Ion Migration in the Process of Water Freezing under Alternating Electric Field and Its Impact on Insulator Flashover

Jiang, Xingliang; Wang, Quanlin; Zhang, Zhijing; Hu, Jianlin; Hu, Qin; Zhu, Chi

doi:10.3390/en10010061

Cited by 8 publications

(8 citation statements)

References 28 publications

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“…As shown in the figure, with the increasing of rain intensity, the flashover voltage decreases less than 10%. According to the studies in [18,19], the influence of the water conductivity can be summarized as follows: firstly, a higher conductivity can enhance the local field at the head of the avalanche; secondly, the electrons at the head of the avalanche at the positive side of the drop are faster absorbed by the drop surface and are therefore less efficient in producing photons for secondary avalanches that could enhance the space charge of the aborted streamer.…”

Section: Effects Of Rain Intensitymentioning

confidence: 99%

AC Flashover Performance of 10 kV Rod-Plane Air-Gapped Arresters under Rain Conditions

Xie

et al. 2018

Energies

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According to operational experience of power systems, the outdoor insulation strength can be reduced due to the effect of rain. Till now, little work has been done to investigate the flashover performance of air gapped arresters under rain conditions. Therefore, in this paper, experiments were carried out and the AC flashover performance of 10 kV arresters with different air gap structures was studied. The experimental results show that, for the tested arresters, the flashover current mainly flows through the air gaps and zinc oxide varistors under rain conditions. It is also confirmed that the flashover voltages decrease with the increasing of rain intensity and conductivity. In the windward direction, the wind can distort the water streams between the air gaps and rise the flashover voltages. In the leeward direction, if the rod electrode is beyond the range of the plane electrode, the flashover voltage researches the smallest value when the wind speed is 4 m/s. Analysis and discussions have been done to explain the experimental results, and the research in this paper may provide reference to improve the flashover performance of air gapped arresters under rain conditions.

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Section: Effects Of Rain Intensitymentioning

confidence: 99%

AC Flashover Performance of 10 kV Rod-Plane Air-Gapped Arresters under Rain Conditions

Xie

et al. 2018

Energies

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“…m is the characteristic exponent, indicating the effect of ice thickness on the arc flashover gradient. Similarly, the relationship between the arc flashover gradient of the snow-covered insulators and snow thickness can also be expressed by Equation (5). The results in Table 6 are fitted by using Equation (5).…”

Section: Effect Of D On E Lmentioning

confidence: 99%

“…Similarly, the relationship between the arc flashover gradient of the snow-covered insulators and snow thickness can also be expressed by Equation (5). The results in Table 6 are fitted by using Equation (5). The values of A d , m and R 2 are shown in Table 7.…”

Section: Effect Of D On E Lmentioning

confidence: 99%

“…Affected by micro-topography and micrometeorology along transmission line corridors, especially in mountainous areas, the insulation strength of transmission lines significantly decreases due to snow or ice superimposed by contamination accumulating on insulator strings. At the beginning of 2008 and 2018, China suffered two large-scale freezing rain and snow disasters [2][3][4][5][6]. The continuous rain and snow led to the depth of snowfall breaking through the historical extremes in some areas, which caused a series of accidents, such as break line, tower collapse, line trip, insulator string flashover, and communication failure.…”

Section: Introductionmentioning

confidence: 99%

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Flashover Performance and Process of Suspension Insulator Strings Artificially Covered with Snow

Guo²,

Xian

et al. 2018

Energies

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Snow accumulates on the surface of insulator string, causing a decrease in its electrical performance, seriously threatening the reliable operation of the power grid. Most previous studies have focused on iced insulators; however, there is a lack of research on snow-covered insulators. In this paper, to reveal the influencing mechanism that snow has on the electrical characteristics of insulator string, based on an artificial snowing test in a chamber, the effects of equivalent salt deposit density, applied voltage type, and snow thickness on the flashover performance of snow-covered insulators are analyzed, and the flashover process is investigated. The results show that the relationship between the arc flashover gradient and the equivalent salt deposit density is a power function with a negative exponent, which is similar to that of polluted and ice-covered insulator strings. For the insulator strings with the same snow accretion, the direct current (DC) arc flashover gradient is lower than the alternating current (AC) arc flashover gradient. The relationship between arc flashover gradient and snow thickness is also a power function. The formation of a dry band during the flashover of snow-covered insulator string is similar to the flashover of the polluted insulator, and the arc propagation along the surface of the snow-covered insulator is similar to the flashover of the iced insulator.

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“…Most of the previous research has focused on the flashover properties of ice-covered insulators [13][14][15]. Few studies have reported the icing mechanism of insulators.…”

Section: Introductionmentioning

confidence: 99%

A Predictive Model for Dry-Growth Icing on Composite Insulators under Natural Conditions

et al. 2018

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Icing can adversely influence electric power system security. Two main issues are caused by icing: the overload of transmission lines, and the reduction in the insulation ability of the insulators. Most previous research has focused on the flashover characteristics of ice-covered insulators, but research on the icing process of the insulator is seriously lacking. Considering the effect of icing shape, the outer airflow field of an insulator was calculated and the local collision efficiencies of water droplets (β 1 ) were investigated according to the Lagrange algorithm. The simulation showed that the values of β 1 on the insulator edge and rod are much higher than on the insulator surface, and both were significantly influenced by the wind speed and median volume diameter (MVD) of the water droplets. Based on thermal balance equations, a dynamic dry-growth icing model was established. Using the natural icing conditions of Xuefeng Mountain (China) as an example, validation experiments were conducted on a composite insulator and the climate parameters measured by multi-cylinders were used to model the icing shape and mass. The results indicate that high wind speed and low temperature increase icing rate; the icing was mainly concentrated on the windward side and the greatest horizontal thickness was generally on the insulator edge. The dry-growth model had an average error lower than 25% for icing thickness and an average error lower than 20% for icing mass, which were affected by icing roughness.

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Ion Migration in the Process of Water Freezing under Alternating Electric Field and Its Impact on Insulator Flashover

Cited by 8 publications

References 28 publications

AC Flashover Performance of 10 kV Rod-Plane Air-Gapped Arresters under Rain Conditions

AC Flashover Performance of 10 kV Rod-Plane Air-Gapped Arresters under Rain Conditions

Flashover Performance and Process of Suspension Insulator Strings Artificially Covered with Snow

A Predictive Model for Dry-Growth Icing on Composite Insulators under Natural Conditions

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