics and applications. The book has a dedicated website, accessible with the provided QR code (which may require an account with Wiley to access), that includes problem solutions and spreadsheet tools, making it suitable for a course in optical engineering and a quick way to develop and test your own designs with example spreadsheets already developed.

LPWAN Technologies for IoT and M2M Applications

B.S. Chaudhari and M. Zennaro, Editors
Elsevier
50 Hampshire Street, 5th Floor Cambridge, MA 02139 http://www.elsevier.com/books-and-journals
ISBN 978-0-12-818880-4
445 pp., $125 (Softcover), 2020

Low-power wide area network (LPWAN) is a promising solution for long-range low-power Internet-of-Things (IoT) and machine-to-machine (M2M) communications. The idea of implementing sensors thorough out devices such as instrumentation, electrical networks, or things in remote locations, in which you want to monitor and measure various parameters, allows for autonomous control and predictive maintenance. However, usually, there are resource-limited constraints (e.g., no power sources) for these sensors, which then require a battery and some means of energy harvesting or power supply to charge the battery or power the sensor. This necessitates the need for very-low-powered devices. But even then, the sensors still need a power source, and the longer the transmitting range desired, the higher the power requirements. Batteries have a limited charge life and need to be recharged. LPWAN devices and network architecture are designed to meet these requirements.

This book provides comprehensive coverage of LPWAN and IoT technologies. It focuses on design requirements and constraints; channel access; spectrum management; collisions and interference; energy efficiency, use cases and applications; cyber-security, hardware, and software platforms; issues; and future directions.

Specific topics cover an introduction to LPWAN and network topologies and currently used solutions and design considerations. LoRaWAN (Long-range wide-area network) protocol and challenges of this technology are discussed. The Sigfox radio system, ultra-narrow- band technology, is also introduced. Application topics cover IoT concepts and deployment challenges along with the evolution of M2M communications. Methods for energy optimization are reviewed for LPWAN including energy harvesting (mainly focused on harvesting RF transmission signals) and relaying sensor network used to increase transmitting range without higher power sensor transmitters. Guidelines and criteria for selecting the optimal LPWAN technology are also presented. Other topics include wearable LPWAN devices for remote health monitoring, using LoRa, edge, and fog computing methods for traffic monitoring, cyber-security, and various LPWAN hardware and software platforms currently available.

This book is a very good introduction and easily accessible way to learn about the upcoming technology of LPWAN. It would help teachers, students, researchers, and industry professionals to quickly understand LPWAN technologies, design networks, and deploy IoT applications.

Advances in Modern Sensors: Physics, Design, Simulation and Applications

G. R. Sinha, Editor
IOP Publishing Ltd.
Temple Circus, Temple Way
Bristol, BS1 6HG, UK
Phone: +44 (0)117 929 7481
USA Office:
190 North Independence Mall West, Suite 601
Philadelphia, PA 19106, USA Phone: +01 215 627 0880 http://store.ioppublishing.org
ISBN 978-0-7503-2707-7 143 pp., $159 (eBook), 2020

There are many books on sensors but this one highlights the applications of modern sensors such as wearable sensors, wireless sensors, and cognitive sensors. It presents an introduction and overview of sensors and technologies with an emphasis on modern sensor technology including fundamentals, background, and theoretical concepts of sensors case studies. It covers classification of sensors; some applications of optical sensors; chemical sensors; calibration of optical imaging sensors; wearable sensors; cognitive and biosensors; and sensors used in self-driving cars.

The book begins by introducing a set of definitions for parameters used for describing the properties and characteristics of sensors in general. This information does not seem to apply to any particular sensor and is more of an introduction, but it does not provide any specific information. Classification of sensors follows. Here sensors are generally classified to identify the type of sensor used for a desired application. Also discussed are important attributes such as accuracy versus precision with regard to sensors. The optical sensor sections describe some photo-sensors and optical fibers with a focus on IR sensing and visual imaging. The possibilities of various wearable sensors are described such as sensors for human health assessment, but no specific details on actual sensors are presented. A walking stick for the visually impaired is presented, which uses an Arduino Uno board to illustrate the possibilities of incorporating various sensors in a walking stick intended to help guide the visually impaired. Sensor technology used for self-driving cars provides a general overview that discusses the technology basics and the sensors incorporated in a system but, again, with little design or sensor details.

The book may be of interest to a wide spectrum of readers, such as research scholars, academia, and industry professionals. It is especially for those who employ smart sensors for emerging applications such as robotic arms, cognitive applications, and brain–computer interfaces who may want an overview to gather general ideas for a certain technology that employs modern sensors.

Handbook of Magnetic Materials, Volume 29

E. Bruck, Editor
North-Holland
Radaweg 29, PO Box 211
1000 AE Amsterdam, the Netherlands Distributed by:
Elsevier Inc.
50 Hampshire Street, 5th Floor Cambridge, MA 02139
http://www.elsevier.com/books-and-journals
ISBN 978-0-12-821023-9
213 pp., $385 (Hardcover), 2020

This handbook is part of an on-going series in magnetics; this is the 29th volume in this series. This volume provides updates on select cutting-edge research in magnetics. This particular volume describes three technology areas currently being researched, primarily for the emergent energy transition.

The first of these areas introduces magnetic materials using the concept of spin-orbital torques, originating from the transfer of orbital angular momentum from the lattice to the spin system. This work involves topological insulators and Dirac fermions. Applications envisioned include data storage and the generation of microwaves for wireless communications.

The second class of magnetic materials described covers the effect of magneto-electric coupling between magnetic and electric fields in a material. This effect creates a magnetization of a material proportional to an applied electric field and vice versa. Potential applications include energy transformation, signal generation and processing or information storage. Authors discuss requirements for such materials and the existing challenges and potential processing methods to overcome such limitations in order to realize such applications.

The third topic provides an update on the current state of magnetocaloric materials. The fundamentals for thermodynamics are reviewed as well as the peculiarities associated with magnetic phase transitions in these materials. Envisioned potential applications of these types of materials could include energy efficient magnetic refrigeration.

Although widely accessible, this book is primarily intended for material scientists studying emerging magnetic materials with an interest in the three areas described. The book is highly illustrated with many graphs, tables, and figures summarizing the latest research results in these three areas with accompanying explanations and many references for further study. Those working with these types of materials would certainly find this update of interest.

Contact Lines for Electrical Railways—Planning, Design, Implementation, Maintenance, 3rd Edition

F. Kiessling, R. Puschmann, A. Schmieder, and E. Schneider
Publicis Publishing Erlangen, Germany Distributor:
Wiley-VCH GmbH PO Box 10 11 61, 69451 Weinheim Boschstrasse 12, 69469 Weinheim Germany
Phone: +49 (0)6201/606-0 http://www.wiley-vch.de
ISBN 978-3-89578-420-0
1104 pp., 129 € (Hardcover), 2018

Electric railways use overhead electric lines to provide power to electric trains. These types of trains are very common in much of Europe, parts of Russia, China, and Japan and many other countries but are used in very limited locations in the USA. They are typically found in dense urban areas or used to connect large cities. Typically, overhead lines carry electric current to the railcars to power the system. Both AC and DC systems are used with voltages typically ranging from 750 Vdc to 3 kVdc and 15 kVac to 25 kVac. The previous editions of this book have become worldwide reference standards for contact line engineering including the details for planning, design, implementation, and maintenance of contact lines for electric railway systems.

The authors, active or former Siemens employees or from the Powerlines Group, from Germany and Austria, have extensive experience in contact line technology. This book covers all aspects of contact lines with topics covering the fol- lowing areas: an overview of the electric power systems feeding the electric trains; an introduction to the history of power transmission to railways; all electrical and mechanical aspects of overhead rail design; the interaction between contact lines and pantographs especially at high speed; safety aspects; component descriptions; contact line planning and layout; the construction and maintenance of contact lines; and relevant IEC and Cenelec standards.

This handbook provides a very comprehensive reference source for all aspects of contact lines for electric railways. Because the majority of electrical railways are in countries predominantly using IEC standards and the authors are from Europe, the book focuses on those types of systems, which covers the majority of systems in the world. If you have any involvement or interest in contact lines for electric railways, then this book would be an excellent reference choice that could be used for many years.

Introduction to Simulation Methods for Gas Discharge Plasmas: Accuracy, Reliability and Limitations

I. Rafatov and A. Kudryavtsev IOP Publishing Ltd.
Book Reviews
Temple Circus, Temple Way Bristol, BS1 6HG, UKUS Phone: +44 (0)117 929 7481 USA Office:
190 North Independence Mall West, Suite 601
Philadelphia, PA 19106, USA Phone: +01 215 627 0880 http://store.ioppublishing.org
ISBN 978-0-7503-2360-4 (eBook) 61 pp., $159 (eBook), 2020

This introductory book on numerical modeling methods for gas discharge plasmas is intended to help graduate students and scientists working in the area of computational plasma physics, model plasmas.

Plasma fluid equations, in the drift–diffusion approximation, are derived from the kinetic Boltzmann equation. The essentials of basic modeling approaches (fluid, particle, and hybrid) for gas discharges are described along with details to implement these methods. Some examples of DC and RF glow discharges are given to illustrate the methods. The basics of the finite-difference method and a systematic description of the finite volume method for the numerical solution of the spatially one-dimensional drift–diffusion equation are given. A numerical investigation of nonlinear dynamics and spatial-temporal pattern formation in the gas discharge system with a semiconductor cathode is also presented.

If you model low-pressure (nonthermal) plasmas, this book will provide the fundamental equations that can be used to simulate various aspects of the low-pressure plasma. You will also learn about the physics behind the equations through explanations and graphical plots of results including comparisons between simulations and experimental results. The reader would need a background in plasma physics and some familiarity with Boltzmann’s equation to fully appreciate this book.