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IEEE Transactions on Electrical Insulation

Issue 3 • Date June 1991

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Displaying Results 1 - 25 of 25
  • Comments on "The temperature dependence of homogeneous field breakdown in synthetic air" by W.S. Zaengl et al

    Publication Year: 1991
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (104 KB)

    For original paper see ibid., vol.26, no.3, p.380-90 (1991). In the above-named paper the unit Townsend (Td) is used when referring to gaseous collision parameters. With reference to electrical insulation, it may be argued that, on grounds of its magnitude, the Townsend is an impractical unit.<> View full abstract»

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  • Discussion: partial discharges in ellipsoidal and spheroidal voids

    Publication Year: 1991, Page(s):537 - 539
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (214 KB)

    Some questions are raised regarding the model described by Crichton et al. (see ibid. vol.24, p.335-342, 1989) in which the entire volume of the void is considered to be involved in the discharge process. The commenter questions how it can be explained that an increase in the applied voltage results in an increase in the discharge magnitude. In response it is noted that the assumption was made to ... View full abstract»

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  • The temperature dependence of homogeneous field breakdown in synthetic air

    Publication Year: 1991, Page(s):380 - 390
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (820 KB)

    The time-resolved Townsend method is used to measure, among other parameters, the effective coefficient of ionization of α¯/N as a function of E/N in synthetic air (80% N2 , 20% O2 by volume) within a temperature range of ~27 to 124°C, where N is the gas number density, and E the electric field strength. Results show that eff... View full abstract»

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  • Modulation of partial discharge activity in GIS insulators by X-ray irradiation

    Publication Year: 1991, Page(s):460 - 468
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (704 KB)

    A system was assembled which can perform high-sensitivity partial discharge (PD) measurements under combined electric stress and X-ray irradiation on 138-kV class gas-insulated switchgear (GIS) post insulators. Under X-ray irradiation, the PD pulse repetition rate is increased and the discharge inception voltage (DIV) is sharply reduced. The DIV of these insulators under X-ray irradiation was reco... View full abstract»

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  • Charge accumulation on insulating spacers for HVDC GIS

    Publication Year: 1991, Page(s):418 - 427
    Cited by:  Papers (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (812 KB)

    A capacitive probe measurement that can be used to quantify the charge density on solid insulators is introduced. Studies performed in the development of a ±125 kV high-voltage DC (HVDC) gas-insulated converter station and ± 500 kV HVDC switchgear (HVDC-GIS) are reviewed. The properties and mechanisms of surface charging, the optimum design of the spacer and its breakdown characteris... View full abstract»

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  • Field behaviour at a triple junction in composite dielectric arrangements

    Publication Year: 1991, Page(s):500 - 509
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (548 KB)

    The author examines the field behaviour at and near various points of contact between a solid dielectric and a conductor. The topics discussed include analytical expressions and numerically calculated results of field strength as well as their potential practical applications. The effect of conductivity is explained in some cases. There are principally three contact conditions depending on the con... View full abstract»

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  • A continuous UHF monitor for gas-insulated substations

    Publication Year: 1991, Page(s):469 - 478
    Cited by:  Papers (54)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (664 KB)

    Assessing the condition of a GIS by measuring the UHF signals generated in it by partial discharges gives warning of developing faults. The signals are taken from couplers built into the equipment. The couplers are continuously monitored using special amplifying and detection units connected in a digital optical fiber network. The data collected can also be interpreted by an expert system and an a... View full abstract»

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  • On exponential growth [of gas breakdown]

    Publication Year: 1991, Page(s):378 - 379
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (96 KB)

    The agreement obtained between measured breakdown voltages and predicted breakdown values is frequently used as a means of assessing the validity of the theory/model in question. However, owing to the mathematical nature of exponential growth, it is easy to formulate a criterion that provides acceptable breakdown values, although the criterion may contain totally unrealistic features. An example f... View full abstract»

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  • Optimum electrical PD test method for large capacitors

    Publication Year: 1991, Page(s):479 - 486
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (596 KB)

    The optimum method for electrical partial discharge testing of large capacitors, including the effects of internal inductance, is determined. The results indicate that internal inductance does not adversely affect detection sensitivity if the detection impedance is made equal to the critical damping resistance. This has the advantage of providing a nonresonant waveform which can be detected in a n... View full abstract»

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  • Comparative analysis of methods for computing 2-D and 3-D electric fields

    Publication Year: 1991, Page(s):529 - 536
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (572 KB)

    On the basis of four high-voltage (HV) examples, electrical field calculations were performed using different computational methods. Three examples represent axisymmetric arrangements, one example is three-dimensional. The computations were performed using a boundary element program from the University of Sarajevo, a program based on the charge simulation method, developed at the Technical Univers... View full abstract»

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  • Surface charging and flashover of spacers in SF6 under impulse voltages

    Publication Year: 1991, Page(s):428 - 442
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (952 KB)

    The authors describe a series of experiments to study prebreakdown spacer charging and subsequent flashover in a compressed gas insulated rod-spacer-plane system under positive impulse voltages. Prebreakdown corona is identified as the most likely source for spacer charging. Surface charges were measured in situ with capacitive probes after the applied lightning impulse voltage had decayed to zero... View full abstract»

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  • Computer-aided impulse-voltage testing

    Publication Year: 1991, Page(s):344 - 348
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB)

    The automation of impulse voltage tests by a control and measuring system based on computers (computer-aided control and measurement system) offers new possibilities for high-voltage (HV) research and quality inspection. An industrially manufactured computer-aided control and measurement system is presented. Its hardware is characterized by a master computer for data input, operation, and data pro... View full abstract»

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  • Electric field theory and the fallacy of void capacitance

    Publication Year: 1991, Page(s):458 - 459
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (136 KB)

    The concept of the capacitance of a gaseous void is discussed as applied to electrical insulation science. The most pertinent aspect of the capacitance definition is that of reference to a single-valued potential difference between surfaces. This implies that these surfaces must be surfaces of equipotential. With this essential characteristics the validity of void capacitance is examined View full abstract»

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  • Surface current density K: an introduction

    Publication Year: 1991, Page(s):416 - 417
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (100 KB)

    The author discusses the vector surface of current density K used in electrical insulation studies. K is related to the vector tangential electric field Kt at the surface of a body by the vector equation KE t where Γ represents the surface conductivity. The author derives a surface continuity equation that represents... View full abstract»

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  • A question in electromagnetic theory

    Publication Year: 1991, Page(s):510 - 512
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    Electromagnetic theory formulations may be stated with or without surfaces of discontinuity. The latter approach is simpler in many respects, but it presents some difficulties if the realization of no time dependence is to be considered. This dilemma arises in electrical insulation studies in which interfaces between media are present. The author examines two mathematically simple cases in order t... View full abstract»

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  • Illusory Paschen curves associated with strongly electronegative gases

    Publication Year: 1991, Page(s):391 - 397
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    Using analytical linear regression analysis, it is shown that, for a strongly electronegative gas, the (direct) breakdown voltage curve obtained with a moderately nonuniform field is effectively linear. For a strongly electronegative gas, breakdown voltage measurements made on a moderately nonuniform field test gap give rise to an apparently liner curve. The curve can be designated a Paschen curve... View full abstract»

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  • The theory and measurement of partial discharge transients

    Publication Year: 1991, Page(s):487 - 497
    Cited by:  Papers (28)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (748 KB)

    A theoretical approach to partial discharge transients is presented. This approach is based on the relationship between the charge induced on the measurement electrode by those created in the interelectrode volume during partial discharge activity. The primary sources for these induced charges are the charges which, as a result of partial discharge activity, are distributed within the voids of the... View full abstract»

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  • On the assessment of extremely low breakdown probabilities by an inverse sampling procedure [gaseous insulation]

    Publication Year: 1991, Page(s):367 - 377
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (628 KB)

    First breakdown voltages obtained under the inverse sampling procedure assuming a double exponential flashover probability function are discussed. An inverse sampling procedure commences the voltage application at a very low level, followed by applications at stepwise increased levels until a breakdown occurs. Following a breakdown, the procedure is restarted at the initial level. The procedure is... View full abstract»

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  • Analysis of the temporal electric fields in lossy dielectric media

    Publication Year: 1991, Page(s):513 - 528
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (936 KB)

    The time-dependent electric fields associated with lossy dielectric media are examined. The analysis illustrates that, with respect to the basic time constant, these lossy media can take a considerable time to attain a steady-state condition. Time-dependent field enhancement factors are considered, and inherent surface-charge densities quantified. The calculation of electrostatic forces on a free,... View full abstract»

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  • Influence of a dielectric barrier on the stochastic behaviour of Trichel-pulse corona

    Publication Year: 1991, Page(s):405 - 415
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (704 KB)

    The influence of a solid polytetrafluorethylene (PTFE) dielectric barrier on the stochastic behaviour of negative (Trichel) pulse corona discharges in air is examined. This behavior is revealed from measurement of conditional and unconditional corona pulse-amplitude and pulse-time--separation distributions. The results indicate that the presence of a dielectric surface on the anode effectively red... View full abstract»

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  • SF6 insulation and its application to HV equipment

    Publication Year: 1991, Page(s):358 - 366
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (748 KB)

    Very fast transient overvoltage (VFTO) problems and studies on SF 6 insulation are outlined, and trends in gas-insulated equipment design are discussed. The discussion covers recent topics on development and typical products, including 550 to 800 kV gas-insulated switchgears (GISs) and 275 kV gas-insulated transformers. The authors deal with insulation in nonuniform electric fields View full abstract»

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  • Study of power coil resonance phenomena based on traveling wave theory

    Publication Year: 1991, Page(s):349 - 357
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (732 KB)

    New measurement capabilities allow greater in-depth investigations of the propagation of guided electromagnetic waves inside a coil. Based on numerous measurements of the frequency-dependent conductance and susceptance of various arrangements of cylindrical and disc-type single-layer air-core coils, resonance phenomena of such arrangements, and the main influencing factors, are investigated. The r... View full abstract»

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  • Effect of surface charge on impulse flashover of insulators in SF 6

    Publication Year: 1991, Page(s):443 - 452
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    The effect of surface charge on the impulse flashover of short spacers in SF6 was investigated. A split-electrode arrangement allowed scanning of the entire space surface by a capacitive probe. With a heterocharge distribution which facilitates both inception and propagation of the discharge, the flashover level is reduced by as much as 50% for sinusoidally distributed charge of peak de... View full abstract»

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  • Theory of positive onset corona pulses in SF6

    Publication Year: 1991, Page(s):398 - 404
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    The mechanism of formation of positive corona onset pulses in SF 6 at 100 kPa is examined. A constant positive voltage of 50 kV is applied to an 0.5-cm diameter sphere located 6.5 cm from a grounded plane. The calculated current pulse has a width at half maximum amplitude of ~0.3 ns, thus explaining the origin of subnanosecond current pulses in SF6. During the current pulse a... View full abstract»

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  • PD phenomena on dielectric surfaces under DC stresses influenced by air humidity

    Publication Year: 1991, Page(s):453 - 457
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    Based on fundamental investigations of the charge accumulation on the surface of dielectric materials relevant for DC test equipment, it was found that partial discharge (PD) phenomena under DC stresses are affected by both local and remote charge generation. With increasing air humidity both charge generation processes are intensified, resulting in an unexpectedly strong reduction of the PD incep... View full abstract»

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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