Compressed-Gas Insulation in Large Coaxial Systems

Doepken, H. C.

doi:10.1109/tpas.1969.292456

Cited by 36 publications

(10 citation statements)

References 4 publications

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“…1>2 > 14> 15 The layer reduces the field at the cathode surface and hinders any fieldemitted electrons from entering the gas, and oxide and tarnish layers on the cathode are shielded from any positive ions or charged particles. From the present investigation, in contrast to other work, 14 ' 15 it appears that the gas-breakdown values are influenced by the resistivity p of the insulating layer, probably because this controls the charging of dust particles on the layer and their ability to act as electronemission sites. The Vycoat and Neoprene layers on the negative inner electrode, with p > 10 13 £2m, gave the lowest breakdown fields; the polystyrene varnish, silicon grease and polyolefin layers, with p 5 lO l6 Q.m, gave the highest fields.…”

Section: Uniform-field and Negative Coaxial Breakdown 411 Breakdowncontrasting

confidence: 97%

“…This is not true for the present results in SF 6 and nitrogen (see Section 3.2.6). There is some similar evidence in the literature, but, whereas a few investigators found the positive value to be lower or did not observe any polarity effect under some conditions, 2 ' 6 others reported that the negative breakdown voltage was always lower than the positive, 2 ' 15> 23> 24 and Doepken 14 reported that the polarity effect depended on the pressure.…”

Section: Positive Coaxial Breakdownmentioning

confidence: 74%

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Impulse breakdown of compressed gases between dielectric-covered electrodes

MacAlpine¹,

Cookson

1970

Proc. Inst. Electr. Eng. UK

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The impulse breakdown of sulphur hexafluoride and nitrogen gas has been investigated at pressures up to 1 -5MN/m 2 and 5MN/m 2 (15 and 50atm), respectively, for voltages up to 700kV, in order to determine the effect of covering the electrodes with insulating film, under both uniform-and coaxial-field conditions. The first breakdown fields are given, as well as the conditioned values, as these are of practical importance. In general, insulated coverings markedly increased the breakdown field; with uniform-field conditions, they enabled Paschen's law to be obeyed for fields up to 130MV/m in sulphur hexafluoride, and 40MV/m in nitrogen, about 50% higher than the fields for which it is normally valid with uncovered electrodes at these pressures. Dust particles were shown to have a deleterious effect, particularly at the higher pressures and fields, and could lower the breakdown field by 30%. Polarity effects on breakdown were found for both gases, with covered and uncovered electrodes.

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Section: Uniform-field and Negative Coaxial Breakdown 411 Breakdowncontrasting

confidence: 97%

Section: Positive Coaxial Breakdownmentioning

confidence: 74%

Impulse breakdown of compressed gases between dielectric-covered electrodes

MacAlpine¹,

Cookson

1970

Proc. Inst. Electr. Eng. UK

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“…(c) Electrode coatings: Controlled insulating coatings on the electrodes, particularly the cathode, can significantly increase V s by 25% to 50% so that Paschen's law can be satisfied to higher pressure and fields than for bare electrodes [1,12,13].…”

Section: Electrode Effectsmentioning

confidence: 99%

“…Under DC conditions [13,17] the particles can cross the gap as soon as they are elevated. They can hover near the cathode and form 'fireflies'.…”

Section: Particle Contamination Effectsmentioning

confidence: 99%

Review of high-voltage gas breakdown and insulators in compressed gas

Cookson

1981

IEE Proc. A Phys. Sci. Meas. Instrum. Manage. Educ. Rev. UK

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In the past ten years there have been significant advances in the theoretical and experimental analysis of high-voltage gas breakdown and surface flashover of insulators in compressed gases. This has probably been fostered by the recent growth in the design and application of gas-insulated high-voltage equipment. The review describes the characteristics of compressed-gas breakdown, including the effects of failure of Paschen's law; conditioning; electrode area; material and surface; breakdown-voltage distribution; particle contamination; voltage waveform; temperature; and gas mixtures. The insulator-flashover characteristics are then described, including the effects of insulator-electrode interface; insulator material; insulator shape; voltage waveform; charge generation; particle contamination; surface contamination; conditioning; flashover distribution; and dependence on type of gas. The various mechanisms proposed for gas breakdown and insulator flashover are reviewed and discussed in relation to the experimental characteristics. Future theoretical and experimental work is suggested to clarify the gas-breakdown and insulator-flashover mechanisms, and which would also help bring about the design of improved high-voltage gas-insulated systems.

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“…[36,50,94,95] were made on coaxial geometries with various inner and outer conductor diameters. electrodes as a function of gas pressure [34,96].…”

mentioning

confidence: 99%