A5088047947- High voltage insulation and dielectric phenomena
- Power Transformer Diagnostics and Insulation
- Dielectric materials and actuators
- Thermal Analysis in Power Transmission
- Polymer Nanocomposites and Properties
- Electrical Fault Detection and Protection
- Aerosol Filtration and Electrostatic Precipitation
- Lightning and Electromagnetic Phenomena
- Advanced Sensor and Energy Harvesting Materials
- Electrostatic Discharge in Electronics
- Silicone and Siloxane Chemistry
- Electrohydrodynamics and Fluid Dynamics
- Epoxy Resin Curing Processes
- Infrastructure Maintenance and Monitoring
- Surface Modification and Superhydrophobicity
- Medieval European History and Architecture
- Silicon Carbide Semiconductor Technologies
- Advanced DC-DC Converters
- Historical and Archaeological Studies
- Smart Materials for Construction
- Non-Destructive Testing Techniques
- Electromagnetic Compatibility and Noise Suppression
- Advanced Fiber Optic Sensors
- Polymer Nanocomposite Synthesis and Irradiation
- Microplastics and Plastic Pollution
Catholic University in Ruzomberok
2023-2024
ABB (Switzerland)
2010-2022
University of Leicester
2010
Queensland University of Technology
1999-2003
Delft University of Technology
1993-2002
Vattenfall (Sweden)
2002
Powerlink Queensland (Australia)
2002
Brisbane School of Theology
1999
For a long time, classification of partial discharges was performed by eye, studying discharge patterns at the ellipse an oscilloscope screen. The introduction digital processing techniques allowed automation recognition procedure. These procedures are reported and applied to number actual HV constructions which suffer from discharges. results these tests show that quite satisfactory takes place.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...
An overview of automated recognition partial discharges (PD) is given. The selection PD patterns, extraction relevant information for and the structure a data base are discussed. Mathematical methods useful design examined. Classification interpreted from geometrical point view. Some problems encountered in automation addressed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
The application of three different neural networks (NNs) to the recognition partial discharge (PD) is studied. Results PD measurements on simple two-electrode models, as well models artificial defects in industrial objects, are presented. PDs measured using conventional detection, and patterns processed by previously developed statistical tools. Mathematical descriptors used input for a backpropagation network, Kohonen self-organizing map, learning vector quantization network. All NNs...
Epoxy polymer with micro, nano and micro + silica fillers have been evaluated for their electrical performance in high voltage insulation applications. The dielectric strength of these samples was measured accordance the ASTM D-149 standard. Dielectric spectroscopy used to understand role space charge interfaces materials. results suggest that significant improvement can be expected by using containing nanofillers when compared materials only microfillers. However, measurement showed no...
This work deals with the study of micro and nanosilica filled epoxy resin samples carried out in framework CIGRE WG D1.24 cooperative test program. program focused on chemical, electrical electrostatic properties based nanodielectrics for engineering applications. Epoxy and/or nanoparticles silica were characterized by transmission electron microscopy, dielectric spectroscopy, conduction current space charge measurements. These mutually complementary techniques used to examine effect size...
This article presents the results from round-robin tests performed on epoxy composite materials. These show potential of these materials for use as electrical insulation in some specific applications. A small section addresses health and safety issues related to nanoparticles power engineering industry. We define nanocomposites epoxy-based containing exclusively nanosized filler particles. Epoxy microcomposites are defined microsized particles, micro+nano composites both
The inclined plane tracking and erosion test IEC-60587 is not specified for DC testing. A dc has been developed from the current ac standard three formulations of silicone rubber tested. These materials were tested under voltage levels (2.3, 2.7 3.2 kV) both polarities. Positive tests have highest average peak leakage exhibit a higher degree surface damage. observed degradation pattern heavily dependant on polarity. Consistently in positive cases. Erosion always starts at bottom electrode,...
Traditionally aluminum trihydrate (ATH) is added to high-temperature vulcanized (HTV) silicone rubber for outdoor insulation applications improve flame retardancy and the electrical tracking erosion performance. In this work, flammability of ATH-free HTV formulations were evaluated by UL94 vertical burning test. The most promising candidates, as well reference filled with silica or silica/ATH only, then inclined plane test at 4.5 kV. best result was obtained containing 100 phr 15 melamine...
Epoxy composites with micro, nano and micro + silica fillers have been evaluated for their resistance to corona using point plane electrodes. The experiments were conducted 500 h the surface erosion was measured after every 100 a profilometer. results show significant improvement in of micro+nanofilled samples nanofilled when compared microfilled unfilled materials respectively. emphasize importance good filler dispersion. A model map degradation path filled developed Dijkstra's shortest...
The paper reviews previous work on the DC inclined plane test and suggests equivalent voltage levels in parallel to AC ASTM tracking erosion test. aim of this is provide a basis for standardizing voltage. Round robin tests done five laboratories specimens silicone rubber material were with purpose establishing appropriate ratios by which voltages can be determined respect corresponding voltages. These as 67% 87%, +DC -DC respectively, initial voltage, practical purposes, these are rounded 70 90%.
Power conversion applications in the low voltage (LV) range (≤ 1.2 kV)-such as three-phase inverters-are required to operate at higher efficiencies, ambient temperatures, increasingly smaller form factor, and power density. Up now, most research has focused on voltages up 650 V for printed circuit board (PCB) embedded electronics. This evaluates a novel invertor module based six insulated gate bipolar transistors diodes rated kV 25 A each. unique is compared Semikron MiniSKiiP 23AC126V1....
This work presents further results on the use of fractal features for recognition 3-D partial discharge patterns. Two features, dimension and lacunarity were calculated from patterns their power to discriminate among various was analyzed. The indicate that possess fairly reasonable discriminating abilities.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
This text summarizes the keynote presentation that is based on full-length paper of same title. Dr. Frechette's oral should not be seen as a summary “Brainstorm paper” but glance at some major accomplishments, hinrances and still remaining questions relative to nanodielectrics. Are nanodielectrics “universal” panacea∗? The answer question no — they've got lot potential!
Leakage current magnitude is used as one of the failure criteria in tracking and erosion test IEC 60587. The 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> harmonic also often to identify periods arcing activity. This technique not available for equivalent dc test. paper presents use a machine vision camera alongside measurements leakage discharge activity during testing so enable determination arc intermittency. simple image...
The present IEC 60587 standard needs several improvements which would help manufacturers of power equipment and material suppliers to assess outdoor polymeric materials in a more reliable way.
Epoxy-based systems are used widely as dielectrics in electrical applications and, such systems, the chosen stoichiometry is important determining nature of molecular network that forms hence, physical properties final system. However, inclusion nanoparticles with large interfacial areas into epoxy may introduce additional chemical reactions between moieties on nanoparticle surfaces and reactants, or alter rate sequence various pathways occur during curing, consequence cross-linked within...
A situation involving a polymer nanocomposite containing large amount of inorganic filler was studied. An epoxy with content 20% wt nanosilica used. Emphasis put on imaging at the nanoscale and some dielectric responses were measured using spectroscopy. Using Transmission Electron Microscopy (TEM) in High-Angle Annular Dark Field (HAADF) scanning mode, an area less than 4 nm around isolated particle imaged found to have very low atomic number. With Atomic Force (AFM) peak-force mode...
This text summarizes the keynote presentation that is based on full-length paper of same title. Dr. Fréchette's oral should not be seen as a summary "Brainstorm paper" but glance at some major accomplishments, hinrances and still remaining questions relative to nanodielectrics. Are nanodielectrics "universal" panacea <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∗</sup> ? The answer question no — they've got lot potential!
In this paper the effect on dc and ac electrical properties of silica nano micro particles dispersed in epoxy resins is discussed. particular, space charge, conductivity, dielectric strength partial discharge resistance analyzed. The results show that nanostructured materials exhibit smaller charge accumulation with respect to both base microfilled materials. Regarding PD resistance, + filled display longer lifetimes resin including nanofillers or microfillers alone.
This paper describes the results of experiments made to examine nature discharge phenomena between water drops on polymer surfaces. Small samples high temperature vulcanised silicone rubber were subjected electric stress and exposed clean salt fog. The resulting surface activity was observed with a high-speed video camera. Water found vibrate in variety ways pushed away from regions low regions. distribution appeared follow equipotential lines electrodes. grew larger by absorbing droplets...
A brand new phenomenon, namely, electrical conduction via soliton-like ultra fast space charge pulses, recently identified in unfilled cross-linked polyethylene, is shown for the first time to occur insulating polymer nanocomposites and its characteristics correlated with electromechanical properties of nanostructured materials. These pulses are observed cross insulation under low field epoxy-based containing nanosilica particles relative weights 1%, 5%, 10%, 20% at speeds orders magnitude...
Material samples were prepared consisting of silica particles in an epoxy matrix. The generic compound contained a large amount micrometric (e.g. 60% wt.) and few % nanosilica. Investigation the microstructure showed that indeed microcomposites exhibited nanostructured morphology. Dielectric spectroscopy was used to compare behavior materials differing composition. Posttreatment using heat necessary obtain reproducible dielectric response. features linked material compositions annotated. For...