access icon openaccess Partial discharge characteristics of an air gap defect in the epoxy resin of a saturable reactor under an exponential decay pulse voltage

This is an open access article published by the IET and CEPRI under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/)
Received 27/05/2019, Accepted 18/12/2019, Revised 09/12/2019, Published 23/01/2020

Saturable reactor insulation is currently stressed by an exponential decay pulse voltage under normal operating conditions. The partial discharge (PD) characteristics of epoxy resin under an exponential decay pulse voltage were studied here and were compared at 25 and 110°C. In addition, this study compares these PD characteristics with those under a sinusoidal voltage to better measure the insulation design margin of the saturable reactor under an exponential decay pulse voltage. Finally, this study explains the PD mechanism based on the three-capacitor circuit model and space charge accumulation. Compared with the sinusoidal voltage, a higher amplitude, a higher inception voltage and fewer PDs are obtained under the pulse voltage. The reason may be related to the accumulation of space charge. Due to the duality of the space charge effect, the promotion effect of space charge accumulation on the PD under the pulse voltage is dominant, and an increase in temperature will weaken the promotion effect. In contrast, the inhibitory effect of space charge accumulation on the PD under the sinusoidal voltage is dominant. The experimental results can provide a basis for the optimal design of saturable reactor insulation under an exponential decay pulse voltage.

Inspec keywords: space charge; partial discharges; air gaps; resins

Other keywords: three-capacitor circuit model; saturable reactor insulation; PD mechanism; temperature 25.0 degC; partial discharge; epoxy resin; temperature 110.0 degC; air gap defect; space charge accumulation

Subjects: Polymers and plastics (engineering materials science); Dielectric breakdown and space-charge effects; Dielectric breakdown and discharges

References

    1. 1)
      • 18. IEC Standard 60270: ‘High-voltage test techniques – Partial discharge measurements’, 2001.
    2. 2)
      • 12. Wang, P., Xu, H., Wang, J., et al: ‘Effect of repetitive impulsive voltage duty cycle on partial discharge features and insulation endurance of enameled wires for inverter-fed low voltage machines’, IEEE Trans. Dielectr. Electr. Insul., 2017, 24, (4), pp. 2123–2131.
    3. 3)
      • 9. Guastavino, F., Coletti, G., Torello, E.: ‘Twisted pairs specimens subjected to several waveform voltages in presence of partial discharges’. IEEE Report Conf. on Electrical Insulation and Dielectric Phenomena, Cancun, Quintana Roo, Mexico, 2002, pp. 450–453.
    4. 4)
      • 16. Casale, M., Schifani, R., Holboll, J.: ‘Partial discharge tests using CIGRE method II’, IEEE Trans. Dielectr. Electr. Insul., 2000, 7, (1), pp. 133–140.
    5. 5)
      • 15. Mi, Y., Deng, S., Gui, L., et al: ‘Simulation study on iron-core loss and temperature distribution of saturable reactor for ±1 100 kV UHVDC converter valves’, High Volt. Eng., 2018, 44, (10), pp. 3359–3367. (in Chinese).
    6. 6)
      • 11. Wang, P., Cavallini, A., Montanari, G.C., et al: ‘Effect of rise time on PD pulse features under repetitive square wave voltages’, IEEE Trans. Dielectr. Electr. Insul., 2013, 20, (1), pp. 245–254.
    7. 7)
      • 7. Lv, Z., Rowland, S.M., Chen, S., et al: ‘Evolution of partial discharges during early tree propagation in epoxy resin’, IEEE Trans. Dielectr. Electr. Insul., 2017, 24, (5), pp. 2995–3003.
    8. 8)
      • 8. Hayakawa, N., Okubo, H.: ‘Partial discharge characteristics of inverter-fed motor coil samples under ac and surge voltage conditions’, IEEE Electr. Insul. Mag., 2005, 21, (1), pp. 5–10.
    9. 9)
      • 25. Khare, P.K., Keller, J.M., Gaur, M.S., et al: ‘Electrical conductivity in iodine-doped ethyl cellulose’, Polym. Int., 2010, 35, (4), pp. 337–343.
    10. 10)
      • 24. Emtage, P.R., Dwyerf, J.J.: ‘Richardson–Schottky effect in insulators’, Phys. Rev. Lett., 1966, 16, (9), pp. 356–358.
    11. 11)
      • 1. Cao, J., Davidson, C., Moulson, S.: ‘Dynamic modelling of saturable reactor for HVDC applications’, IET Sci. Meas. Technol., 2007, 1, (3), pp. 138–144.
    12. 12)
      • 17. ASTM standard D149-09-2013: standard test method for dielectric breakdown voltage and dielectric strength of solid electrical insulating materials at commercial power frequencies[S]. ASTM International, 2013.
    13. 13)
      • 5. Forssén, C., Edin, H.: ‘Partial discharges in a cavity at variable applied frequency part 1: measurements’, IEEE Trans. Dielectr. Electr. Insul., 2008, 15, (6), pp. 1601–1609.
    14. 14)
      • 3. Cao, J., Ji, F., Liu, J., et al: ‘Valve saturable reactor iron losses of ultrahigh-voltage direct current converter’, IET Sci. Meas. Technol., 2016, 10, (2), pp. 77–83.
    15. 15)
      • 6. Bao, L., Li, J., Zhang, J., et al: ‘Influences of temperature on partial discharge behavior in oil-paper bounded gas cavity under pulsating DC voltage’, IEEE Trans. Dielectr. Electr. Insul., 2016, 23, (3), pp. 1482–1490.
    16. 16)
      • 21. Gouda, O.E., Elfarskoury, A.A., Elsinnary, A.R., et al: ‘Investigating the effect of cavity size within medium-voltage power cable on partial discharge behaviour’, IET Gener. Transm. Distrib., 2018, 12, (5), pp. 1190–1197.
    17. 17)
      • 13. Wang, X., Taylor, N., Edin, H.: ‘Enhanced distinction of surface and cavity discharges by trapezoid-based arbitrary voltage waveforms’, IEEE Trans. Dielectr. Electr. Insul., 2016, 23, (1), pp. 435–443.
    18. 18)
      • 2. Yan, R., Liu, H., Ben, T., et al: ‘Research on stress of magnetically controlled saturable reactor under practical working conditions’. Int. Conf. Electrical Machines and Systems, Sydney, NSW, Australia, 2017, pp. 1–5.
    19. 19)
      • 4. Cui, Y., Zhu, L., Ji, S., et al: ‘Partial discharge development in needle-plane configuration of oil-paper insulation under AC voltage’, IEEE Trans. Dielectr. Electr. Insul., 2017, 24, (4), pp. 2469–2476.
    20. 20)
      • 22. Deng, J., Wang, M., Zhou, Y., et al ‘Partial discharge characteristics of uniform gap in oil-impregnated paper insulation under switching impulse voltage’, IEEE Trans. Dielectr. Electr. Insul., 2016, 23, (6), pp. 3584–3592.
    21. 21)
      • 20. IEC Standard 61934: ‘Electrical insulating materials and systems – Electrical measurement of Partial discharge under short rise time and repetitive voltage impulses’, 2011.
    22. 22)
      • 23. Simmons, J.G.: ‘Poole–Frenkel effect and Schottky effect in metal-insulator-metal systems’, Phys. Rev., 1967, 155, (3), pp. 657–660.
    23. 23)
      • 19. Li, Q., Liu, W., Han, S., et al: ‘Analysis on partial discharge characteristics of epoxy resin insulation during high-frequency electrical-thermal aging’, High Volt. Eng., 2015, 41, (2), pp. 389–395. (in Chinese).
    24. 24)
      • 27. Illias, H.A., Tunio, M.A., Bakar, A.H.A., et al: ‘Partial discharge behaviours within a void-dielectric system under square waveform applied voltage stress’, IET Sci. Meas. Technol., 2014, 8, (2), pp. 81–88.
    25. 25)
      • 26. Liu, T., Li, Q., Huang, X., et al: ‘Frequency-induced inflection point phenomenon and formation mechanism of partial discharge with polyimide films’, Proc. Chin. Soc. Electr. Eng., 2017, 37, (9), pp. 306–315. (in Chinese).
    26. 26)
      • 10. Hwang, D.H., Park, D.Y., Kim, Y.J., et al: ‘A comparison with insulation system for PWM-inverter-fed induction motors’. IEEE Int. Conf. on Electrical Machines and Systems, Shenyang, China, 2001, pp. 72–75.
    27. 27)
      • 14. Ying, L., Xiaolong, C.: ‘Electrical tree initiation in XLPE cable insulation by application of DC and impulse voltage’, IEEE Trans. Dielectr. Electr. Insul., 2013, 20, (5), pp. 1691–1698.
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