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Energy conversion and conditioning technologies, power electronics, adjustable speed drives and their applications, power electronics for smarter grid, energy efficiency,technologies for sustainable energy systems, converters and power supplies
APEC focuses on the practical and applied aspects of the power electronics business. Not just a power designer’s conference, APEC has something of interest for anyone involved in power electronics including:- Equipment OEMs that use power supplies and converters in their equipment- Designers of power supplies, dc-dc converters, motor drives, uninterruptable power supplies, inverters and any other power electronic circuits, equipments and systems- Manufacturers and suppliers of components and assemblies used in power electronics- Manufacturing, quality and test engineers involved with power electronics equipment- Marketing, sales and anyone involved in the business of power electronic- Compliance engineers testing and qualifying power electronics equipment or equipment that uses power electronics
Electrical Materials, Equipment, Testing, Nanotechnologies, Power Systems, Motors, Generators, Transformers, Switchgear
1. Ageing and life expectancy of HV insulation;2. Bio-dielectrics;3. Conduction and breakdown in dielectrics;4. Dielectric materials for electronics and photonics;5.Dielectric phenomena and applications;6.Dielectrics for superconducting applications;7.Eco-friendly dielectric materials;8.Electrical insulation in high voltage power equipment and cables;9.Electrical and water tree development and surface tracking;10.Gaseous electrical breakdown and discharges;11.HVDC insulation systems;12. Nano-technology and nano-dielectrics;13. New functional dielectrics for electrical systems;14. Partial discharges;15.Space charge and its effects;16. Surface and interfacial phenomena.
A: BREAKDOWN AND FLASHOVERA1. Vacuum breakdown and pre-breakdown phenomenaA2. Surface discharges and flashover phenomenaB: VACUUM ARCSB1. Switching in vacuum and related phenomenaB2. Interaction of vacuum arcs with magnetic fieldsB3. Vacuum arc physicsB4. Computer modeling and computer aided designB5. Pulsed power physics and technologyC: APPLICATIONSC1. Vacuum interrupters and their applicationsC2. Surface modification and related technologiesC3. Electron, ion, neutron, X-ray and other beam and light sources
Experimental and theoretical advances in antennas including design and development, and in the propagation of electromagnetic waves including scattering, diffraction and interaction with continuous media; and applications pertinent to antennas and propagation, such as remote sensing, applied optics, and millimeter and submillimeter wave techniques.
Contains articles on the applications and other relevant technology. Electronic applications include analog and digital circuits employing thin films and active devices such as Josephson junctions. Power applications include magnet design as well asmotors, generators, and power transmission
Electrical insulation common to the design and construction of components and equipment for use in electric and electronic circuits and distribution systems at all frequencies.
This publication covers the theory, design, fabrication, manufacturing and application of information displays and aspects of display technology that emphasize the progress in device engineering, device design, materials, electronics, physics and reliabilityaspects of displays and the application of displays.
The magazine covers theory, analysis, design (computer-aided design), and practical implementation of circuits, and the application of circuit theoretic techniques to systems and to signal processing. Content is written for the spectrum of activities from basic scientific theory to industrial applications.
2018 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), 2018
Extruded high voltage direct current (HVDC) cable with cross-linked polyethylene (XLPE) insulation is a key power device which has been widely used globally due to its advantages. However, there are many challenges in the development of HVDC XLPE cable. One of the issues in design and operation is the DC conductivity of XLPE material, which could be affected by crosslinking ...
2013 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2013
The non-standard lightning impulse voltages have variable front time, duration time and may have high-frequency components superimposed on the waveforms due to the reflection in the substation and other factors. These surges can propagate to the transformer winding and may even lead to the breakdown of the winding insulation. To maintain the high reliability in insulation performance of the oil-immersed ...
2017 IEEE 19th International Conference on Dielectric Liquids (ICDL), 2017
Though the ultrahigh voltage-class (UHV-class) transformers have been increasingly used, the increased entrance capacitance always makes it difficult to generate the standard lightning impulse (SLI) in the lightning impulse withstand voltage test. To verify the equivalence of other impulse voltage waveforms and provide basis for the revision of corresponding standards, the dependence of the dielectric strength of typical insulation structures ...
2018 12th International Conference on the Properties and Applications of Dielectric Materials (ICPADM), 2018
High voltage direct current (HVDC) extruded cables are developing rapidly in the last two decades and cross-linked polyethylene (XLPE) has been the preferred insulation material worldwide. The central issues in design and operation of HVDC XLPE cables are the space charge and DC conductivity characteristics, which rely on crosslinking byproducts within the insulation. Degassing process during HVDC extruded cable manufacture ...
2013 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2013
The stator insulation system of offshore wind turbine generator (WTG) will be subjected to marine environment, such as high humility and heavy salt fog. In order to study its resistance to this hostile environment, the marine environmental conditions in the coast regions along China's coastline have been firstly examined in this paper. The specimens for modeling stator insulation system of ...
Extruded high voltage direct current (HVDC) cable with cross-linked polyethylene (XLPE) insulation is a key power device which has been widely used globally due to its advantages. However, there are many challenges in the development of HVDC XLPE cable. One of the issues in design and operation is the DC conductivity of XLPE material, which could be affected by crosslinking byproducts within the insulation. In this paper, the influence of crosslinking byproducts on the distribution and the evolution of DC conductivity of HVDC XLPE cable insulation is investigated. The content of crosslinking byproducts was obtained by Fourier transform infrared spectrum (FTIR) method and DC conductivity was measured with 20, 30 and 50 kV/ mm electric stress at 30 °C. It is found that the content of cumyl alcohol, a-methyl styrene and acetophenone exhibits spatial distribution in the insulation layer and varies with the degassing process. The byproduct content of inner insulation is in the highest level, and acetophenone decreases most significantly during the degassing. Affected by this, the conductivity demonstrates corresponding distribution profile in different insulation positions which is consistent with the byproducts distribution. The variation of conductivity during the degassing process is in accord with the decrease tendency of acetophenone, since it will greatly affect the ionic conduction in insulation. Besides, crosslinking byproducts are taking effect combined with some other factors, for instance crystallinity, degree of crosslinking of XLPE material, as well as cable construction. It is concluded that the DC conductivity of HVDC XLPE cable insulation is affected by multiple factors, and conductivity design and operation issues should be considered comprehensively related to the construction and manufacturing process of HVDC XLPE cable.
The non-standard lightning impulse voltages have variable front time, duration time and may have high-frequency components superimposed on the waveforms due to the reflection in the substation and other factors. These surges can propagate to the transformer winding and may even lead to the breakdown of the winding insulation. To maintain the high reliability in insulation performance of the oil-immersed transformer and offer reference to the design of the insulation in the transformers, it is necessary to obtain the oil-paper insulation characteristics under non-standard lightning impulse voltages (non- standard LIWs). In this paper, two electrode models are established to simulate the insulation configuration of windings in oil-immersed transformers. The experiments were carried out on the breakdown characteristics of the electrode model in oil. The breakdown voltages of oil- paper insulation for different front time of impulses, oil-gap distance and insulation structure were measured and then compared with the breakdown voltages under standard lightning impulse waveform (SLIW). In the examined range, the dielectric breakdown values under steep front non-standard lightning impulse waveforms were much higher than those under standard lightning impulse waveforms in all cases. Breakdown voltage of turn-to-turn model under oscillating lightning impulse waveform (OLIW) is much higher than that under SLIW. The experiment results clearly showed that the same insulation structure could withstand higher steep front non-standard LIWs and OLIWs, and these findings may offer a reference to clarify the insulation margin between non-standard LIWs or OLIWs and SLIWs.
Though the ultrahigh voltage-class (UHV-class) transformers have been increasingly used, the increased entrance capacitance always makes it difficult to generate the standard lightning impulse (SLI) in the lightning impulse withstand voltage test. To verify the equivalence of other impulse voltage waveforms and provide basis for the revision of corresponding standards, the dependence of the dielectric strength of typical insulation structures in oil-immersed transformer on impulse voltage waveform is studied. The turn-to-turn insulation model and the oil-pressboard insulation model were utilized, characterized as the common insulation structures. The front time and the tail time of impulses varied from 0.07 to 2.6 μs and 3 to 300 μs, respectively. Breakdown characteristics of these two insulation models under different impulse voltages were acquired through experiments. The results show that, no matter what the insulation model used, an increase either in front time or tail time decreases the 50% breakdown voltage. On the basis of the experimental results, discussions are made on the time related breakdown processes and the fungibility of SLI.
High voltage direct current (HVDC) extruded cables are developing rapidly in the last two decades and cross-linked polyethylene (XLPE) has been the preferred insulation material worldwide. The central issues in design and operation of HVDC XLPE cables are the space charge and DC conductivity characteristics, which rely on crosslinking byproducts within the insulation. Degassing process during HVDC extruded cable manufacture can efficiently reduce the crosslinking byproducts content. In this paper, the effects of degassing duration on space charge behavior and DC conductivity property in cable insulation are investigated. The space charge accumulation and DC conductivity are measured with 30 and 50kV/mm electrical stress at room temperature. It is found that hetero-charges accumulate near both electrodes in undegassed specimens, while in the preliminary stage of degassing process the amount of accumulated charges decreases and increases in the later stage. DC conductivity changes in a similar way as the space charge results. For a certain degassing time, the inner insulation layer has more charge accumulation and higher conductivity compared to middle and outer insulation layers. It can be concluded that space charge characteristics and conductivity property are first improved by degassing process and then degraded somewhat with longer degassing time; and the degassing effect of outer insulation layer is better than that of inner insulation layers. More studies should be done to find out the reasons for space charge and DC conductivity changes with degassing duration, as well as the mechanisms of the migration of crosslinking byproducts in thick insulation layer in cables.
The stator insulation system of offshore wind turbine generator (WTG) will be subjected to marine environment, such as high humility and heavy salt fog. In order to study its resistance to this hostile environment, the marine environmental conditions in the coast regions along China's coastline have been firstly examined in this paper. The specimens for modeling stator insulation system of 5MW/3kV class offshore wind turbine generator were prepared. The environmental tests, including the change of temperature, steady damp heat and salt mist, have been carried out. At each interval of periodic tests, some nondestructive diagnoses such as dissipation factor and insulation resistance have also been carried out to monitor the change. After the simulated marine environmental test of 4 periods, the residual breakdown voltages of specimens were measured and the micro-structures of insulating material were observed by microscope. The test results show that, even though micro-cracks have been generated on the interface between the coil main insulation and the iron core, and resulted in the brine permeated into the inner surface of the core slot, the dielectric properties of insulation system of the specimens still kept in the range of normal specifications. The insulation system of specimen has performed an excellent resistance to the marine environment due to the electrical shielding effect of the semi- conductive slot coating.
HVDC transmission has been adopted widely for its large energy transport capacity, high stability and more economical in long-distance power transmission. Converter transformer is the key equipment in HVDC transmission system. The insulation of converter transformer valve side endures a composite voltage including AC, DC and pulsating component etc. Partial discharge (PD) occurring in a void surrounded by insulating material is believed to be one of the main causes of insulation breakdown and it is the main factor of electrical aging of materials. Therefore, it is important to recognize the prebreakdown phenomena and to evaluate the lifetime of insulating materials. Much research has been carried out to study the partial discharge characteristics under pure AC or DC voltage. Only a few investigations were focused on composite voltage. In order to obtain more understanding of PD characteristics under composite voltage, the PD detection and analysis of oil- pressboard insulation under pulsating DC voltage waveform are studied in this paper. The voltage waveform of converter transformer is analyzed through computer simulation. A 6-pulse DC voltage generator and PD detection system are set up. Influence of the DC component and pulsating component to the PD characteristics is studied in lab test. The experimental results show the DC component and pulsating component affect the PD inception voltage, but the pulsating component has more significant influence to PD characteristics than DC component. The study provides an experimental foundation for the converter transformer insulation breakdown mechanism analysis.
The procedure for selection of the withstand voltages for equipment phase-to- ground and phase-to-phase insulation systems is specified. A list of standard insulation levels, based on the voltage stress to which the equipment is being exposed, is also identified. This standard applies to three-phase ac systems above 15 kV.
Fundamental insulation characteristics of high-pressure CO<sub>2</sub> gas for gas-insulated power equipment - effect of coating conductor on insulation performance and effect of decomposition products on creeping insulation of spacer -
Currently, environmental problems such as global warming are important issues, and SF6 has been identified as a greenhouse gas with a long atmospheric lifetime. Therefore, in the long term, it is preferable to reduce the amount of SF6 used as an insulating gas. It is thus important to discuss the possibility of using more environmentally friendly gases as alternative insulation for gas-insulated apparatus. In this paper, we describe the fundamental insulation breakdown characteristics of high-pressure CO2 gas at gas pressures of up to 1.0 MPa under simulated practical conditions, including the insulation breakdown characteristics of a high-voltage conductor with an insulating coating and the effect of decomposition products on the creeping insulation of a spacer. With the aim of enhancing insulation performance, we discuss the effect of the type of insulating coating on insulation performance. The breakdown electric field was increased by 20% by coating the conductor. It was verified that the application of an insulating coating is a practical method for enhancing the insulation performance of high-pressure CO2 gas. It was also verified that the decomposition products have only a slight effect on the creeping insulation of the spacer except for when there is heavy pollution on the insulating spacer. However, if a large amount of decomposition products is expected to be deposited on the insulating spacer during operation, which may cause a severe interruption to the current, it will be necessary to consider this factor in the insulation design.
Solid insulation tended to absorb moisture during the operation and maintenance of oil-immersed transformers, which could be dangerous to the apparatus especially under rated conditions. As had been researched, wet insulation could lead to bubble effect in turn-to-turn insulation when the temperature in transformer increased rapidly. Primarily, this paper investigated the degradation of dielectric strength caused by gas bubbles generated from oil-paper insulation. This paper mainly focused on clarifying the evolution of thermal bubble formation. The experimental platform consisted of an oil-paper insulation system, and an adjustable heating system was established to study the influence of water and gas content on bubble evolution temperature. Results showed that the gas content and moisture content in the paper could significantly affect inception temperature of bubble formation, which could well explain the high probability of bubble evolution in old and wet oil-impregnated transformers. Then, a mathematical model was founded to calculate the bubble evolution temperature considering the solubility of gas and moisture in transformer oil at a certain temperature. Finally, based on the above results, this paper provided a strategy for managing the risk of insulation failures in oil-immersed transformers caused by thermal bubbles in dynamic rating conditions.
This guide applies to mineral oil used in transformers, load tap changers, voltage regulators, reactors, and circuit breakers. The guide discusses the following: a) Analytical tests and their significance for the evaluation of mineral insulating oil. b) The evaluation of new, unused mineral insulating oil before and after filling into equipment. c) Methods of handling and storage of mineral insulating ...
This guide recommends tests and evaluation procedures, as well as criteria and methods of maintenance for less Flammable hydrocarbon transformer insulating fluids.
This guide recommends tests and evaluation procedures, as well as criteria and methods of maintenance, for natural ester-based transformer insulating fluids. These base fluids are also known as vegetable seed oils. Methods of reconditioning natural ester-based insulating fluids are also described. Where instructions given by the transformer or fluid manufacturer differ from those given in this guide, the manufacturer’s instructions ...
Electrical Engineer - Laser and Experimental Systems
Lawrence Livermore National Laboratory
Lead Electrical Engineer/Applied Physicist
Lawrence Livermore National Laboratory