Ice Accretion Cause and Mechanism of Glaze on Wires of Power Transmission Lines

2011 ◽  
Vol 189-193 ◽  
pp. 3238-3242 ◽  
Author(s):  
Chun Cheng Liu ◽  
Jiao Liu
Keyword(s):  
Electric Field ◽  
Fluid Mechanics ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Ice Accretion ◽  
Power Transmission Lines ◽  
Field Coupling ◽  
Ice Disaster ◽  
Current Electric Field

The cause of ice accretion of transmission line and ice accretion mechanism are both summarized systematically. The mechanism of ice coating of wire caused by thermodynamics, fluid mechanics and the current electric field coupling is pointed out. In connection with the process of glaze ice, the existing models at home and abroad for the prediction of height and thickness of ice coating are summarized and analyzed, it can give some advises on further study of ice accretion prediction and some lights on ice disaster and anti-icing design for power transmission lines.

Influence of Icing to the Corona Loss Characteristics of the AC Power Transmission Lines

2013 ◽  
Vol 385-386 ◽  
pp. 1112-1116
Author(s):  
Jun Zhu ◽  
Zi Qiang Xu ◽  
Qing Zhong Geng ◽  
Yun Peng Liu ◽  
Jiang Hai Geng
Keyword(s):  
Electric Field ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Experimental Results ◽  
Power Transmission Lines ◽  
Ac Power ◽  
Test Platform ◽  
Surface Electric Field ◽  
Simulation Results

The transmission line corridor will inevitably cross the icing area in China. Icing will influence the corona characteristics of transmission lines. In order to deeply analyze the influence law of the icing to corona loss characteristics, an icing test platform that can be utilized to simulate icing conditions was built. Icing test was done in the corona cage of 1.8m×1.8m×4m. Through changing the conductivity of freezing water and the length of icicle, corona loss of the icing conductor was measured and the surface electric field was also simulated with the software ANSYS. The results show that the length of icicle is an important factor affecting the corona loss of the AC conductor and the conductivity of freezing water on that impact is not obvious. Owing to the icicles, the distortion of the conductor electric field is serious. With the increase of icicle length, conductor corona loss value increases significantly. When the length of icicle increases to about 18mm, the increase of the corona loss value is no longer obvious trending to be saturated . The simulation results coincided with the experimental results very well.

scholarly journals Enhanced analytical model of power transmission line icing

2018 ◽  
Vol 11 (3) ◽  
pp. 222-226
Author(s):  
M. V. Timofeeva
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Transmission Line ◽  
Analytical Model ◽  
Transmission Lines ◽  
Wind Direction ◽  
Power Transmission ◽  
Weather Conditions ◽  
Power Transmission Line ◽  
Power Transmission Lines

Accidents in power transmission lines under icing conditions, in particular, those of cables, cause a great economic damage in Russia. Because of the lack of the possibility to forecast and evaluate reliably the consequences of weather conditions contributing to icing of transmisison line cables, power grid services often have to go to the place of a potential accident relying on guesswork. This leads to considerable losses of time and material resources, while the average recovery time of a damaged high voltage power transmission line is 5–10 days.For the effective prediction and timely prevention of negative consequences of icing of on power line cables, an analytical model that describes the growth of ice on the surface of the electrical cable has been developed. The model is based on a widely applicable analytical model of [1], supplemented with dependence of the growth of ice sleeve on the angle between the wind direction and the cable, and on the electric field strength of the cable.The results obtained using the new analytical model and the [1], model have been compared and show that as the angle between the wind direction and the cable decreases, the intensity of the ice growth decreases significantly. At the same time, the strength of the electric field of the cable affects negligibly the trajectory of water droplets.A conclusion is drawn about insignificance of electrical field strength of the electric cable as a factor of growth of ice deposits. It is stated that the ice thickness value obtained using the developed model can be increased under specific weather conditions and design parameters of transmission lines. The obtained model can be improved by using other physical effects that affect icing of electric cables. Further, the model can be introduced in operation of energy companies to monitor the condition of power transmission lines and to carry out anti-icing activities.

scholarly journals Time-Multiplexed Self-Powered Wireless Current Sensor for Power Transmission Lines

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1561
Author(s):  
Hao Chen ◽  
Zhongnan Qian ◽  
Chengyin Liu ◽  
Jiande Wu ◽  
Wuhua Li ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Current Measurement ◽  
Current Sensor ◽  
Power Transmission Line ◽  
Power Transmission Lines ◽  
Current Sensing ◽  
Self Powered

Current measurement is a key part of the monitoring system for power transmission lines. Compared with the conventional current sensor, the distributed, self-powered and contactless current sensor has great advantages of safety and reliability. By integrating the current sensing function and the energy harvesting function of current transformer (CT), a time-multiplexed self-powered wireless sensor that can measure the power transmission line current is presented in this paper. Two operating modes of CT, including current sensing mode and energy harvesting mode, are analyzed in detail. Through the design of mode-switching circuit, harvesting circuit and measurement circuit are isolated using only one CT secondary coil, which eliminates the interference between energy harvesting and current measurement. Thus, the accurate measurement in the current sensing mode and the maximum energy collection in the energy harvesting mode are both realized, all of which simplify the online power transmission line monitoring. The designed time-multiplexed working mode allows the sensor to work at a lower transmission line current, at the expense of a lower working frequency. Finally, the proposed sensor is verified by experiments.

A multi-unit serial inspection robot for power transmission lines

2019 ◽  
Vol 46 (2) ◽  
pp. 223-234 ◽  
Author(s):  
Guanghong Tao ◽  
Lijin Fang
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Power Transmission Line ◽  
The Novel ◽  
Power Transmission Lines ◽  
Obstacle Crossing ◽  
Content Type ◽  
Inspection Robot ◽  
Serial Robot

Purpose The purpose of this paper is to introduce a robot mechanism designed for power transmission line inspection. The focus for this design is on obstacle-crossing ability with a goal to create a robot moving and crossing obstacle on not only the straight line but also the steering line. Design/methodology/approach A novel four-unit tri-arm serial robot mechanism is proposed. Every novel unit designed for pitching motion is based on parallelogram structure, which is driven by cables and only one motor. There is gripper-wheel compounding mechanism mounted on the arm. The prototype and obstacle environments are established, and the obstacle-crossing experiments are conducted. Findings The novel unit mechanism and robot prototype have been tested in the lab. The prototype has demonstrated the obstacle-crossing ability when moving and crossing fundamental obstacles on the line. The experimental results show that the robot mechanism meets the obstacle-crossing requirements. Practical implications The novel robot technology can be used for defect inspection of power transmission line by power companies. Social implications It stands to lower the intense and risk of inspection works and reduce the costs related to inspection. Originality/value Innovative features include its architecture, mobility and driving method.

Experimental Researches on Micro-Droplet Freezing on a Solid Surface Under Atmospheric Conditions: Part I

2008 ◽  
Author(s):  
Heyun Liu ◽  
Xiaohui Ma
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Electrostatic Force ◽  
Droplet Diameter ◽  
Ccd Camera ◽  
Freezing Process ◽  
Ice Accretion ◽  
Power Transmission Lines ◽  
Atmospheric Conditions ◽  
Air Stream

Atmospheric ice accretion on structures is a problem of fundamental importance to a number of industries. Examples of engineering problems caused by ice accretion involving aircraft, power transmission lines, telecommunication towers, electrical railway contact-wires, and other structures. Under atmospheric icing conditions two basic types of ice may form; rime or glaze. The supercooled micro-droplets in clouds are an important factor in icing. The objective of this study was to develop a new experimental method to investigate a single supercooled micro-droplet freezing process, in order to better understand the mechanism of rime or glaze ice accretion. The experimental device and principles are described in this paper. The experimental set has two small cold rooms, which is separated by a board with a central hole. A droplet with diameter of 15∼40 μm, temperature of 0∼−5°C was levitated in the cold air stream by electrostatic force. A CCD camera tracked its trace. The air temperature is from 0∼−10°C, the micro-droplet diameter is from 15∼40μm, and its temperature is from 0∼−5°C in the experimental study. This article focused on the experimental set and the experimental principles, and the next article will focus on the experimental data analysis.

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