High voltage research (breakdown strengths of gaseous and liquid insulators). Semiannual report, April 1--September 30, 1977

Technical Report · Tue Nov 01 00:00:00 EST 1977

DOI:https://doi.org/10.2172/5413599· OSTI ID:5413599

Christophorou, L. G.; James, D. R.; Pai, R. Y.; Mathis, R. A.; Pace, M. O.; Bouldin, D. W.; Christodoulides, A. A.; Chan, C. C.

Direct current breakdown strength measurements on a large number of multicomponent gas mixtures at low (approximately less than 1 atm) and high (approximately less than 5 atm) pressures led to the discovery of many gas mixtures of electron-attaching gases and strongly electron-attaching gases with N/sub 2/ and C/sub 3/F/sub 8/ which are superior to SF/sub 6/. Of special significance are mixtures containing C/sub 4/F/sub 6/ (perfluoro-2-butyne). The breakdown strength of one such mixture (20 percent C/sub 4/F/sub 6/ to 80 percent SF/sub 6/) is approximately 30 percent higher than pure SF/sub 6/ under identical conditions, both at low (approximately 0.7 atm) and high (4.6 atm) pressures. Perfluorocyclohexene (C/sub 6/F/sub 10/) and C/sub 5/F/sub 8/ (perfluorocyclopentene) were found at low pressure (approximately 0.2 atm) to be, respectively, approximately 2.1 and 2.2 times better than SF/sub 6/ under comparable conditions; they both have a potential as additives in gas mixtures. The effect of the inelastic electron scattering properties of a gas via negative ion resonances in the low-energy range (1 to approximately 4 eV) on the breakdown strength has been demonstrated for H/sub 2/, N/sub 2/, and CO and binary mixtures of these with SF/sub 6/ and C/sub 4/F/sub 6/ (perfluoro-2-butyne). The construction of a new high pressure (to approximately 11 atm), variable temperature (-50/sup 0/C to + 150/sup 0/C) apparatus has been completed and a practical test facility utilizing cylindrical electrode geometries has been put into operation; the first results on the latter apparatus were on SF/sub 6/-N/sub 2/ and c-C/sub 4/F/sub 8/--N/sub 2/ mixtures. Studies of environmental effects of dielectric gases via their electron-impact-induced decompositions and analysis of their breakdown products have begun using mass spectrometry and gas chromatography; C/sub 4/F/sub 6/ (perfluoro-2-butyne) seems to be resistant to electron-impact-induced decomposition indicating long-term stability.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5413599
• Report Number(s): ORNL/TM-6113
• Country of Publication: United States
• Language: English

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24 POWER TRANSMISSION AND DISTRIBUTION
CARBON FLUORIDES
BREAKDOWN
CARBON MONOXIDE
GAS-INSULATED CABLES
RESEARCH PROGRAMS
HYDROGEN
NITROGEN
DIELECTRIC PROPERTIES
MIXTURES
POWER SYSTEMS
SULFUR FLUORIDES
CABLES
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CARBON OXIDES
CHALCOGENIDES
CONDUCTOR DEVICES
CRYOGENIC FLUIDS
DISPERSIONS
ELECTRIC CABLES
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELEMENTS
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FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SULFUR COMPOUNDS
200300* - Electric Power Engineering- Power Transmission & Distribution- (-1989)