Dynamic Analysis of Power Transmission Lines With Ice-Shedding Using an Efficient Absolute Nodal Coordinate Beam Formulation

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Wei Fan ◽  
Hui Ren ◽  
Weidong Zhu ◽  
Hao Zhu
Keyword(s):  
Dynamic Analysis ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Bending Stiffness ◽  
Dynamic Responses ◽  
Power Transmission Lines ◽  
Absolute Nodal Coordinate ◽  
Generalized Coordinates ◽  
Ice Shedding

Abstract Dynamic analysis of power transmission lines with ice-shedding is conducted in this work. The power transmission line is first simplified as a uniform slender round beam. While the beam can have large displacements, rotations, and deformations, its strains are assumed to be small. The bending stiffness of the transmission line is considered here, but its shear and torsion effects are neglected. An efficient absolute nodal coordinate beam formulation is developed based on the above assumptions, and the number of generalized coordinates of each element of the beam is reduced to the least. The mass matrix is constant and the generalized elastic force is evaluated by constant stiffness tensors and generalized coordinates; hence, the current formulation is very efficient. Dynamic responses of power transmission lines with ice-shedding are then calculated. A benchmark planar two-span line is first considered, and the results are validated by the commercial finite element software abaqus. By examining strain states of the transmission line, it is found that its bending stiffness cannot be neglected in this dynamic analysis. Dynamic analysis of a three-dimensional three-span line is then conducted, where towers are not in a straight line and elevation differences between adjacent towers are considered. Several cases with common ice detachment mechanisms are considered, and dynamic responses of the cable and reaction forces of insulators due to ice-shedding are analyzed.

Cable rime accretion measurements on a Laurentian mountain

1990 ◽  
Vol 17 (6) ◽  
pp. 1022-1032 ◽  
Author(s):  
Pierre McComber ◽  
Jacques Druez ◽  
Béatrice Félin
Keyword(s):  
Transmission Line ◽  
Wind Velocity ◽  
Transmission Lines ◽  
Power Transmission ◽  
Winter Season ◽  
Similar Data ◽  
Power Transmission Lines ◽  
Mountain Ranges ◽  
Ice Shedding ◽  
Set Up

Rime is an important cause of damage to structures in northern Quebec, Canada, and a major concern about the reliability of power transmission lines. An atmospheric icing test line was set up at Mt. Valin (altitude 902 m), near Chicoutimi, to measure icing rates on stranded cables. Two cables, the first one 96.5 m (316.5 ft) in span and the second one 32.6 m (106.9 ft), were used to investigate transmission line icing by comparing icing, for a complete winter, on two stranded cables, 35 mm (1.38 in.) in diameter for the first cable and 8 mm (0.315 in.) for the second. Measurements taken during the 1986–1987 winter season are analyzed. Ice accretion and shedding are correlated with ice detector alarms and wind velocity respectively. The icing intensity, considered to be proportional to the number of icing alarms per unit time, is strongly correlated with the cable icing rate. A significant correlation is also verified between the wind velocity and the ice shedding. Results of this investigation indicate that wind velocity and icing detector alarm rate are important variables to predict total ice mass on cables exposed to winter in-cloud icing. With more similar data, the implementation of an empirical icing model to estimate cable icing in mountain ranges will become possible. Key words: transmission line icing, rime accretion, ice shedding.

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.

Half-Critical Response of Cylindrical Rotor to Distributed Elasticity Excitation

2005 ◽  
Author(s):  
Erno Keskinen ◽  
Michel Cotsaftis ◽  
Matti Martikainen
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Formal Solution ◽  
Resonance State ◽  
Bending Stiffness ◽  
Power Transmission Lines ◽  
Rayleigh Beam ◽  
Manufacturing Accuracy ◽  
Modal Coordinates ◽  
Stiffness Distribution

Due to the limitations of manufacturing accuracy, long cylindrical rotors used in heavy power transmission lines and paper machinery are dynamically excited by internal elastic forces. The origin of these forces is the out-of-roundness profile of the inner and outer radii of the rotor, which contributes to the bending stiffness distribution along the rotor span. Distributed anisotropy of the rotor under gravitational load is reason of the existence of half-critical speeds, on which the rotor experiences non-classical resonance state. This problem has been formulated in terms of nominal and deviated motion according to the splitting of the bending stiffness tensor in a similar way. This leads to a static rotor equation, whose amplification effect on to the dynamic part of the motion has been analyzed in details. This includes formal solution of the resulting dynamic Hill equation in terms of the modal coordinates of the corresponding free whirling Rayleigh beam.

scholarly journals A prototype telerobotic platform for live transmission line maintenance: Review of design and development

2017 ◽  
Vol 40 (11) ◽  
pp. 3273-3292 ◽  
Author(s):  
Vikram Banthia ◽  
Yaser Maddahi ◽  
Kourosh Zareinia ◽  
Stephen Liao ◽  
Tim Olson ◽  
...  
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Communication Channel ◽  
Force Feedback ◽  
Power Transmission ◽  
Objective Evaluation ◽  
Test Facility ◽  
Task Completion ◽  
Power Transmission Lines ◽  
Virtual Fixture

This paper reports technical design of a novel experimental test facility, using haptic-enabled teleoperation of robotic manipulators, for live transmission line maintenance. The goal is to study and develop appropriate techniques in repair overhead power transmission lines by allowing linemen to wirelessly guide a remote manipulator, installed on a crane bucket, to execute dexterous maintenance tasks, such as twisting a tie wire around a cable. Challenges and solutions for developing such a system are outlined. The test facility consists of a PHANToM Desktop haptic device (master site), an industrial hydraulic manipulator (slave site) mounted atop a Stewart platform, and a wireless communication channel connecting the master and slave sites. The teleoperated system is tested under different force feedback schemes, while the base is excited and the communication channel is delayed and/or lossy to emulate realistic network behaviors. The force feedback schemes are: virtual fixture, augmentation force and augmented virtual fixture. Performance of each scheme is evaluated under three measures: task completion time, number of failed trials and displacement of the slave manipulator end-effector. The developed test rig has been shown to be successful in performing haptic-enabled teleoperation for live-line maintenance in a laboratory setting. The authors aim at establishing a benchmark test facility for objective evaluation of ideas and concepts in the teleoperation of live-line maintenance tasks.

scholarly journals A Study of SVC’s Impact Simulation and Analysis for Distance Protection Relay on Transmission Lines

2017 ◽  
Vol 7 (4) ◽  
pp. 1686
Author(s):  
Ngo Minh Khoa ◽  
Nguyen Huu Hieu ◽  
Dinh Thanh Viet
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Power Transmission Lines ◽  
Distance Protection ◽  
Protection Relay ◽  
Impact Simulation ◽  
Relay Location ◽  
Measured Impedance ◽  
Distance Protection Relay

<p>This paper focuses on analyzing and evaluating impact of a Static Var Compensator (SVC) on the measured impedance at distance protection relay location on power transmission lines. The measured impedance at the relay location when a fault occurs on the line is determined by using voltage and current signals from voltage and current transformers at the relay and the type of fault occurred on the line. The MHO characteristic is applied to analyze impact of SVC on the distance protection relay. Based on the theory, the authors in this paper develop a simulation program on Matlab/Simulink software to analyze impact of SVC on the distance protection relay. In the power system model, it is supposed that the SVC is located at mid-point of the transmission line to study impact of SVC on the distance relay. The simulation results show that SVC will impact on the measured impedance at the relay when the fault occurs after the location of the SVC on the power transmission line.</p>

scholarly journals Two-Terminal Algorithm Analysis for Unsymmetrical Fault Location on 110 kV Lines

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1193 ◽  
Author(s):  
Zuzana Bukvisova ◽  
Jaroslava Orsagova ◽  
David Topolanek ◽  
Petr Toman
Keyword(s):  
Power Systems ◽  
Transmission Line ◽  
Transmission Lines ◽  
Computer Aided Design ◽  
Fault Location ◽  
Power Transmission ◽  
Current Data ◽  
Algorithm Analysis ◽  
Power Transmission Lines ◽  
Design Environment

This work analyses a two-terminal algorithm designed to locate unsymmetrical faults on 110 kV power transmission lines. The algorithm processes synchronized voltage and current data obtained from both ends of the protected transmission line and calculates the distance of the fault. It is based on decomposing the equivalent circuit into the positive-, negative- and zero-sequence components and finding the point where the output voltages of the right and the left side of the transmission line are equal. Compared to the conventional distance relay locator, the accuracy of this method is higher and less influenced by the fault resistance, the parallel-operated line effect and line asymmetry, as discussed in this work. It is, however, very sensitive to the synchronization accuracy. The mathematical model of the power system was created in the PSCAD (Power Systems Computer Aided Design) environment and the computational algorithm was implemented in Mathematica software.

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