Insulation Effects of Hydrogen Gas for Cooling Turbine-Driven Generators

Mitsui, H.; Koyanagi, Eiji; Kenjo, S.; Yamauchi, Takeshi; Tari, M.

doi:10.1109/tei.1983.298640

Cited by 4 publications

(2 citation statements)

References 2 publications

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“…Also there exists a lot of published work (Ref. [2], [3], [5] etc.) concerning the breakdown of metallic electrode configurations with different field distributions.…”

Section: Introductionmentioning

confidence: 99%

Investigation regarding corona free endwinding design of form wound high voltage stator windings

Lerchbacher

Imamovic

Lemesch

et al. 2010

2010 Annual Report Conference on Electrical Insulation and Dielectic Phenomena

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High voltage rotating machines are supposed to be optimized not only in terms of performance but -among othersalso with respect to space and material utilization. When designing machines there has been considerable effort made to reduce the overall size of generators particularly in the axial direction. The winding is one of the more demanding parts of the generator but the end winding is an obvious place where axial space could be saved. For an optimized design, the distance between adjacent insulated bars or coils is a very important factor. Inadequate end winding spacing can lead to corona activity between adjacent coils or bars. Exact prediction of the needed space is difficult as prediction is dependent upon several contributing factors. Dielectric properties of the insulation material, location of the bracing system, imperfection of insulation surface as well as of the corona inception and extinction voltage in the air gap between insulated electrodes are important factors to understand for an optimized end winding design.In this paper the results of experimental investigations on air for various electrode configurations are presented. Metallic electrodes were covered with standard insulation material which is used in generators.The corona inception and extinction voltages as well as the partial discharge rate and the amplitude were measured for different electrode configurations. Additionally, the corona discharges were monitored with a special UV camera. The distance and the pressure of the air were varied in a wide range.The main purpose of this study was to optimize and simplify the spacing requirements of the end winding design. Therefore the corona inception and extinction voltage in the air gap between insulated electrodes as a function of distance and pressure was measured. Subsequent to that, the translation between the classical Paschen's Law for breakdown and the corona inception and extinction voltage in the air gap between insulated electrodes was investigated.

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“…Also there exists a lot of published work (Ref. [2], [3], [5] etc.) concerning the breakdown of metallic electrode configurations with different field distributions.…”

Section: Introductionmentioning

confidence: 99%

Investigation regarding corona free endwinding design of form wound high voltage stator windings

Lerchbacher

Imamovic

Lemesch

et al. 2010

2010 Annual Report Conference on Electrical Insulation and Dielectic Phenomena

View full text Add to dashboard Cite

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“…Other practical issues are, for example, elimination of the corona discharge formation in high voltage insulating systems [2] and damage on plants due to atmospheric corona discharges [3]. Several investigations have been done in order to analyze the physical processes that initiate electrical breakdown and discharge development for different parameters (overvoltage, cathode material and its surface quality, gass pressure, etc.).…”

Section: Introductionmentioning

confidence: 99%

Effect of terpene admixture on negative corona current pulses in air

et al. 2004

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We present an experimental study of negative corona pulses in short point-to-plane geometry measured with nanosecond time resolution in air and in air with admixture of terpene vapours at atmospheric pressure. The aim of this work is to explain observed differences in the discharge on trees and plants and standard negative corona burning on a metal cathode. To this goal we have compared the waveform of the first negative corona current pulses in pure air with those in air with admixture of terpene vapours. The observed difference has been explained by the growth of thin polymeric layer on the cathode surface, which changes the cathode surface properties and the discharge mechanism.PACS: 52.80.Hc

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