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Electrical Insulation, IEEE Transactions on

Issue 2 • Date April 1982

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Displaying Results 1 - 20 of 20
  • IEEE Transactions on Electrical Insulation

    Page(s): c1
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    Freely Available from IEEE
  • IEEE Electrical Insulation Society

    Page(s): c2
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    Freely Available from IEEE
  • Corona and Non-Spark Discharges

    Page(s): 89
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    Freely Available from IEEE
  • Corona and Insulation

    Page(s): 90 - 105
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    The aim of this paper is to review our present knowledge of the physics of electrical coronas and their interaction with surfaces, with some emphasis on phenomena which seem of importance for high voltage insulation. We will concentrate on fundamental and general subjects, in order to limit the scope of the paper and to make it serve as an introduction to the more specialized papers that follow. View full abstract»

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  • Mechanisms for Inception of DC and 60-Hz AC Corona in SF6

    Page(s): 106 - 120
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    Using a pulse counting technique, inceptions of positive and negative point-plane corona in SF6 under dc and 60-Hz ac conditions were measured. Effects of gas pressure, UV-radiation, and point electrode size on differences between ac and dc, and between positive and negative inceptions were investigated. Inceptions were also calculated using the streamer criterion. Agreement was obtained with measured negative inceptions for both ac and dc conditions, but not with positive inceptions. The growth in the active-electron initiation volume with applied voltage was calculated and used to explain the observed polarity effect. The magnitude of the polarity effect is predictably reduced, either by irradiating the gap or by increasing the diameter of the point electrode. The difference between ac and dc positive inceptions is attributed to the enhancement of avalanche-initiating electron production by the residual ion space charge from negative corona in the previous half-cycle. Without radiation, it is hypothesized that electron initiation for positive corona occurs mainly via field-enhanced collisional detachment of negative ions, the probability of which depends on the degree of field nonuniformity in the gap. For negative corona, initiation is assumed to occur via field emission from the point electrode. The presence of radiation enhances initiation in the positive case by photodetachment of negative ions, and in the negative case by photoelectric emission. View full abstract»

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  • Pulsed Glow Discharges in Laser Excitation and Breakdown

    Page(s): 121 - 124
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    The spatiotemporal development of discharges in uniform field gaps has been studied for many years in order to understand the physical mechanisms of breakdown. These studies have shown that a glow discharge structure is produced as an intermediate stage in the breakdown process which finally leads to the formation of a filamentary arc. Recently these pulsed or transient glow discharges have been used to pump a wide variety of gas lasers including CO2 lasers and rare gas-halide excimer lasers. Preionization of the gas volume is usually used to ¿stabilize¿ these laser glow discharges, i.e. to increase the duration and/or energy density of the pulsed glow discharge and delay the onset of arc formation. Recent experimental work also has shown that the corona discharges which are observed in point-plane gaps have a glow discharge-like structure. These two types of discharges are compared and some speculations are offered about the ¿corona stabilization¿ process in point-plane gaps and its relationship to arc formation in uniform field gaps. View full abstract»

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  • Corona-Generated Space Charge Environment in the Vicinity of HVDC Transmission Lines

    Page(s): 125 - 130
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    Corona discharges occurring on HVDC transmission lines generate ionic space charges which fill the entire interelectrode space between the high-voltage conductors and the ground plane. In the case of unipolar lines, the polarity of the space charge will be the same as that of the conductor, while in the case of bipolar lines, space charges of both polarities mix in the region between the two conductors. The space charges drifting between the conductors and ground may produce electric induction effects on objects and people located under the lines. With the prospect of increased use of HVDC lines for purposes of long-distance bulk-power transmission, both theoretical and experimental studies are presently under way in order to clarify any possible effects and thus help in the proper design of the transmission lines. The physical mechanisms involved in the generation of the space charge environment as well as the production of any possible induction effects will be discussed. The State of the ARt of the theoretical analysis of dc ionized fields will be described. Finally, the problems of instrumentation and measurement techniques will be discussed and the practical measurement experience accumulated to date will be reviewed. View full abstract»

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  • Pre-Breakdown Discharges in Highly Non-uniform Fields in Relation to Gas-insulated Systems

    Page(s): 131 - 142
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    In clean SF6 gas-insulated power transmission systems significant pre-breakdown discharges are rarely observed. This is so because the prevailing electric field is only moderately non-uniform. In practical systems, however, conducting particle contamination creates regions of highly non-uniform fields. Initial ionization, under contaminated conditions, takes the form of pre-breakdown discharges. An understanding of pre-breakdown discharges is essential for evaluating the conducting particle effects and the insulation capability of SF6 gas-insulated systems. Rod-to-plane gaps provide a convenient way of studying pre-breakdown discharges in SF6 under highly non-uniform fields under controlled laboratory conditions. The relatively few published reports of investigations of prebreakdown discharges in SF6 are reviewed. Based on the authors' and other published experimental results, several pre-breakdown regimes (for example, single pulse and multiple pulse pre-discharges and incomplete breakdowns etc.) are identified. The randomness of the time delay of the first pre-discharge current pulse is attributed to the rate of production of initiatory electrons near the anode and the growth of electron avalanches thus generated. The importance of the spatial electric field distribution around the rod electrode (anode) is emphasized. Since in practice transient overvoltages may be superimposed on the system 60 Hz ac voltage, the effect of continuous corona and the space charge due to the 60 Hz ac voltage on the overall insulation performance of SF6 gas-insulated systems under combined ac and impulse voltages also is discussed. View full abstract»

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  • Fundamental Limitations in the Measurement of Corona and Partial Discharge

    Page(s): 143 - 150
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    The theoretical sensitivity of conventional partial discharge detectors is compared with that obtained from ultra wideband (UWB) (up to l GHz) detection systems. The comparison indicates that for relatively lossfree distributed systems, such as SF6 insulated bus, the UWB system is up to two orders of magnitude more sensitive. UWB detection also embodies additional advantages such as facilitating the location of discharge sites and the rejection of external electrical noise. For discharge detection in plastic-insulated cables, true UWB detection is not practical because of frequency-dependent attenuation effects, although certain gains in sensitivity can be achieved with a detector bandwidth of up to 10 MHz. View full abstract»

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  • Partial Discharge Evaluation of Polyethylene Cable-Material by Phase Angle and Pulse Shape Analysis

    Page(s): 151 - 155
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    This paper reports on the correlation of chemical and physical degradation as a result of discharge activity and partial discharge measurements, using only real quantities. The materials investigated are LDPE and peroxide crosslinked PE. An 8-channel test arrangement, controlled by a real-time microprocessor system, has been employed for time-critical evaluation and data organization. It was concluded that the lifetime of polymeric insulating materials depends on the type of internal partial discharges as well as on space charge and conductivity distribution. Two competing mechanisms make it difficult to evaluate discharge behavior near inception voltage: (1) Concentration of discharges to eroded surface areas causes an increase in deteriorating energy, and (2) Surface charges and electron trapping cause a decrease in the field strength. A scanning electron microscope was used to correlate electrical measurements to physical deterioration. View full abstract»

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  • Interaction of Corona with Dielectric Material Until Damage

    Page(s): 156 - 162
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    A study of polyethylene terephthalate (PET) and polypropylene (PP) treated by corona discharge for a short time is presented. Different techniques of analysis such as inverse chromatography, infrared spectroscopy, loss tangent and electric strength were used. Working at 50 Hz with a gap of 2 mm and different gases, the analysis of the polymer after treatment has shown that a limit in the transformation of the surface may be considered. Thus a critical time is defined between a pure transformation and a degradation. This latter phase is also studied with a cross linked polyethylene (XLPE). The infrared analysis and electric strength measurements have shown the role played by the relative humidity present in air. View full abstract»

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  • Chemical and Discharge Effects in Plasma Etching with Freons and Other Electronegative Gases

    Page(s): 163 - 167
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    Low pressure plasmas of halogens, halocarbons, and their mixtures are in general use for etching micron-sized features on Si, GaAs, and InP. Several processing parameters may be varied to optimize plasma conditions for etching rates and profile control. Manipulation of substrate temperature, pressure, applied frequency and gas feed composition are discussed in detail and specific examples are presented to illustrate these effects on etching Si and III-V compounds. View full abstract»

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  • Particle Charging in DC Corona Fields

    Page(s): 168 - 171
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    After a brief review of the currently accepted theory of particle charging in corona fields in air by both ionic bombardment and diffusion in the dark space surrounding the dc corona glow, the paper presents some of the recently published findings on particle charging within the corona glow. The study was made possible by the discovery that additions of CO2 to air in a 5 to 20% range will increase a cylindrical positive corona glow to a size which is sufficiently large to allow particles to be dropped on to various trajectories parallel to the corona wire and their charge to be measured. The influence of the shape of the particles when exposed to corona charging is also discussed. View full abstract»

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  • Charging of Insulator Surfaces by Ionization and Transport in Gases

    Page(s): 172 - 178
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    Insulator surfaces in gases collect charge when the rate of charge arrival exceeds the rate of conduction by the insulator from the surface region. The source of the collected charge may be in close proximity to, and hence greatly influenced by, the surface. Alternately, the source may be remote so that it releases charge independent of the surface accumulation. For the latter arrangement, charge transport through the gas greatly influences where it is collected. Surface charging is desired in some situations, such as for producing images or for processing. Charging is undesirable and hazardous in other situations; for example, where electrical failure may be triggered. A third possibility makes use of surface charge collection as a diagnostic procedure for materials and transport studies. This paper is concerned with the basic production and accumulation of surface charges from the adjacent gas and presents results on the processes involved. Transport parameters of drift, diffusion, and spacecharge effects are considered. Examples of charging and measured distribution under different conditions, including saturation effects, are analyzed. View full abstract»

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  • Pulse Corona Discgarge in Electrostatic Precipitators

    Page(s): 179 - 186
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    In electrostatic precipitators (ESPs) the electric field is responsible for producing ions in the vicinity of the corona wires, charging particles, and transporting charged particles to the collecting plate. In standard Cottrell-type precipitators, these functions are performed by applying a dc voltage between corona electrodes and collecting plates. Because ion production requires a high electric field strength near the cathode while particle transport is optimized in a uniform field, this arrangement is always a compromise, and sometimes a poor one. Energizing precipitators with both a dc base voltage and superimposed pulse voltage, on the other hand, provides for a separation of the functions; particle transport being performed by the dc base voltage and ion production by the pulse voltage. Besides offering improved control, pulsed energization provides for inherently better performance of ESPs, due in part to enhancement of particle charge as a result of ion density concentration and also to a more uniform corona current distribution along the length of the corona wire. This paper discusses these aspects of pulse charging as well as its effect on back corona, a phenomenon which degrades performance of ESPs for high resistivity dust conditions. Laboratory and full scale field tests of pulse energized ESPs are also described and analyzed. These tests show that the application of fast pulses to ESPs results in considerable improvement of collection efficiency. View full abstract»

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  • IEEE Electrical Insulation Society Multifactor Stress Committee

    Page(s): 187
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  • IEEE Electrical Insulation Society IEEE Transactions on Electrical Insulation

    Page(s): 188-a
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    Freely Available from IEEE
  • Information for authors

    Page(s): 188b
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Aims & Scope

This Transactions ceased production in 1993. The current retitled publication is  IEEE Transactions on Dielectrics and Electrical Insulation.

Full Aims & Scope