Resistance of pollution in equivalent electric circuit of flashover

Flazi, S.; Ouis, A.; Boukhennoufa, N.

doi:10.1049/iet-gtd:20050447

Cited by 5 publications

(6 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast with the behaviour obtained using a plane or cylindrical models, where the residual resistance is monotonic decreasing function [7,11], the estimated resistance is not necessarily decreasing and it seems to remain constant especially when the arc position is on the bottom surface. This means that in this specific insulator shape, the backward direction of arc propagation contributes, more effectively, to the increase of conduction paths [16].…”

Section: Modelling Of the Pollution Layermentioning

confidence: 91%

See 1 more Smart Citation

Prediction of DC flashover voltage of cap‐and‐pin polluted insulator

Abimouloud

Arif

Korichi

et al. 2019

IET Science, Measurement & Technology

View full text Add to dashboard Cite

Section: Modelling Of the Pollution Layermentioning

confidence: 91%

“…Indeed, cap-and-pin insulators cannot be simply replaced by cylindrical or rectangular shape [16]. To overcome this situation, a new expression for the residual resistance is proposed.…”

Section: New Proposed Model Based On Two Cylindrical Conductorsmentioning

confidence: 99%

Prediction of DC flashover voltage of cap‐and‐pin polluted insulator

Abimouloud

Arif

Korichi

et al. 2019

IET Science, Measurement & Technology

View full text Add to dashboard Cite

“…Flazi et al [54] commented on Hampton's criterion and Wilkins 9 criterion using multidirectional and circular-sector setups. They proposed that flashover is possible if the electric field distribution along the leakage distance is sufficient for discharge evolution by progressive breakdown between the discharge and the electrolyte.…”

Section: *2 Mechanisms Of Discharge Propagation Over An Electrolytementioning

confidence: 99%

Mechanisms of arc propagation over an ice surface /

Farokhi¹

2010

View full text Add to dashboard Cite

Outdoor insulation design with regard to pollution and icing performance is a critical factor for reliability of overhead transmission lines. The majority of failures occurring on transmission lines are caused by environmental conditions such as lightning, pollution and/or ice. Accumulated ice on insulators may initiate corona discharge; these partial arcs sometimes lead to flashover. This phenomenon is mainly caused by the presence of a highly conductive water film on the surface of the ice and ice-free zones, often called air gaps, along the insulators, and decreased insulator leakage distance caused by ice bridging.The general objective of this research is to investigate the physical mechanisms involved in the propagation of electric arc on the surface of ice. In the present research work, high-speed photography techniques was combined with synchronized electrical measurements to study the various parameters of arc on an ice surface, such as channel radius and propagation velocities. These results, together with studying the propagation patterns and arc foot geometries, provide background information for understanding the complete flashover phenomenon. Arc root structure, current profile, propagation pattern and velocity were investigated under positive and negative polarities. Water film conductivity and thickness, and relative air humidity were also analyzed as influencing parameters of arc propagation. The effects of different mechanisms, e.g. collision and thermal ionization, buoyancy force and electrostatic force, on different stages of arc propagation are also discussed.Repetitive patterns corresponding to arc decays were observed during arc propagation. During arc re-ignitions, an anode-directed streamer was found to be dominant, regardless of the polarity of applied voltage. The arc root under de-positive applied voltage was branched; on the contrary, the negative arc root appeared as a diffused luminous region. In the arc channel section, two distinct regions were distinguished. A linear relationship between the initiation current and the inverse of residual resistance was established, showing how important is the effect of water film thickness on the initiation of discharge. It was found there is a direct relationship between the slope of current increase and the applied water conductivity. Air humidity increases the voltage gradient along the arc channel and reduces the discharge activities at the arc tip. However, it could influence the arc formation and its propagation by changing the thickness of the water film. A change in the dominant mechanism from thermal ionization to collision ionization in the enhanced electric field was found to be responsible for the flashover. Tare. L'effet de différents mécanismes comme les collisions et l'ionisation thermique, la force de flottabilité et la force électrostatique sur les différentes étapes de la propagation de l'arc ont également été discutés. 11 RESUME

show abstract

“…Unfortunately, the proposed criteria and mechanisms are not yet confirmed, and the disagreement between the various hypotheses remains a subject for discussion [22, 23].…”

Section: Introductionmentioning

confidence: 99%

“…This parameter is the electric field distribution in the air near the electrolyte surface, between the discharge and the ground electrode [24]. Based on this conclusion, we proposed the following flashover criterion: ‘Flashover is possible if the electric field distribution along the leakage distance is sufficient for discharge elongation by a progressive breakdown between the discharge and the electrolyte’ [22].…”

Section: Introductionmentioning

confidence: 99%