IEEE Electrical Insulation Magazine May/June 2026 Back Cover

IN the Special Issue, we are proud to present the expanded versions of selected papers presented at the 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV). It was held at Suzhou, China, from September 18 to 23, 2016. The International Symposia on Discharge and Electrical Insulation in Vacuum (ISDEIV) is a non-profit, international organization whose purpose is to encourage the advancement of the science and application of electrical insulation and discharges in vacuum, primarily by conducting symposia for the exchange of scientific information. The symposia are held biannually (even-numbered years). The symposia are interdisciplinary meetings for the exchange of results, presentation of progress, and discussion of ideas and challenges for the future in the field of electrical discharges and insulation in vacuum. Both fundamental and applied aspects are covered. Symposia program consists of invited talks, invited oral contributions, and posters. Mini-courses and informal discussions on relevant topics may also be offered in addition to the regular Symposium schedule.

Our research as well as others has shown that micro-void content in electric insulation polymers grows in a way that can be correlated to the degree of aging. Specific results of our experiments combined with research by others have led us to conclude that a promising technique for predicting remaining life in electric cable insulation, based on micro-void content and proximity to void limiting parameters, can be developed. This approach involves use of acoustic or optical microscopy to establish an estimate of void content in polymers by determining micro-void sizes and density. Separate research is used to establish limiting values for percent void content correlating to material failure. The mode of failure varies depending on the applied voltage regime. For example, at medium and high voltage levels, partial discharge detection can be considered indicative of pending end of life. Whereas for low voltage regimes, brittleness to the point of cracking susceptibility would allow the potential for moisture ingress and shorting and can be considered end of life. It has been separately shown that void growth rate is a function of temperature and radiation dose rate both during normal and nuclear accident conditions and is predictable based on the known polymer chemical degradation equations, which produce gaseous products in the form of oxygen, water vapor, carbon dioxide, and carbon monoxide. Thus if end of life void content is known, the degree of void content growth occurring during a design basis accident is properly accounted for, and void content growth rates during normal temperature and radiation conditions are considered, then remaining life in electrical insulation can be accurately predicted. In recent years, several techniques have been proposed to assess electrical insulation aging. One of the more promising approaches for use with medium voltage cable is the tan-delta technique. This paper will demonstrate how the mirco-void content approach can be used to validate other techniques such as tan-delta and add additional meaning and value not otherwise available from tan-delta alone.

Fusion reactor design with ceramics

Natural two-dimensional pyrophyllite: Nanoscale lubricant, electrical insulator and easily-machinable material

The More Electric Aircraft (MEA), complete with the More Electric Engine (MEE) is a concept that has been introduced by aircraft and engine manufacturers to reduce the reliance on hydraulic and pneumatic systems while reducing fuel costs. However, these concepts have brought a requirement to increase system voltage which in turn challenges electrical insulation systems. The insulation system must withstand these higher voltages in more severe conditions such as the high temperature environment present in the engines. Electrical machines are critical on the more electric aircraft and the reliability of these machines must be high while the weight and volume are constrained. For MEE high temperature applications (up to 450°C), inorganic materials will be used as wire insulation since traditional organic materials cannot withstand such high temperature. Although inorganic insulation materials have been used for extended periods in other high voltage applications, their electrical behavior are not fully understood especially as part of aerospace electrical machine insulation system. This paper will detail the results of initial testing that seeks to understand the basic electrical performance of three inorganic wire candidates. The results will be used as a benchmark for further tests in order to evaluate critical ageing mechanisms for inorganic electrical machine insulation systems used in an aerospace environment. The performance of the electrical insulation used in all candidate wires is presented and compared. SEM scanning has been performed to examine differences in the insulation layer structures of the materials. Analysis has then been based on both measurement data and scanning results. All the tests have been performed before and after a limited number of thermal cycles and at the low pressure conditions i

Room temperature vulcanized (RTV) silicone rubber filled with aluminum trihydrate (ATH) is substantially engaged in electrical outdoor insulation applications. The pristine silicone rubber is highly combustible. ATH filled silicone rubber offers excellent electrical insulation but lacks in providing adequate flame retardancy. This short communication reports the novel results on improved flame retardancy of pristine and ATH filled silicone rubber whilst retaining the electrical insulation properties to a great extent. Results suggest that the presence of only one percent of graphene nanoplatelets with ATH sharply reduces the heat release rate and rate of smoke release. A minor reduction in dielectric breakdown strength and volume resistivity is noticed. Furthermore, permittivity and dielectric loss at power frequency suggest that a marginal 1% concentration of nanoplatelet with ATH is an excellent approach to fabricate flame retardant silicone rubber with an acceptable electrical insulation level.

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I am greatly honored to have been chosen by the High Temperature Materials Division of the Electrochemical Society to receive their Outstanding Achievement Award for 2016. For this lecture, I will give a brief review of who I am, my career in teaching, my research interests in both insulating and electrical conducting oxides and focus on what I perceive as my major contributions to the world of ceramics (high temperature materials). Ceramics are well-known for their ability to serve as electrical and thermal insulators, structural components and for corrosion protection. In addition, their unique ability to interact with electric and magnetic fields yields properties that can vary many orders of magnitude. These include the dielectric permittivity, electrical conductivity, piezoelectricity, magnetic susceptibility, and magneto-and electro-optics. With these variety of properties, the use of ceramic components is so vast that it includes most of the devices, which we encounter and use every day.For example, the electrical insulating properties allow use of materials such as alumina for substrate in integrated circuits as well as high voltage insulators (e.g. computers. spark plugs, TV). Electrical energy storage capabilities have allowed ceramic materials to be integral parts of electronic circuits. Both require active component isolation as well as local power supplies which capacitors provide (e.g. TV, computers, cell phones). High electronic conductivity allows ceramics to be used as electrodes as well as resistors for a wide range of applications. Piezoelectric properties allow ceramics to serve as transducers for many everyday applications (e.g. ultrasonic imaging and smoke detectors]. The ability of zirconia to display high oxygen conductivity has enabled a rapidly growing list of applications such as oxygen sensors (every automobile has one), oxygen separations membranes and electrolytes for solid oxide fuel cells.All of these applications of ceramics are perfect examples where understanding the structure-property relationships at multiple scale levels were a key necessity for success. Amongst the crystallographic symmetries which have yielded the most varied properties, the perovskite system reigns supreme. I have dedicated my research career to this system and explore the influence of composition and defect structure on both electrical insulating and conducting systems. I first will discuss the properties and characteristics of this unique class of ceramics which allows them to be utilized both as electrical insulators as well as electrical conductors. I will then give some examples in which the properties are tailored to meet requirements of specific applications: capacitors, solid oxide fuel cells, and sensors.

Electrical and thermal insulation via an oxidized, rough contact interface for the electro-thermal actuation of carbon nanotubes

Fusion reactor design with ceramics

He II heat transfer through superconducting cables electrical insulation

The main aging mechanism of electrical cables with polymeric electrical insulation is the growth of water trees. Water trees are initiated if the relative humidity (RH) in the electrical insulation is above a critical level. Delaying the water ingress into the electrical insulation system delays the water tree initiation and reduces water tree growth, thus extending the service life of the cable. For a cable without any metallic water barrier, the water ingress can be significantly delayed by the use of an outer sheath material with low water permeability. An even greater delay in the water ingress into the electrical insulation can be achieved using a layered sheath system. To explore the possibilities of a layered sheath system, calculations of water ingress into a typical cable cross section has been performed using a finite element method. The water diffusion and sorption data used in the calculation has been measured for typical cable materials. Calculations have been performed for uniform temperature conditions and for a temperature gradient due to resistive current heating. The time to reach critical humidity levels and stationary humidity levels in the insulation system has been determined for several different arrangements of the sheath system. A sheath system with an outer layer of a material with low water permeability and an inner layer of a material with a high water absorption capacity is shown to give a significant delay of the water ingress into the electrical insulation. For the sheath materials used in this study, there is an optimum distribution of thickness of each layer. The calculations also show that a temperature gradient across the insulation system of a cable in operation gives an advantageous RH profile. With a temperature gradient the equilibrium RH level in parts of the electrical insulation can be lower than the critical value for water tree initiation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

This work is devoted to analyze the alternating dielectric current flows through polymeric materials used in electrical cables insulation. The insulating compound based on poly (vinyl chloride) (PVC/B), used as electrical insulation in medium and low voltage cables manufactured by the electric cables factory CABEL of Algiers (Algeria), was chosen as the studied material. Accelerated thermal aging on circular shaped samples of PVC/B was performed at two temperatures, 80°C and 120°C, during 2016 hours (84 days). Spectral analysis of the obtained current waveform parameters, such as magnitude and harmonic content as indicated by the total harmonic distortion (THD), were analyzed using fast Fourier transform (FFT) method at different stages during aging time and for five levels of AC applied voltage, ranging from 3 kV to 15 kV. Through this work, the study of the current waveforms offers significant information about the degradation level of the material, which can be used for the diagnostic of electrical cables.

The corrosion behavior of TiAlN coatings prepared by PVD in a hydrofluoric gas atmosphere