With regard to the discussion on d.c. versus a.c. for dielectric withstand testing, I thought I would share this book review. The book appears to cover the issues raised in the emc-pstc discussion. Mr. Shea, the reviewer, is with Eaton Corporation, Moon Township, Pennsylvania, U.S.A. Product safety professionals should understand the physics of insulation breakdown rather than relying on "conventional wisdom" which so often exists in the field of product safety. I'll see if I can find it in a technical library, and check it out before I fork over $100 for the book. Richard Nute Product Safety Consultant Vancouver, Washington, U.S.A.
Review by John J. Shea, Insulation Magazine November-December 2011 High Voltage and Electrical Insulation Engineering by R. Arora and W. Mosch John Wiley & Sons Inc. 111 River Street, 8-01 Hoboken, NJ 07030-5774 Phone: (800) 762-2974 Fax: (800) 597-3299 http://www.wiley.com ISBN 978-0-470-60961-3 393 pp., $99.95 (Hardcover), 2011 Electrical insulation is essential for power systems. To create an optimally designed insulation system that provides long-term life, it is crucial to understand the behavior of dielectric materials under electrical stress. Generally, the higher the potential, the greater the level of insulation required. To successfully design power systems, the high voltage engineer must understand the fundamentals of high voltage engineering and the behavior of dielectrics subjected to high fields. There are not many new books published in this area of research, making this one a very welcome addition to the technical literature. The contents of this book are from lectures in high voltage engineering given by the authors at the Technical University at Dresden, Germany, and at the Indian Institute of Technology, Kanpur, India. The book is organized by insulating material (gases, liquids, and solids). It begins by describing electric fields and how they are influenced by electrode shape. Much of this material is similar to that found in a book on electro magnetics and is useful for laying the foundation of understanding of electric fields in general. The section on gases, the largest section of the book, predominantly covers breakdown processes of various gases, with major focus on the two most widely used gas insulators-air and SF6. Different types of corona discharges (star, streamer, and leader) are described including breakdown processes for a wide variety of conditions-uniform fields, weakly nonuniform fields, extremely nonuniform fields, effect of wave shape, and the effects of partial breakdown. Electric arc properties such as the V-I characteristics in air are also covered. Gas insulated systems are also described in detail including the important aspect of particle movement within the gas insulated system. Gaseous breakdown is continued with long arcs in air (i.e., lightning). A review of lighting mechanisms is presented along with information on the lightning strike process, the effects of lightning, and some lightning protection methods. This section ends with some superficial accounts of ball lightning. Next, a short section on vacuum insulation covers vacuum breakdown processes in general and more specifically vacuum interrupter bottles, including topics on arc interruption, delayed reignition of arcs, and the effects of the insulator surface roughness and area on breakdown. Next are liquid dielectrics and their classification, properties, and breakdown characteristics with a focus on mineral oils for transformers, halogen free synthetic oils, and chlorinated diphenyles. The effects of time on polarization under de and ac conditions along with practical breakdown strength measurements showing the important effects that moisture and temperature can have on the breakdown of oil are also covered. The last section deals with solid dielectrics and their sources, properties, and behavior in electric fields. First, the authors classify the solids into inorganic (ceramics and glasses) and polymeric organic materials (thermoset, thermoplastic, and composites). The classical breakdown mechanisms (intrinsic and thermal) are covered along with partial breakdown (i.e., partial discharge) mechanisms. Even though breakdown results can vary greatly depending on material preparation and test conditions, it is unfortunate that there is little measured breakdown data given on the solids described. Even though much of this book is covered in other books, the reader can use this book for gaining a quick understanding of breakdown phenomena in different materials and devices. It is an up-to-date reference book on the fundamentals of dielectric breakdown phenomena that will surely be used by students and researchers for many years to come. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://product-compliance.oc.ieee.org/ Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
