Simulation and Experiential Research for Broken Conductor Load of Suspension Towers of UHVDC Power Transmission

2012 ◽  
Vol 249-250 ◽  
pp. 798-803
Author(s):  
Zi Fu Zhang ◽  
Zeng Lu Mo ◽  
Jing Du Geng

The breakage of conductor/ground wire seriously affects the secure operation of transmission line. According to the features of UHVDC power transmission lines, the broken conductor model for bundled conductors of continuous span is built and the broken conductor load is calculated; A simulating test was carried out the first time in China for a series of "broken conductor" events on one continuous span on the field to study the dynamic response of the transmission tower because of impact, then the dynamic strain and displacement were obtained. On the basis of the simulation and experiential research results, the paper discussed about the rational values of broken wire loads for the suspension towers of UHVDC.

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1561
Author(s):  
Hao Chen ◽  
Zhongnan Qian ◽  
Chengyin Liu ◽  
Jiande Wu ◽  
Wuhua Li ◽  
...  

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.


Author(s):  
Guanghong Tao ◽  
Lijin Fang

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.


2017 ◽  
Vol 40 (11) ◽  
pp. 3273-3292 ◽  
Author(s):  
Vikram Banthia ◽  
Yaser Maddahi ◽  
Kourosh Zareinia ◽  
Stephen Liao ◽  
Tim Olson ◽  
...  

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.


Author(s):  
Ngo Minh Khoa ◽  
Nguyen Huu Hieu ◽  
Dinh Thanh Viet

<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>


Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1193 ◽  
Author(s):  
Zuzana Bukvisova ◽  
Jaroslava Orsagova ◽  
David Topolanek ◽  
Petr Toman

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.


2013 ◽  
Vol 732-733 ◽  
pp. 1045-1051 ◽  
Author(s):  
Qing Hua Li ◽  
Jing Bo Yang ◽  
Jun Ke Han

State Grid Corporation of China has carried out research on key technology of UHV&EHV AC and DC multi-circuit transmission lines, the research on material and structure of transmission tower is the important part. The SSZT2 tower, on which 1000 kV AC double-circuit and 500 kV AC double-circuit are arranged, is the largest power transmission capacity all over the world. Q420 high-strength tubular steel, the plug-in boards and forging flanges are used in SSZT2 tower,and the forging flange with strength classification is applied for the first time. Through the monographic study on the tower structures, wind vibration coefficient, and biaxial bending of steel tube etc. The success of full-scale test verified the reliability in design and manufacture of multi-circuit steel tubular tower for UHV and EHV. Research results of this paper can be applied in UHV transmission line projects.


2013 ◽  
Vol 333-335 ◽  
pp. 2123-2129
Author(s):  
Xiao Hui Yang ◽  
Bo Zhang ◽  
Wen Juan Lou ◽  
Zheng Cai Fu

With transmission line galloping occurring frequently in recent years, the phenomenon of tower damaged by galloping has become more and more serious, even with the whole tower collapsed during galloping. According to the statistic and analysis on the towers in 500kV transmission line of Henan power grid, which had been damaged by the galloping accidents in the winter of 2009 to 2010, The galloping section of 500kV Kai-Xiang Line with the typical impaired character had been selected for laboratory modeling and test. Through a series of tests, the maximum loading position and the vibration model for tower had been found, and the changing character of towers dynamic response with ice thickness, galloping amplitude and frequency analyzed. The loading-endurance character of rod and bolts joint, as the major components of tower, had been tested and analyzed respectively. The bolts joints, had been proved as the weakest point for galloping-endurance performance of the whole tower. The study stated in this paper would provide guidance and suggestion to the alteration on galloping prevention and controlling for transmission line. It was also shown that, developing the study on the locking performance of bolts joints on tower is quite essential.


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