Selection of Station Insulators With Respect to Ice and Snow—Part I: Technical Context and Environmental Exposure

Farzaneh, M.; Baker, T.; Bernstorf, A.; Burnham, J.T.; Carreira, Tony; Cherney, E.A.; Chisholm, William A.; Christman, R.; Cole, Richard; Cortinas, John V.; Tourreil, C. de; Drapeau, J.F.; Farzaneh-Dehkordi, J.; Fikke, Svein M.; Gorur, R.S.; Grisham, T.; Gutman, Iván; Kuffel, J.; Phillips, Andrew J. K.; Powell, G.; Rolfseng, L.; Roy, M.; Rożek, T.; Ruff, D.L.; Schwalm, A. E.; Sklenička, V.; Stewart, G. A.; Sundararajan, R.; Szeto, M.; Tay, Roland Yingjie; Zhang, J.

doi:10.1109/tpwrd.2004.839731

Cited by 64 publications

(35 citation statements)

References 28 publications

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“…The ISP (g/cmXfiS/cm) is the product of the ice layer weight (g/cm of dry-arc distance) and the conductivity of the melted ice layer ((j,S/cm) [24]. The weight of accreted ice per centimeter of dry arc distance (g/cm) was assumed to be four times the ice thickness (mm) on the reference cylinder [21]. Considering an ice thickness of 15 mm, an ice layer weight of 60 g/cm can be considered for the present work.…”

Section: Flashover Results Presentation Using Icing Stress Product (Isp)mentioning

confidence: 99%

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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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Section: Flashover Results Presentation Using Icing Stress Product (Isp)mentioning

confidence: 99%

“…However, it is well established that several ice parameters, including type, density, amount and distribution, as well as the conductivity of applied water, may also have a significant influence on flashover voltage [20], [21].…”

Section: Equipment (Cigele) and Canada Research Chair On Engineering mentioning

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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“…The model for flashover on snow-covered insulator surfaces is still a challenge in the study of outdoor insulation. This situation arises from the complexity of the phenomena depending on a great number of parameters including temperature, contamination, volume conductivity, density, liquid water content, and conductivity of water melted from snow [2,67,70,71].…”

Section: -2 Developed Model To Estimate Arc Progress Inside Wet Snowmentioning

confidence: 99%

“…However, it is well established that several parameters, including snow type, density, amount and distribution, as well as melted-water conductivity are of major importance in affecting the withstand voltage characteristics of snow-covered insulators [2,7]. It has also been established that flashover performance of snow-covered insulators is affected by the height of snow and the ratio of snow-covered length over the total length of insulator [2,7,70]. …”

Section: -2 Developed Model To Estimate Arc Progress Inside Wet Snowmentioning

confidence: 99%

Modeling of AC arc inside wet snow =

Hemmatjou¹

2006

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“…These studies mainly include field observations [18], laboratory investigations of the ice accretion process and prediction of critical flashover voltage on ice-covered insulators [19,20,21,22,23,24]. [32,33].…”

Section: Introductionmentioning

confidence: 99%

Static modelling of AC flashover on contaminated insulators covered with ice using intelligent identificat ion methods =

Sabri¹

2009

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Selection of Station Insulators With Respect to Ice and Snow—Part I: Technical Context and Environmental Exposure

Cited by 64 publications

References 28 publications

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

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

Modeling of AC arc inside wet snow =

Static modelling of AC flashover on contaminated insulators covered with ice using intelligent identificat ion methods =

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