Numerical Study of Droplet Impact Dynamics on the ACSR Cable for Studying Ice Adhesion and Accretion on Real Power Lines

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Ledong Deng ◽  
Hong Wang ◽  
Zhu Xun ◽  
Rong Chen ◽  
Yudong Ding ◽  
...  
Keyword(s):  
Surface Structure ◽  
High Speed ◽  
Numerical Study ◽  
Power Line ◽  
Droplet Impact ◽  
Power Lines ◽  
Impact Dynamics ◽  
Severe Problem ◽  
The Impact ◽  
Ice Adhesion

Abstract Ice adhesion and accretion on power lines is a severe problem that can pose a threat to the electric power transmission, and this icing phenomenon is significantly related to the impact dynamics of freezing rain droplets. In the current paper, this impacting process was studied by using computational fluid dynamics, and the model was verified by an experiment with a high-speed camera. The detailed droplet impacting processes on the surface of a very commonly used overhead power line (the ACSR-type cable) were analyzed. The effects of surface wettability (θ = 67–135 deg) and initial droplet impact velocity (We = 22–219) on the evolution of the liquid–solid contact area during the whole process and the volume of the residual liquid on the power line surface after impact were studied. Meanwhile, the influence of the surface structure of the ACSR power line on the droplet impact dynamics was analyzed. Results show that the capturing of impacting droplets can be enhanced by the grooved structures on a hydrophilic ACSR power line surface, while differently the expelling of impacting droplets can be enhanced by these grooved structures on a hydrophobic ACSR power line surface. By analyzing the possible influence of the surface structure of an ACSR power line on the phase transition of impacting droplets, these grooved structures could facilitate the formation of ice nucleation which can finally make the ice adhesion and accretion on an ACSR power line is more serious than that on a traditional smooth cylindrical power line.

scholarly journals The impact of power lines on phytocenoses of the regional reserve “Uporovsky”, Tyumen Region, Russia

2020 ◽  
Vol 164 ◽  
pp. 07030
Author(s):  
Elena Popova
Keyword(s):  
Nature Reserve ◽  
Power Transmission ◽  
Electrical Power ◽  
Power Line ◽  
Power Lines ◽  
Individual Species ◽  
Right Of Way ◽  
Synanthropization Index ◽  
The Right ◽  
The Impact

The article reflects the results of anthropogenic impact on phytocenoses of the territory of the Uporovsky regional nature reserve (Uporovsky district, Tyumen region, Russia). On the territory of the Uporovsky regional nature reserve (Uporovsky district, Tyumen region) there is a 110 kV electrical power transmission line (power line) which has the length of 8 kilometers and the right-of-way width of about 30 meters. This power line is undoubtedly the main source of anthropogenic electromagnetic radiation in this area. The degree of participation of individual species in the herbage was determined by taking into account their relative abundance. When exposed to the power lines in the right-of-way area, flora biodiversity decreases due to the loss of a number of species. The effect of electromagnetic fields causes transformation of the vegetation cover, synanthropization and the subsequent complete destruction of natural vegetation. To determine the degree of anthropogenic load on the studied phytocenoses, the synanthropization index is determined. In the synanthropic fraction of the flora, 30 species belonging to 12 families were identified. The synanthropization index of the studied phytocenoses ranges from 6.6% to 81.2%. The largest number of synanthropic species is observed in the anthropogenic area.

scholarly journals The impact of power line-related mortality on the Cape Vulture Gyps coprotheres in a part of its range, with an emphasis on electrocution

2011 ◽  
Vol 21 (3) ◽  
pp. 311-327 ◽  
Author(s):  
ANDRÉ F. BOSHOFF ◽  
JOHAN C. MINNIE ◽  
CRAIG J. TAMBLING ◽  
MICHAEL D. MICHAEL
Keyword(s):  
Mortality Rate ◽  
Power Line ◽  
Power Lines ◽  
National Database ◽  
Annual Growth Rate ◽  
Mortality Factors ◽  
Positive Growth ◽  
The Impact ◽  
Annual Mortality ◽  
Related Mortality

SummaryThe global population of the Cape Vulture Gyps coprotheres, a threatened southern African endemic, is known to be impacted by electrocutions and collisions on power line infrastructure, but to date this impact has not been estimated or quantified. Using data in a national database from the period prior to our study, conducted in the Eastern Cape Province of South Africa, we estimated a mean annual mortality rate from power line-related mortality of around 14 vultures per year. After applying an adjusted rate based on the results of a landowner survey, this estimate increased to around 80 vultures per year (i.e. a 5.7 fold increase). For a number of reasons, the estimated mean annual mortality rate is considered to under-represent the true situation, and must therefore be considered a minimum value. A simple model was constructed and run to investigate the potential impact of the mortality rate from electrocution on the study population. It distinguishes between vulture subpopulations in areas of high and low electrocution threat, and a migratory subpopulation that moves between these two areas. The model, simulated over 50 years and applying a constant theoretical maximum annual growth rate of 2%, indicates positive growth of the population in those areas where the electrocution threat from power lines is low, whereas the population in those areas where this threat is high is predicted to crash to extinction, from electrocution mortality alone, within a 20–35 year period. The regional population is predicted to show positive growth over the 50 year period. However, for a number of reasons that relate to the nature of certain parameters used in the model, the simulations must be considered to be conservative, at best. In addition, other unnatural mortality factors (notably inadvertent poisoning, drowning in high-walled farm reservoirs, harvesting for the traditional medicine trade, local food shortage), which are additive to power line-related mortality have not been taken into account. Management recommendations aimed at obtaining an improved estimate of the mean annual mortality rate from power lines, and at ameliorating the impact of electrocutions on the regional Cape Vulture population, are briefly mentioned. These address the former by documenting ways to improve the quantity and quality of the field data, and the latter by identifying areas where urgnt action needs to be taken to reduce or avoid the electrocution of vultures, by mitigating extant ‘unsafe’ power line infrastructure, and by ensuring that that only ‘safe’ infrastructure is used for new power lines.

Influence of Wave Shape on the Impact of Shallow-Water Waves on Vertical Walls

2006 ◽  
Author(s):  
Claudio Zanzi ◽  
Pablo Go´mez ◽  
Julia´n Palacios ◽  
Joaqui´n Lo´pez ◽  
Julio Herna´ndez
Keyword(s):  
Shallow Water ◽  
Level Set ◽  
Water Waves ◽  
High Speed ◽  
Numerical Study ◽  
Local Level ◽  
Wave Shape ◽  
Shallow Water Waves ◽  
Vertical Walls ◽  
The Impact

A numerical study of the impact of shallow-water waves on vertical walls is presented. The air-liquid flow was simulated using a code for incompressible viscous flow, based on a local level set algorithm and a second-order approximate projection method. The level set transport and reinitialization equations were solved in a narrow band around the interface using an adaptive refined grid. The wave is assumed to be generated by a plunger which is accelerated in an open channel containing water. An arbitrary Lagrangian-Eulerian method was used to take into account the relative movement between the plunger and the end wall of the channel. The evolution of the free surface was visualized using a laser light sheet and a high-speed camera, with a sampling frequency of 1000 Hz. Several simulations were carried out to investigate the influence of the shape of the wave approaching the wall on the relevant quantities associated with the impact. The wave shape just before the impact was changed varying the total length of the channel. The results are compared with experimental results and with results obtained by other authors.

Review of Channel Characterization for Power Line Communications

2010 ◽  
Vol 108-111 ◽  
pp. 771-776
Author(s):  
Nan Tian Huang ◽  
Xiao Sheng Liu ◽  
Dian Guo Xu
Keyword(s):  
High Speed ◽  
Low Voltage ◽  
Systems Design ◽  
Power Line ◽  
Digital Data ◽  
Power Lines ◽  
Suitable Model ◽  
Actual Measurement ◽  
Power Line Communications ◽  
Medium Voltage

The power line communication (PLC) channel has been a transmission medium that enables to transfer high-speed digital data through the classical electrical wires. Channel characteristics of power lines are very important for communications systems design. In order to get the suitable model for power line communications analysis and improve the PLC communication quality, researchers do lots of study about the PLC channel characterizations based on actual measurement and theoretical analysis. This paper reviews the conclusions of recent studies, summaries the characteristics of PLC channel for medium voltage power lines and low voltage power lines. The further research is also put forward.

Dynamique de la végétation d'emprises de lignes de transport d'énergie

1984 ◽  
Vol 62 (8) ◽  
pp. 1730-1738
Author(s):  
M. Darveau ◽  
P. Bellefleur
Keyword(s):  
Woody Species ◽  
Power Line ◽  
Power Lines ◽  
Underlying Structure ◽  
Dichlorophenoxyacetic Acid ◽  
Border Line ◽  
Control Power ◽  
Composition And Structure ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

We made a preliminary study of the impact of phytocides on plant dynamics in the corridors of Hydro-Québec power lines. Three hypotheses were tested: the first assumed that the phytocides changed vegetation composition and structure in the corridors; the second assumed that the corridor under the power line favored the development of an ecotone at its border with the forest; the third assumed that the method used for initial cutting of the corridors (bulldozer or chain saw) affected the forthcoming vegetation for over 15 years. Vegetation was sampled on one control power line and four power lines maintained with mixtures of picloram, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, and sodium trichloroacetate. Multidimensional statistical analysis was used to show the underlying structure of the raw data and to test the hypotheses. We found out that phytocides are very efficient on woody species to the advantage of herbs, mostly grass, which invaded the corridors and created rather stable artificial communities. No significant ecotone was found at the border line of the corridors and the forest. The influence of the method for initial cutting of the corridors, although severe the first few years, disappeared after about 10 years under the action of the phytocides.

scholarly journals A numerical study of projectile impact on thin aluminium plates

2009 ◽  
Vol 223 (11) ◽  
pp. 2519-2530 ◽  
Author(s):  
M Raguraman ◽  
A Deb ◽  
G Jagadeesh
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Numerical Study ◽  
Impact Testing ◽  
Good Prediction ◽  
Residual Velocity ◽  
Shell Elements ◽  
Simulation Based ◽  
Mesh Density ◽  
The Impact

This article deals with a simulation-based study of the impact of projectiles on thin aluminium plates using LS-DYNA by modelling plates with shell elements and projectiles with solid elements. In order to establish the required modelling criterion in terms of element size for aluminium plates, a convergence study of residual velocity has been carried out by varying mesh density in the impact zone. Using the preferred material and meshing criteria arrived at here, extremely good prediction of test residual velocities and ballistic limits given by Gupta et al. (2001) for thin aluminium plates has been obtained. The simulation-based pattern of failure with localized bulging and jagged edge of perforation is similar to the perforation with petalling seen in tests. A number of simulation-based parametric studies have been carried out and results consistent with published test data have been obtained. Despite the robust correlation achieved against published experimental results, it would be prudent to conduct one's own experiments, for a final correlation via the present modelling procedure and analysis with the explicit LS-DYNA 970 solver. Hence, a sophisticated ballistic impact testing facility and a high-speed camera have been used to conduct additional tests on grade 1100 aluminium plates of 1 mm thickness with projectiles of four different nose shapes. Finally, using the developed numerical simulation procedure, an excellent correlation of residual velocity and failure modes with the corresponding test results has been obtained.

scholarly journals Modeling of Ice-Shedding from ACSR Power Line

2017 ◽  
Vol 67 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Juraj Hrabovský ◽  
Roman Gogola ◽  
Justín Murín ◽  
Tibor Sedlár
Keyword(s):  
Numerical Analysis ◽  
Material Properties ◽  
Double Bundle ◽  
Power Line ◽  
Power Lines ◽  
Jump Height ◽  
Effective Material Properties ◽  
Ice Shedding ◽  
Overhead Power Lines ◽  
The Impact

Abstract In this contribution, the analysis of ice-shedding from Aluminium Conductor Steel Reinforced (ACSR) power lines is presented. The impact of the icing position on the overhead power lines, the resulting jump height, and impact on attachment tension points after ice-shedding is examined. In the numerical simulations the effective material properties of the ACSR conductor is calculated using the homogenisation method. Numerical analysis of one power line and double-bundle power lines with icing over the whole range or only on certain sections of single and double-bundle power lines are performed

scholarly journals Formation and rupture of gas film of antibubble

2020 ◽  
Vol 23 (1) ◽  
pp. 91-104
Author(s):  
Lichun Bai ◽  
Jinguang Sun ◽  
Zhijie Zeng ◽  
Yuhang Ma ◽  
Lixin Bai
Keyword(s):  
Liquid Film ◽  
High Speed ◽  
Liquid Surface ◽  
Single Layer ◽  
Liquid Films ◽  
Droplet Impact ◽  
Liquid Interface ◽  
High Speed Photography ◽  
Merging Process ◽  
The Impact

The formation and rupture of gas film in the process of formation, rupture and coalescence of antibubbles were investigated by high-speed photography. It was found that a gas film will appear and wrap a droplet when the droplet hit a layer of liquid film or foam before impacting the gas-liquid interface. The gas film may survive the impact on the gas-liquid interface and act as the gas film of an antibubble. A multilayer droplet will be formed when the droplet hits through several layer of liquid films, and a multilayer antibubble will be formed when the multilayer droplet impact a gas-liquid interface or a single layer of foam on the liquid surface. The way to generate antibubbles by liquid films will undergo the formation and rupture of gas films. The coalescence of two antibubbles, which shows a similar merging process of soap bubbles, also undergo the rupture and formation of gas films. The rupture of gas film of antibubble caused by aging and impact is also discussed.

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