Modeling of the AC Arc Discharge on Snow-covered Insulators

Univ. du Quebec a Chicoutimi, Quebec City
IEEE Transactions on Dielectrics and Electrical Insulation (Impact Factor: 1.28). 01/2008; 14(6):1390 - 1400. DOI: 10.1109/TDEI.2007.4401221
Source: IEEE Xplore


A mathematical model for predicting the ac flashover voltage of snow-covered insulators is presented. The arc constant parameters in air gaps and inside snow, as well as the arc reignition condition are determined using a cylindrical model. The effects of the arc length on the arc constants parameters are also investigated. The model is then applied to an EPDM insulator artificially covered with natural snow. There is good concordance between the flashover results determined from the mathematical model and those obtained experimentally.

13 Reads
  • Source
    • "The phenomena recorded during the disaster had not been encountered before and were quite different from the ones seen on the so-called snow-covered or snow-capped insulators [3] [4] [5] [6] [7] [8] [9]. "
    K Yaji · H Homma ·
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents the AC flashover process of a snow-bridged long-rod insulator used for 33 kV overhead lines in the presence of a salt contaminated snowstorm in a climatic chamber. The severity of the snowstorm was defined as having snow conductivity up to approximately 1,000 micro S/cm, 10 m/s of wind velocity, and 9.2 g/m3 of mass density of drifting snow. Leakage current waveforms under constant voltage stress were monitored. Visual observations of discharge propagation were also carried out by using a high-speed camera simultaneously with the leakage current measurement. The results showed that a spark-like partial discharge appeared at the snow gaps during the initial cycle of sequent current waves before flashover. Then the spark-like discharge bridged a gap between the insulator sheds and transferred to partial arc discharges. After the transition, partial arc discharges expanded and contracted along with the instantaneous electrical stress. When these were seen in the same phase angle as the power frequency, the partial arc discharges gradually propagated over the surface of the snow on the specimen until they were combined between both sides of the electrodes to reach flashover. The flashover processes were mostly same, even for various snow conditions. This process was always initiated at the snow gaps. Therefore, it was suggested that the appearances of snow gaps played an important role in the flashover process of a snow-bridged long-rod insulator.
    19th International Symposium on High Voltage Engineering – ISH 2015, Pilsen, Czech Republic; 08/2015
  • Source
    • "For ac arc models for ice-or snow-covered insulators [6] [9] [10] [11] the reignition criterion of the residual arc following a current zero of the critical leakage current for polluted insulators introduced by Rizk [13] [14] [15] is also used. However, it should be noticed that both Obenaus's method and Rizk's criterion cannot explain the arc root movement where these principles are necessary but not sufficient for predicting the flashover voltage. "

    19th International Symposium on High Voltage Engineering, Pilsen, Czech Republic; 08/2015
  • Source
    • "Flashover voltage characteristics of snow-covered insulators [4] [5] [6] [7] [8] [9] [10] [11] and the flashover model [10] [11] [12] [13] [14] [15] [16] [17] have been researched. Properties of wet and contaminated snow flashovers or discharges, such as the ones seen in Niigata, have not been hitherto investigated. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents the flashover characteristics of snow-bridged insulators, and the related discharge propagation phenomena in the presence of salt contaminated snowstorms. Two types of flashover tests, a) Snow accretion without voltage application, then apply the voltage after snow accretion, b) Snow accretion during voltage application, were carried out on a 33 kV long rod insulator with the snow conductivity controlled between 180 and 980 μS/cm. Method a simulates the "cold switch-on" situations. In this case, the flashover voltage is found to be inversely proportional to the fifth root of the snow conductivity. Further, the flashover voltage showed a relation to the leakage resistance of snow-bridged insulators. Method b simulates energized situations during a snowstorm. The concept of Method b is equivalent to the ???Ice Progressive Stress (IPS)??? method described in the IEEE Std. 1783-2009. In this case, partial arc discharges gradually increase owing to the development of snow accretion. Flashovers are mostly induced during the period of snowstorm suspension, because the arc discharge can develop into a flashover without the cooling effect of the blizzard. Melting snow by heating of electric power does affect flashover characteristics. The minimum flashover stress by Method b is lower than that by Method a. However, in particular case of Method b with higher snow conductivity, too much discharge activities prevent snow accretion on the insulator. This leads to snow melting or snow shedding.
    IEEE Transactions on Dielectrics and Electrical Insulation 12/2014; 21(6):2559-2567. DOI:10.1109/TDEI.2014.004565 · 1.28 Impact Factor
Show more