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Successful Detection of Insulation Degradation in Cables by Frequency Domain Reflectometry

  • Yoshimichi OhkiEmail author
  • Naoshi Hirai
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)

Abstract

We have succeeded in detecting the degradation of cable’s polymeric insulation well before its continual use becomes risky. Degradation of organic polymers is mainly caused by oxidation if the ambience around the cable contains oxygen. When organic polymers are oxidized, polar carbonyl groups are formed, by which the permittivity is increased. This in turn decreases the characteristic impedance of a polymer-insulated cable. If we inject electromagnetic waves in a very wide frequency range into the cable and measure the ratio of reflected power to injected power, the information on the effects of the characteristic impedance changes is included in the frequency spectra of the ratio. If we do inverse Fourier transform, we can convert the data to a time domain. Therefore, we can know the degraded portion by multiplying the velocity of electromagnetic waves in the cable.

Keywords

Insulation diagnosis Condition monitoring Aging Polymeric insulation Characteristic impedance Fault location Cable 

References

  1. 1.
    N. Hirai, T. Yamada, Y. Ohki, Comparison of broadband impedance spectroscopy and time domain reflectometry for locating cable degradation. Paper presented at the 2012 international conference on condition monitoring and diagnosis, Bali, 25 September 2012, B-3, pp. 229–232Google Scholar
  2. 2.
    T. Yamamoto, T. Minakawa, Final Report of the Project of ‘Assessment of Cable Aging for Nuclear Power Plants’ (Report JNES-SS-0903, 2009)Google Scholar
  3. 3.
    Institute of Electrical Engineers of Japan, Recommended Practice for Methods of Environmental Test and Flame Resistance Test for Electrical Wires and Cables for Nuclear Power Plants. Tech. Rep. (Division II) IEEJ 139, (1979) (In Japanese)Google Scholar
  4. 4.
    Y. Ohki, N. Hirai, T. Yamamoto, Need for condition monitoring and diagnosis of electric wires and cables used in nuclear power plants. Paper presented at the 2008 international conference on condition monitoring and diagnosis, Beijing, 23 April 2008, L2-08Google Scholar
  5. 5.
    Y. Ohki, N. Hirai, Localization of a damaged portion in electric cable by broadband impedance spectroscopy and FFT analysis. Paper presented at the 2010 annual conference of fundamentals and materials society, IEE Japan, Okinawa, 13 September 2010, 390 (In Japanese)Google Scholar
  6. 6.
    Y. Ohki, N. Hirai, Broadband impedance spectroscopy as a tool to evaluate the integrity of cable insulation. Paper presented at the 2010 international conference on condition monitoring and diagnosis, Tokyo, 8 September 2010, B3-5, pp. 313–316Google Scholar
  7. 7.
    Y. Ohki, T. Yamada, N. Hirai, Precise location of the excessive temperature points in polymer insulated cables. IEEE Trans. Dielectr. Electr. Insul. 20(6), 2099–2106 (2013)CrossRefGoogle Scholar
  8. 8.
    T. Yamada, N. Hirai, Y. Ohki, Sensitivity of broadband impedance spectroscopy as a location method of cable degradation. Paper presented at the joint technical meeting on dielectrics and electrical insulation and electric wire and power cable, IEE Japan, Tokyo, 22 February 2012, DEI-12-055/EWC-12-003 (In Japanese)Google Scholar
  9. 9.
    T. Yamada, N. Hirai, Y. Ohki, Effect of terminating impedance on the fault location in a cable by frequency domain reflectometry. Paper presented at the 2013 annual meeting, IEE Japan, Nagoya, 22 March 2013, 212 (In Japanese)Google Scholar
  10. 10.
    Y. Ohki, N. Hirai, Condition monitoring for predictive maintenance of cables insulated with FR-EPDM by frequency domain reflectometry. Paper presented at the 2014 international conference on condition monitoring and diagnosis, Jeju, 22 September 2014, OD1-1, pp. 57–60Google Scholar
  11. 11.
    T. Yamada, N. Hirai, Y. Ohki, Improvement in sensitivity of broadband impedance spectroscopy for locating degradation in cable insulation by ascending the measurement frequency. Paper presented at the 2012 international conference on condition monitoring and diagnosis, Bali, 24 September 2012, B-4, pp. 677–680Google Scholar
  12. 12.
    Atomic Energy Society of Japan, Code on implementation and review of nuclear power plant ageing management programs: 2008, (AESJ-SC-P005E, July 2012)Google Scholar
  13. 13.
    IAEA, Safety Reports Series No. 82, Ageing Management for Nuclear Power Plants: International Generic Ageing Lessons Learned, (IGALL, 2015)Google Scholar
  14. 14.
    Y. Ohki, N. Hirai, Effects of the structure and insulation material of a cable on the ability of a location method by FDR. IEEE Trans. Dielectr. Electr. Insul. 23(1), 77–84 (2016)CrossRefGoogle Scholar
  15. 15.
    N. Hirai, Y. Ohki, Abnormality detection over the whole cable length by frequency domain reflectometry. Paper presented at the 2017 annual meeting, IEE Japan, Toyama, 17 March 2017, 264 (In Japanese)Google Scholar

Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  1. 1.Department of Electrical Engineering and BioscienceWaseda UniversityTokyoJapan
  2. 2.Research Institute for Materials Science and TechnologyWaseda UniversityTokyoJapan
  3. 3.Joint Major in Nuclear EnergyWaseda UniversityTokyoJapan

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