A Wind Tunnel Study on the Aerodynamic Characteristics of Ice-Accreted Twin Bundled Conductors

2021 ◽  
Author(s):  
Zhiyu Wan ◽  
Dandan Zhang ◽  
Zhenbiao Li ◽  
Shi Mo ◽  
Yu Zhang
Keyword(s):  
Turbulence Intensity ◽  
Transmission Lines ◽  
Weather Conditions ◽  
Aerodynamic Characteristics ◽  
Ice Thickness ◽  
Aerodynamic Coefficients ◽  
Wake Effect ◽  
Aerodynamic Stability ◽  
Wind Turbulence ◽  
Wind Tunnel Study

Galloping of twin bundled overhead conductors accreted by ice is a frequent phenomenon during freezing weather, which may damage the operation of transmission lines. To analyze the galloping behavior of iced conductors, their aerodynamic characteristics must be studied. In this study, models with two different outlines were designed and tested to determine a more suitable ice-accreted conductor testing model. Subsequently, the influences of the conductor type, ice thickness, wind turbulence intensity, and wake effect of the windward conductor on the aerodynamic coefficients of the conductors with crescent-shape ice are investigated. The results show that the strand outline of overhead conductors must be considered to improve the accuracy of aerodynamic tests. With increasing ice thickness, the aerodynamic stability becomes rapidly deteriorated. Under the wind turbulence intensity of 4%, the aerodynamic stability gets the most enhancement. Moreover, different conductor types have little impact on the aerodynamic coefficients. The wake caused by the windward conductor is the leading cause for the twin bundled iced conductors to have weaker aerodynamic stability than a single conductor. The aerodynamic coefficients determined in this study are essential for predicting the galloping amplitudes of ice-accreted twin bundled overhead conductors under different weather conditions.

scholarly journals Galloping Stability and Wind Tunnel Test of Iced Quad Bundled Conductors considering Wake Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xiaohui Liu ◽  
Ming Zou ◽  
Chuan Wu ◽  
Mengqi Cai ◽  
Guangyun Min ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Transmission Lines ◽  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Aerodynamic Coefficients ◽  
Wake Effect ◽  
Aerodynamic Coefficient ◽  
Set Up ◽  
The Stability ◽  
Three Degrees Of Freedom

A new quad bundle conductor galloping model considering wake effect is proposed to solve the problem of different aerodynamic coefficients of each subconductor of iced quad bundle conductor. Based on the quasistatic theory, a new 3-DOF (three degrees of freedom) galloping model of iced quad bundle conductors is established, which can accurately reflect the energy transfer and galloping of quad bundle conductor in three directions. After a series of formula derivations, the conductor stability judgment formula is obtained. In the wind tunnel test, according to the actual engineering situation, different variables are set up to accurately simulate the galloping of iced quad bundle conductor under the wind, and the aerodynamic coefficient is obtained. Finally, according to the stability judgment formula of this paper, calculate the critical wind speed of conductor galloping through programming. The dates of wind tunnel test and calculation in this paper can be used in the antigalloping design of transmission lines.

scholarly journals Wind Tunnel Tests on Aerodynamic Characteristics of Ice-Coated 4-Bundled Conductors

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Li Xin-min ◽  
Nie Xiao-chun ◽  
Zhu Yong-kun ◽  
You Yi ◽  
Yan Zhi-tao
Keyword(s):  
Wind Tunnel ◽  
Great Influence ◽  
Aerodynamic Characteristics ◽  
Coated Conductors ◽  
Ice Thickness ◽  
Ice Accretion ◽  
Aerodynamic Coefficients ◽  
Wind Tunnel Tests ◽  
Moment Coefficient ◽  
The Moment

Wind tunnel tests were carried out to obtain the static aerodynamic characteristics of crescent iced 4-bundled conductors with different ice thicknesses, initial ice accretion angles, bundle spaces, and wind attack angles. The test models were made of the actual conductors and have a real rough surface. Test results show that the influence of wake interference on the drag coefficients of leeward subconductors is obvious. The interference angle range is larger than 20° and the drag coefficient curves of leeward subconductors have a sudden decrease phenomenon at some certain wind attack angles. The absolute value of the lift and moment coefficient increases with the increase of the ice thickness. In addition, the galloping of the iced subconductor may occur at the angle of wind attack near ±20° and the wake increases the moment coefficient. The variation of initial ice accretion angle has a significant influence on the aerodynamic coefficients. The aerodynamic coefficient curves exhibit a “moving” phenomenon at different initial ice accretion angles. The bundle spaces have a great influence on the moment coefficient of leeward thin ice-coated conductors. With the increase of ice thickness, the bundle spaces generally have little influence on the aerodynamic coefficients.

Experimental Study on the Influence Factors of Static Aerodynamic Characteristics of Ice-Coated Commonly Used Conductors

2013 ◽  
Vol 774-776 ◽  
pp. 1227-1231
Author(s):  
Han Jie Huang ◽  
Xin Min Li
Keyword(s):  
Wind Speed ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Influence Factors ◽  
Aerodynamic Characteristics ◽  
Ice Thickness ◽  
Aerodynamic Load ◽  
Coated Conductor ◽  
Sudden Increase ◽  
Aerodynamic Coefficients

For conductors commonly used in the high and ultra-high voltage transmission projects, research was conducted on how ice shape, ice thickness, wind speed and angle of attack affect the static aerodynamic characteristics of ice-coated conductor. The ice shape and the shape of ice-coated conductor are both important factors that determine the aerodynamic characteristics of conductor. Sudden increase of lift coefficient may happen at low angle of attack. Wind speed shows less effect on aerodynamic characteristics of ice-coated conductor with streamlined shape than that of conductor with blunt shape. Under most attack angles, aerodynamic coefficients increase as the ice thickness increases. The aerodynamic load on ice-coated conductor does not increase linearly with the diameter of conductor.

Aerodynamic Forces of Vehicles on the Bridge under Crosswinds

2013 ◽  
Vol 639-640 ◽  
pp. 1206-1209
Author(s):  
Y. Han ◽  
Steve C.S. Cai
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Experimental Results ◽  
Experimental Setup ◽  
Aerodynamic Coefficients ◽  
Aerodynamic Forces ◽  
Wind Turbulence ◽  
Aerodynamic Interference

In the present study, an experimental setup was made to measure the aerodynamic characteristics of vehicles on the bridge for different cases in a wind tunnel considering the aerodynamic interference. The influence of the wind turbulence, the vehicle interference, and the distance of vehicle from the windward edge of the deck on the aerodynamic coefficients of vehicles were investigated based on the experimental results. The measured results showed that the wind turbulence, the vehicle interference, and the vehicle distance from the windward edge significantly affected the aerodynamic coefficients of vehicles.

Optimization of Restoration Paths of Power System after Blackout

2013 ◽  
Vol 347-350 ◽  
pp. 1467-1472
Author(s):  
Wen Wei Huang ◽  
Gang Yao ◽  
Xiao Yan Qiu ◽  
Nian Liu ◽  
Guang Tang Chen
Keyword(s):  
Power System ◽  
Transmission Lines ◽  
Reactive Power ◽  
Minimum Spanning Tree ◽  
Operation Time ◽  
Combinatorial Problem ◽  
Weather Conditions ◽  
Recovery Process ◽  
Point Of View ◽  
Improved Genetic Algorithm

Optimization of restoration paths of power system after blackout is a multi-stage, multi-target, multi-variable combinatorial problem in the power system restoration. This paper presents a reasonable model and effectually method. The proposed model is considered as a typical partial minimum spanning tree problem from the mathematical point of view which considering all kinds of constraints. Improved data envelopment analysis (DEA) was used to get the weight which considering line charging reactive power, weather conditions, operation time and betweenness of transmission lines. The improved genetic algorithm method is employed to solve this problem. Finally, an example is given which proves the strategy of the line restoration can effectively handle the uncertainty of the system recovery process, to guarantee the system successfully restored after the catastrophic accidents.

scholarly journals Ensuring the aerodynamic stability of the long-span bridges through studies in the wind tunnel

2018 ◽  
Vol 245 ◽  
pp. 02001 ◽  
Author(s):  
Evgenii Khrapunov ◽  
Sergei Solovev
Keyword(s):  
Wind Tunnel ◽  
Design Process ◽  
Aerodynamic Characteristics ◽  
Elastic Instability ◽  
Experimental Facility ◽  
Bridge Design ◽  
Aerodynamic Stability ◽  
Long Span Bridges ◽  
Long Span ◽  
Main Ideas

The main ideas of the aerodynamic studies of large bridges are presented in present paper. Main types of aero-elastic instability for bridges with spans over 100 meters are considered. A two-step modeling approach is presented. At the first stage, the aerodynamic characteristics of the span fragment are considered, at the second.stage the characteristics of the whole bridge. Methods for investigation of bridge oscillations in a special-purpose experimental facility – the Landscape Wind Tunnel – are described. Examples of tests with elastic similar models of bridges are given, and measurements to mitigate dangerous oscillations early in the bridge design process are described.

The Study of Wake and Array of Double Wind Turbine

2013 ◽  
Vol 448-453 ◽  
pp. 1707-1711
Author(s):  
Rui Yang ◽  
Wei Wei Xia ◽  
Jin Long Li
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Turbulence Intensity ◽  
Fatigue Load ◽  
Wake Effect ◽  
Wake Field ◽  
Aerodynamic Interaction ◽  
Simulation Results ◽  
Effective Use ◽  
Wind Resources

For the effective use of wind resources, and in order to decrease the wake effect on the performance of wind turbine, a numerical simulation has carried out to the aerodynamic interaction between two rotors coaxial arrangement. At last the numerical simulation results are verified by experiment. The results show that downstream turbine makes the upstream diverging wake to be converged when coaxial arrangement, and the output of downstream turbine is affected by upstream wake when the distance is less than 5D.The wake field become more diffused after pass the downstream turbine, the area of diverging wake become larger than the wake of upstream turbine mainly due to the increase of turbulence intensity. The greater fatigue load will impact on the downstream turbine. At last the simulation results are in well agreement with the experimental results.

Galloping response of sector-shape iced eight bundle conductors

2020 ◽  
Vol 47 (10) ◽  
pp. 1201-1213
Author(s):  
Meng-qi Cai ◽  
Lin-shu Zhou ◽  
Qian Xu ◽  
Xiao-hui Yang ◽  
Xiao-hui Liu
Keyword(s):  
Transmission Lines ◽  
Theoretical Basis ◽  
Wind Tunnel Test ◽  
Dynamic Responses ◽  
Test Results ◽  
The Finite Element Method ◽  
Aerodynamic Coefficients ◽  
Aerodynamic Loads ◽  
Natural Modes ◽  
Wind Velocities

Wind tunnel test results of the aerodynamic coefficients of sector-shape iced eight bundle conductors varying with wind attack angles are presented. Then, by means of the user-defined cable elements, the aerodynamic loads are applied on the cable elements of each sub-conductor through the finite element method (FEM). In addition, the galloping responses of sector-shape iced eight bundle conductors are discussed. Finally, galloping responses, including dynamic responses (natural modes and frequencies), galloping orbits, and amplitudes of typical sector-shape iced eight bundle conductor transmission lines in the cases of different span lengths, wind velocities, and angles of wind attack are studied, respectively. These results provide useful references for a theoretical basis for the study of galloping and the technique of anti-galloping in cold regions.

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