Surface Flashover of Fiberglass Reinforced Epoxy Composite Insulation in Vacuum at Liquid Nitrogen and Room Temperatures using Power Frequency AC and Lightning Impulse Waveforms

  • I. Sauers
  • D. R. James
  • H. Rodrigo
  • M. O. Pace
  • B. W. McConnell
  • V. P. Patania
  • A. R. Ellis
Chapter

Abstract

The dielectric strength of vacuum insulation is reduced considerably when high voltage electrodes are bridged by solid insulation. Further reduction of strength can occur when the solid material outgases as in the case of fiber reinforced plastics (FRP). Even when the overall vacuum is acceptable, the higher gas pressures near the insulator surface can result in unacceptably low hold- off strengths. For superconductor applications in high voltage power equipment the problem of outgassing may be reduced or eliminated by the low temperatures employed. We will report on ac and impulse surface flashover studies of two types of fiberglass reinforced epoxy composite insulators, G-10 and G-11, at ambient temperature and at low temperature, using liquid nitrogen cooled electrodes, at vacuum pressures below l.0x10−6 Torr (1.3x10−4Pa). Also, AC and impulse breakdown voltages for a pure vacuum gap are compared to the gap breakdown voltages obtained for the electrode-insulator-electrode arrangement. In addition, preliminary results on the effect of orientation of the layers in G-10 and G-11 on breakdown, surface flashover, and puncture are also presented.

Keywords

Quartz Polyethylene Epoxy Polystyrene Nylon 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    H. Fengnian and W. Weihan, Electrical breakdown of vacuum insulation at cryogenic temperature, IEEE Trans, on Elect. Insul, 25(3):557 (1990).CrossRefGoogle Scholar
  2. 2.
    J. Gerhold, Properties of cryogenic insulants, Cryogenics, 38(11): 1063 (1998).CrossRefGoogle Scholar
  3. 3.
    M. Kosaki, M. Nagao, N. Shimizu and Y. Mizuno, Solid insulation and its deterioration, Cryogenics, 38(11):1095 (1998).CrossRefGoogle Scholar
  4. 4.
    C.H. Park, M. Hara, and M. Akazaki, Effects of mechanical stresses on the dielectric breakdown strengths of PET and FRP, IEEE Trans, on Electr. Insult., EI-17(3): 234 (1982).CrossRefGoogle Scholar
  5. 5.
    C.H. Park, M. Hara, and M. Akazaki, Effects of temperature and voltage on dielectric breakdown strengths of PET and FRP under mechanical stresses, IEEE Trans, on Electr. Insul., EI-17(6):546 (1982).CrossRefGoogle Scholar
  6. 6.
    G. Lupo, C. Petrarca, L. Egiziano, G. Spagnuolo, and V. Tucci, A methodological approach for improvement of vacuum-insulated hv bushings, Proc. XVII Int. Symp. On Discharges And Elect. Insul. In Vacuum, (1996).Google Scholar
  7. 7.
    H. Craig Miller, High voltage performance characteristics of solid insulators in vacuum, in: “High Voltage Vacuum Insulation,” R. V. Latham, ed., Academic Press, London, (1995), p299.Google Scholar
  8. 8.
    J.M. Wetzer, HV design of vacuum components, IEEE Trans, on Diel, and Elect. Insul., 2(2):202 (1995).CrossRefGoogle Scholar
  9. 9.
    J.M. Wetzer, Vacuum insulator flashover, Proc. of the XVII Int. Symp. on Discharges and Electrical Insulation in Vacuum, 449, Berkeley (1996).Google Scholar
  10. 10.
    R.V. Latham, The operational characteristics of practical HV gaps, in: “High Voltage Vacuum Insulation, Basic Concepts and Technological Practice,” R. V. Latham, ed., Academic Press Limited, London, (1995), p. 48.Google Scholar
  11. 11.
    C. H. de Tourreil, Surface flashover voltage of spacers in vacuum at cryogenic temperatures, in: “Advances in Cryogenic Engineering,” 22:306 (1977).Google Scholar
  12. 12.
    B. Mazurek, High voltage vacuum insulation at cryogenic temperatures, in: “High Voltage Vacuum Insulation,” R. V. Latham, ed., Academic Press Limited, London (1995), p. 487.CrossRefGoogle Scholar
  13. 13.
    A. Neuber, H. Krompholz, L. L. Hatfield, Dielectric surface flashover in vacuum at cryogenic temperature (100 K), IEEE Annual Report — Conference on Electrical Insulation and Dielectric Phenomena, 575 (1997).Google Scholar
  14. 14.
    R. Hawley, Solid insulators in vacuum: A review, Vacuum, 18(7):383, (1968).CrossRefGoogle Scholar
  15. 15.
    C.A. Ramm, International Conference on Instrumentation for High Energy Physics, Berkeley, (1960).Google Scholar
  16. 16.
    A.S. Pillai and R. Hackam, Surface flashover of solid insulators in atmospheric air and in vacuum, J. Appl. Phy., 58(1):146 (1985).ADSCrossRefGoogle Scholar
  17. 17.
    P.H. Gleichauf, Electrical Breakdown over Insulators in High Vacuum, J. Appl. Phys., Vol. 22(6), 766–771 (1951).ADSCrossRefGoogle Scholar

Copyright information

© Kluwer Academic/Plenum Publishers, New York 2000

Authors and Affiliations

  • I. Sauers
    • 1
  • D. R. James
    • 1
  • H. Rodrigo
    • 1
  • M. O. Pace
    • 1
  • B. W. McConnell
    • 1
  • V. P. Patania
    • 1
  • A. R. Ellis
    • 1
  1. 1.Oak Ridge National LaboratoryOak RidgeUSA

Personalised recommendations