scholarly journals Study on Adaptive Excitation System of Transmission Line Galloping Based on Electromagnetic Repulsive Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Jiangjun Ruan ◽  
Li Zhang ◽  
Wei Cai ◽  
Daochun Huang ◽  
Jian Li ◽  
...  
Keyword(s):  
Transmission Line ◽  
Aerodynamic Force ◽  
Weather Conditions ◽  
Element Model ◽  
Test System ◽  
Transmission Tower ◽  
Excitation System ◽  
Line System ◽  
Integrated Simulation ◽  
Excitation Method

Due to the uncontrollable weather conditions, it is difficult to carry out the controllable prototype test to study fatigue damage of transmission tower and armour clamp and the effect evaluation of antigalloping device under actual transmission line galloping. Considering the geometric nonlinearity of the transmission line system, this study proposed an adaptive excitation method to establish the controllable transmission line galloping test system based on the Den Hartog vertical oscillation mechanism. It can skip the complicated process of nonlinear aerodynamic force simulation. An electromagnetic repulsion mechanism based on the eddy current principle was designed to provide periodic excitation for the conductor system according to the adaptive excitation method. The finite element model, including conductor, insulator string, and electromagnetic mechanism, was established. Newmark method and fourth-order Runge-Kutta algorithm were used to complete the integrated simulation calculation. By comparing with the measured data record of the actual transmission line galloping test, the results show that the proposed adaptive galloping excitation system can effectively reconstruct the key characteristics of the actual transmission line galloping, such as amplitude, frequency, galloping mode, and dynamic tension, and make the galloping state controllable. Thus, a series of research about transmission line galloping with practical engineering significance can be carried out.

Finite Element Analysis for the Collapse Accident of One 110kV Transmission Tower

2013 ◽  
Vol 690-693 ◽  
pp. 1940-1944
Author(s):  
Ming Jian Jian ◽  
Du Qing Zhang ◽  
Guang Cheng Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Transmission Line ◽  
Element Model ◽  
Strong Wind ◽  
Transmission Tower ◽  
Element Analysis ◽  
Line System ◽  
Buckling Instability

One collapse tower of 110 kV transmission line was taken as an example and a finite element model for the coupled tower-line system was established for investigating the effects of the strong wind on the transmission tower and line. The result shows that the selected standard of material of some rod members is lower, and the area of their section is relatively small. Main legs present buckling instability because of being in compression under action of the strong wind, which leads to the collapse accident of the towers.

scholarly journals Collapse Analysis of a Transmission Tower-Line System Induced by Ice Shedding

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaxiang Li ◽  
Biao Wang ◽  
Jian Sun ◽  
Shuhong Wang ◽  
Xiaohong Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Transmission Lines ◽  
Progressive Collapse ◽  
Element Model ◽  
Transmission Tower ◽  
Line System ◽  
Finite Element Software ◽  
Transmission Towers ◽  
Ice Shedding ◽  
The Impact

Ice shedding causes transmission lines to vibrate violently, which induces a sharp increase in the longitudinal unbalanced tension of the lines, even resulting in the progressive collapse of transmission towers in serious cases, which is a common ice-based disaster for transmission tower-line systems. Based on the actual engineering characteristics of a 500 kV transmission line taken as the research object, a finite element model of a two-tower, three-line system is established by commercial ANSYS finite element software. In the modeling process, the uniform mode method is used to introduce the initial defects, and the collapse caused by ice shedding and its influencing parameters are systematically studied. The results show that the higher the ice-shedding height is, the greater the threat of ice shedding to the system; furthermore, the greater the span is, the shorter the insulator length and the greater the dynamic response of the line; the impact of ice shedding should be considered in the design of transmission towers.

scholarly journals The Effect Analysis of Strain Rate on Power Transmission Tower-Line System under Seismic Excitation

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Li Tian ◽  
Wenming Wang ◽  
Hui Qian
Keyword(s):  
Strain Rate ◽  
Power Transmission ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Seismic Excitation ◽  
Transmission Tower ◽  
Base Shear ◽  
Effect Analysis ◽  
Line System

The effect analysis of strain rate on power transmission tower-line system under seismic excitation is studied in this paper. A three-dimensional finite element model of a transmission tower-line system is created based on a real project. Using theoretical analysis and numerical simulation, incremental dynamic analysis of the power transmission tower-line system is conducted to investigate the effect of strain rate on the nonlinear responses of the transmission tower and line. The results show that the effect of strain rate on the transmission tower generally decreases the maximum top displacements, but it would increase the maximum base shear forces, and thus it is necessary to consider the effect of strain rate on the seismic analysis of the transmission tower. The effect of strain rate could be ignored for the seismic analysis of the conductors and ground lines, but the responses of the ground lines considering strain rate effect are larger than those of the conductors. The results could provide a reference for the seismic design of the transmission tower-line system.

Gust Response Factor of a Transmission Tower Under Typhoon

2020 ◽  
pp. 2150001
Author(s):  
Xing Fu ◽  
Wen-Long Du ◽  
Hong-Nan Li ◽  
Wen-Ping Xie ◽  
Kai Xiao ◽  
...  
Keyword(s):  
Wind Speed ◽  
Field Measurements ◽  
Element Model ◽  
Structural Safety ◽  
Transmission Tower ◽  
Response Factors ◽  
Line System ◽  
Transmission Towers ◽  
Synoptic Wind ◽  
Gust Response

The gust response factors (GRFs) of transmission towers in current standards are reviewed for synoptic winds. The collapse of most transmission towers has occurred under the high-intensity wind (HIW) caused by events such as typhoons, hurricanes, and downbursts. Thus, this paper studies the GRF of a transmission tower under the typhoon. First, the definition of GRF and its extended form for the transmission towers are developed. Then the wind speed simulation of a typhoon event is introduced. Based on the structural health monitoring (SHM) system installed on tower #32, the measured GRFs under the super typhoon Mangkhut are calculated. Then the finite element model (FEM) of the transmission tower-line system is established to simulate the dynamic response to further calculate the GRFs, which agrees well with the field measurements. Both the field measurement and simulation results show that the GRFs under the typhoon are larger than those under the synoptic wind and that the recommended GRFs in the Chinese standard underestimate the peak responses. Finally, a parametric analysis is performed, which demonstrates that the turbulence intensity, wind speed, and power-law exponent all have great effects on the GRFs of transmission towers. In the HIW-prone areas, it is recommended that the characteristics of the HIW can be considered in improving the GRF values to guarantee the structural safety of transmission towers.

Fragility analysis of a long-span transmission tower–line system under wind loads

2020 ◽  
Vol 23 (10) ◽  
pp. 2110-2120
Author(s):  
Li Tian ◽  
Xin Zhang ◽  
Xing Fu
Keyword(s):  
Damage Index ◽  
Element Model ◽  
Attack Angle ◽  
Fragility Analysis ◽  
Wind Loads ◽  
Collapse Mechanism ◽  
Ultimate Capacity ◽  
Transmission Tower ◽  
Line System ◽  
Long Span

Numerous transmission towers have collapsed due to experiencing strong winds; therefore, the purpose of this article is to investigate the collapse mechanism and the anti-collapse performance of a long-span transmission tower–line system. The detailed finite element model of a typical tower–line system is established in ABAQUS. A global damage index is proposed to quantitatively estimate the overall damage of the structure and define the collapse criteria. An incremental dynamic analysis is performed to obtain the collapse mechanism and the ultimate capacity of the structure. Subsequently, a fragility analysis for evaluating the anti-collapse performance is conducted due to the uncertainty of wind loads. Eventually, the influence of the wind attack angle and the length of the side spans on the fragility is discussed. The results demonstrate that the proposed global damage index is capable of quantitatively reflecting the overall damage and assessing the ultimate capacity of the structure. In addition, the uncertainty of the wind load has a significant influence on the ultimate capacity and the failure position. Furthermore, the results reveal that the wind attack angle and the length of the side spans have an apparent effect on the fragility of the structure.

A Bidirectional Pounding Tuned Mass Damper and Its Application to Transmission Tower-Line Systems under Seismic Excitations

2019 ◽  
Vol 19 (06) ◽  
pp. 1950056 ◽  
Author(s):  
Li Tian ◽  
Kunjie Rong ◽  
Kaiming Bi ◽  
Peng Zhang
Keyword(s):  
Element Model ◽  
Tuned Mass Damper ◽  
Seismic Intensity ◽  
Design Parameters ◽  
Seismic Responses ◽  
Transmission Tower ◽  
Control Effect ◽  
Seismic Excitations ◽  
Line System ◽  
Mass Damper

Failures of transmission tower-line systems have frequently occurred during large earthquakes. It is essential to control the excessive vibrations of transmission tower-line systems to ensure their safe operation in such events. This paper numerically investigates the effectiveness of using a novel bidirectional pounding tuned mass damper (BPTMD) to control the seismic responses of transmission tower-line system when subjected to earthquake ground motions. A finite element model of a typical transmission tower-line system with BPTMD is developed using the commercial software ABAQUS, with the accuracy of the results verified against a previous study. The seismic responses of the system with and without BPTMD are calculated. For comparison, the control effect of using the conventional bidirectional tuned mass damper is also calculated and discussed. Finally, a parametric study is performed to investigate the effects of the mass ratio, seismic intensity, gap size and frequency ratio on the seismic response of the system, while optimal design parameters are obtained.

scholarly journals Nonlinear Seismic Behavior of Different Boundary Conditions of Transmission Line Systems under Earthquake Loading

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Li Tian ◽  
Xia Gai
Keyword(s):  
Boundary Conditions ◽  
Transmission Line ◽  
Transmission Lines ◽  
Seismic Analysis ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Earthquake Loading ◽  
Transmission Tower ◽  
Line System ◽  
Different Boundary Conditions

Nonlinear seismic behaviors of different boundary conditions of transmission line system under earthquake loading are investigated in this paper. The transmission lines are modeled by cable element accounting for the nonlinearity of the cable. For the suspension type, three towers and two span lines with spring model (Model 1) and three towers and four span lines’ model (Model 2) are established, respectively. For the tension type, three towers and two span lines’ model (Model 3) and three towers and four span lines’ model (Model 4) are created, respectively. The frequencies of the transmission towers and transmission lines of the suspension type and tension type are calculated, respectively. The responses of the suspension type and tension type are investigated using nonlinear time history analysis method, respectively. The results show that the responses of the transmission tower and transmission line of the two models of the suspension type are slightly different. However, the responses of transmission tower and transmission line of the two models of the tension type are significantly different. Therefore, in order to obtain accurate results, a reasonable model should be considered. The results could provide a reference for the seismic analysis of the transmission tower-line system.

Wind-Induced Vibration Control for Transmission System Using Steel-Lead Viscoelastic Damper

2014 ◽  
Vol 597 ◽  
pp. 376-379 ◽  
Author(s):  
Feng Lin Gan ◽  
Hai Long Jiang
Keyword(s):  
Time History ◽  
Element Model ◽  
Transmission Tower ◽  
Viscoelastic Damper ◽  
Line System ◽  
Type Steel ◽  
New Type ◽  
Auto Regressive ◽  
Working Principle ◽  
Wind Induced Vibration

For wind-induced vibration of transmission tower-line system, the vibration reduction effects are studied based on a new type steel-lead viscoelastic damper. Firstly, Calculate damped coefficient basing on the test of the new type steel-lead viscoelastic damper under slow reversed cyclic horizontal loads. Then, a finite element model of transmission tower was built by using ANSYS. And the time history samples of random fluctuating wind load is obtained with the linear auto-regressive filter law principle. Next, three installation plans of dampers on tower were proposed based on analyzing the working principle damper and the structure of tower. Finally, a wind-induced vibration transient response simulation was performed respectively for the different plans. The influences of SLVD dampers on the displacement and on the acceleration of the controlled nodes were compared. SLVD damper can reduce the top node displacement by about 37.89%. The results indicated that the SLVD damper can suppress the wind-induced vibration. And through comparison, the optimal installation scheme of SLVD dampers is obtained.

Abnormal Image Monitoring for Transmission Line Based on Digital Image Processing

2013 ◽  
Vol 710 ◽  
pp. 613-616
Author(s):  
Chun Jie Wang ◽  
Bo Xiang Xin
Keyword(s):  
Image Processing ◽  
Transmission Line ◽  
Digital Image Processing ◽  
High Voltage ◽  
Transmission Tower ◽  
Line System ◽  
High Voltage Transmission Line ◽  
Transmission Line Method ◽  
Image Monitoring ◽  
High Voltage Transmission

In the high-voltage transmission line system, the accidents have often occurred, and as a result of power line icing accidents are particularly prominent. In this paper, the author presents a DSP-based image monitoring of high voltage transmission line method. This method is use of high-voltage transmission tower-lines camera to collect the high voltage transmission line image in real time, and directly processing the image in DSP. If wires normal, it will not send pictures to the center and if the abnormal occurred, it will calculate the thickness of ice covering wires, converting the image to JPEG. This article designed and implemented the DSP-based image monitoring of high voltage transmission line algorithm exception, run successfully in the simulation and emulation system which can be used for monitoring of high voltage transmission line icing conditions online.

scholarly journals Investigation and Development of a Three-Dimensional Transmission Tower-Line System Model Using Nonlinear Truss and Elastic Catenary Elements for Wind Loading Dynamic Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-29
Author(s):  
Xiao Zhu ◽  
Ge Ou
Keyword(s):  
Transmission Line ◽  
Open Source ◽  
Three Dimensional ◽  
Initial Strain ◽  
Wind Loading ◽  
Transmission Line Model ◽  
Transmission Tower ◽  
Line Model ◽  
Line System ◽  
Truss Element

The accuracy of transmission tower-line system simulation is highly impacted by the transmission line model and its coupling with the tower. Owing to the high geometry nonlinearity of the transmission line and the complexity of the wind loading, such analysis is often conducted in the commercial software. In most commercial software packages, nonlinear truss element is used for cable modeling, whereas the initial strain condition of the nonlinear truss under gravity loading is not directly available. Elastic catenary element establishes an analytical formulation for cable structure under distributed loading; however, the nonlinear iteration to reach convergence can be computational expensive. To derive an optimal transmission tower-line model solution with high fidelity and computational efficiency, an open-source three-dimensional model is developed. Nonlinear truss element and elastic catenary element are considered in the model development. The results of the study imply that both elements are suitable for the transmission line model; nevertheless, the initial strain in nonlinear truss element largely impacts the model accuracy and should be calibrated from the elastic catenary model. To cross-validate the developed models on the coupled transmission tower and line, a one-span eight-line system is modeled with different elements and compared with several state-of-the-art commercial packages. The results indicate that the displacement time-history root-mean-square error (RMSE) of the open-source transmission tower-line model is less than 1 % and with a 66 % computational time reduction compared with the ANSYS model. The application of the open-source package transmission tower-line model on extreme wind speed considering the aerodynamic damping is further implemented.

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