Étude de l'influence des caractéristiques des isolateurs sur leurs performances électriques dans des conditions de givrage /

Chaarani, Rabah

doi:10.1522/17657064

Cited by 8 publications

(18 citation statements)

References 11 publications

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“…<0 (2)(3) This criterion, however, does not explain the mechanism and speed by which the arc actually moves. Hesketh assumed that when the arc moves, it is not shunted anywhere by a wet contamination layer.…”

Section: ^mentioning

confidence: 98%

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Étude des conditions critiques de la propagation de l'arc sur les isolateurs recouverts de glace =

Aboutorabi¹

2003

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Section: ^mentioning

confidence: 98%

“…Like insulator length, the diameter of the insulator is a further parameter which may influence the shape of the ice layer, and so its consequent resistance [3]. Thus, it is likely to have an influence on arc maintenance conditions.…”

Section: Effects Of Insulator Diameter On Arc Maintenance Conditionsmentioning

confidence: 99%

Étude des conditions critiques de la propagation de l'arc sur les isolateurs recouverts de glace =

Aboutorabi¹

2003

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“…In addition, the study of the effect of number and position of air gaps on the flashover voltage of a single short string of five IEEE standard insulators, covered with ice, showed that in the 4 air-gap configurations tested, the critical flashover voltage is lowest in the case of two air gaps at the top and bottom of insulator string [94], [95], [96].…”

Section: Effect Of Air Gapsmentioning

confidence: 99%

Two-arc dynamic modeling of AC and DC flashovers of EHV post station insulators covered with ice based on laboratory experiments /

Ledari¹

2014

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Ice and snow accretion on insulators has been recognized as a significant risk factor in the reliability of overhead transmission lines and substations. Accumulated ice on insulators can initiate corona discharge along ice-free zones, often called air gaps. In the presence of a highly conductive water film on the surface of the ice, while applied voltage is sufficiently high, corona discharge activity may be initiated and developed into partial arcs. Under certain conditions, these partial arcs may result in complete flashover.The general objective of this research is to study the flashover phenomenon on icecovered extra-high-voltage (EHV) post insulators. Hence, a two-arc dynamic model based on the existing mathematical models was proposed to predict the parameters of AC and DC flashovers. The model considers the arc as time-dependent impedance constituted of a resistance in series with an inductance. The residual ice layer is defined in terms of an equivalent resistance, where the equivalent surface conductivity is calculated by taking into account the water film flowing along the ice surface. The present contribution proposes a novel approach to determine the equivalent surface conductivity, based on fluid mechanics and the Navier-Stokes equations, as well as on a series of experiments carried out to measure the water film flow rate and conductivity.Moreover, the mechanisms of discharge initiation and arc development on the surface of the ice accumulated on the insulators were studied. Special attention was paid to evaluate the effect of the volume conductivity of the ice surface on the arc propagation velocity for different freezing water conductivities, using high-speed video camera techniques.The proposed models were successfully validated in laboratory using station post insulators -typically used in Hydro-Quebec 735 kV substations -under AC and DC voltages. The maximum AC and DC withstand voltages were experimentally determined based on IEEE Std 1783. Furthermore, the influence of the number and position of air gaps on the flashover performance of ice-covered insulators was investigated experimentally. Experimental results revealed that the air gap configuration affects the maximum withstand voltage significantly. The main characteristics of flashover, including minimum flashover voltage and leakage current, derived from the proposed two-arc dynamic model, respond properly to the variation of major parameters, namely, insulator length and freezing water conductivity.Finally, in order to interpret the performance of insulators under different air gap positions, the voltage and electric field distributions along the ice-covered insulator were simulated numerically during the melting period, using the Finite Element Method (FEM). Simulations results confirm that increasing the number of air gaps improves the maximum withstand voltage and uniformity of voltage distribution of EHV post insulators. Based on the results, the use of booster sheds and grading rings to improve the insulating performance of...

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“…En conséquence, un isolateur avec un grand diamètre accumulera plus de glace qu'un isolateur de même longueur et de plus petit diamètre, ce qui donnera une résistance résiduelle plus faible [33], [59].…”

Section: C) Diamètre Des Jupes De L'isolateurunclassified

Étude temporelle et fréquentielle du courant de fuite des isolateurs de poste recouverts de glace en vue du développement d'un système de surveillance et de prédiction en temps réel du contournement électrique /

Meghnefi¹

2007

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Étude de l'influence des caractéristiques des isolateurs sur leurs performances électriques dans des conditions de givrage /

Cited by 8 publications

References 11 publications

Étude des conditions critiques de la propagation de l'arc sur les isolateurs recouverts de glace =

Étude des conditions critiques de la propagation de l'arc sur les isolateurs recouverts de glace =

Two-arc dynamic modeling of AC and DC flashovers of EHV post station insulators covered with ice based on laboratory experiments /

Étude temporelle et fréquentielle du courant de fuite des isolateurs de poste recouverts de glace en vue du développement d'un système de surveillance et de prédiction en temps réel du contournement électrique /

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