scholarly journals Modeling and Analysis of Progressive Ice Shedding along a Transmission Line during Thermal De-Icing

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yunyun Xie ◽  
Linyan Huang ◽  
Da Wang ◽  
Huaiping Ding ◽  
Xiaochun Yin
Keyword(s):  
Dynamic Response ◽  
Transmission Line ◽  
Transmission Lines ◽  
Dynamic Equilibrium ◽  
Propagation Speed ◽  
Experimental Results ◽  
Small Scale ◽  
Equilibrium Equations ◽  
Modeling And Analysis ◽  
Ice Shedding

Progressive ice shedding (PIS) along transmission lines is a common type of ice shedding during thermal de-icing that requires investigation to ensure the security of transmission lines. In current research, PIS is commonly analyzed using a constant speed for ice detaching from the conductor, which is not accurate for PIS simulation. Therefore, a mechanical model of PIS is established in this study to analyze PIS during thermal de-icing. First, an ice detachment model during thermal de-icing is built to determine the detachment times of the initial ice and remaining ice. Then, a two-node isoparametric truss element is employed to derive the static and dynamic equilibrium equations of an iced conductor to simulate the dynamic response of PIS. Relative to commercial software, these equations can easily accommodate the changing mass of ice with the flow of melted water. The dynamic equilibrium equations are then solved using the ice detachment model to obtain the dynamic response of PIS. Finally, small-scale and full-scale experimental results are employed to verify the proposed method. The simulation results show that the results of the proposed method are more consistent with the experimental results than are the results of existing methods that assume a constant propagation speed. The proposed method can be further applied to optimize transmission line designs and evaluate the application of thermal de-icing devices.

Dynamic Response Analysis of Bridge Pier Subject to Earthquake and Ice Loads

2011 ◽  
Vol 250-253 ◽  
pp. 2211-2215
Author(s):  
Fu Qiang Qi
Keyword(s):  
Dynamic Response ◽  
Dynamic Equilibrium ◽  
Work Conditions ◽  
Bridge Pier ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Analysis Method ◽  
Equilibrium Equations ◽  
Different Types ◽  
Ice Loads

In order to discuss the effect of earthquake and dynamic ice loads to a bridge pier, this paper considered the effect of added mass of dynamic water, and it deduced the dynamic equilibrium equations for a bridge pier subject to earthquake and dynamic ice loads on the basis of nonlinear Morision equation. Using numerical analysis method, it discussed the dynamic response of a bridge pier subject to different types of earthquake loads, forced ice loads, and both earthquake and forced ice loads. Through comparing the pier responses in different work conditions, it discovered that the dynamic responses of the bridge pier subject to forced dynamic ice loads rise and fall severely at the time of ice buckling broken periodic change. The coupling effects of forced dynamic ice loads and earthquake especially near-fault earthquake enhance the dynamic response of bridge pier significantly.

Modelling the Dynamic Response of Iced Transmission Lines Subjected to Cable Rupture and Ice Shedding

2013 ◽  
Vol 28 (2) ◽  
pp. 948-954 ◽  
Author(s):  
Farshad Mirshafiei ◽  
Ghyslaine McClure ◽  
Masoud Farzaneh
Keyword(s):  
Dynamic Response ◽  
Transmission Lines ◽  
Ice Shedding

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
Keyword(s):  
Dynamic Response ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Dynamic Strain ◽  
Power Transmission Lines ◽  
Transmission Tower ◽  
Research Results ◽  
Experiential Research ◽  
First Time

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.

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.

Component identification and defect detection in transmission lines based on deep learning

2020 ◽  
pp. 1-12
Author(s):  
Xiangyu Zheng ◽  
Rong Jia ◽  
Aisikaer ◽  
Linling Gong ◽  
Guangru Zhang ◽  
...  
Keyword(s):  
Deep Learning ◽  
Transmission Line ◽  
Defect Detection ◽  
Transmission Lines ◽  
Power Grid ◽  
Recognition Rate ◽  
Experimental Results ◽  
Component Identification ◽  
Special Power ◽  
Component Failures

Ensuring the stable and safe operation of the power system is an important work of the national power grid companies. The power grid company has established a special power inspection department to troubleshoot transmission line components and replace faulty components in a timely manner. At present, assisted manual inspection by drone inspection has become a trend of power line inspection. Automatically identifying component failures from images of UAV aerial transmission lines is a cutting-edge cross-cutting issue. Based on the above problems, the purpose of this article is to study the component identification and defect detection of transmission lines based on deep learning. This paper expands the dataset by adjusting the size of the convolution kernel of the CNN model and the rotation transformation of the image. The experimental results show that both methods can effectively improve the effectiveness and reliability of component identification and defect detection in transmission line inspection. The recognition and classification experiments were performed using the images collected by the drone. The experimental results show that the effectiveness and reliability of the deep learning method in the identification and defect detection of high-voltage transmission line components are very high. Faster R-CNN performs component identification and defect detection. The detection can reach a recognition speed of nearly 0.17 s per sheet, the recognition rate of the pressure-equalizing ring can reach 96.8%, and the mAP can reach 93.72%.

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 Modeling and Analysis of Sub-Millimeter-Wave Graphene Switches for On-Wafer Coplanar Transmission Lines

2020 ◽  
Author(s):  
Panagiotis Theofanopoulos ◽  
Georgios Trichopoulos
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Characteristic Impedance ◽  
Design Parameters ◽  
Coplanar Waveguides ◽  
Modeling And Analysis ◽  
Switching Performance ◽  
Line Characteristic ◽  
Depth Study ◽  
Impedance Scaling

We present an analysis of graphene loaded transmission line switches. Namely, we propose equivalent circuit models for graphene loaded coplanar waveguides and striplines and examine the switching performance under certain design parameters. As such, the models account for the distributed effects of electrically-large shunt switches in coplanar waveguides and we use the Babinet’s principle to derive the respective models for the coplanar stripline transmission lines. Using these models, we identify the optimum design of graphene switches based on transmission line characteristic impedance, scaling factor, graphene shape, and topology (series or shunt). We vary these parameters and obtain the insertion loss and ON/OFF ratio. Τhe extracted results can act as the design roadmap toward an optimum switch topology and emphasize the limitations with respect to fabrication challenges, parasitic effects, and radiation losses. In our models, we use measured graphene values (sheet impedance) instead of theoretical equations, to obtain the actual switching performance. Finally, the proposed equivalent models are crucial for this in-depth study; since, we simulated more than 2,000,000 configurations, a computationally challenging task with the use of full-wave solvers

Dynamic Response of Composite Two-Dimensional Elasticity Problems Solved by DQEM and EDQ Based Time Integration Method

2004 ◽  
Author(s):  
Chang-New Chen
Keyword(s):  
Dynamic Response ◽  
Dynamic Equilibrium ◽  
Time Integration ◽  
Element Model ◽  
Equation System ◽  
Two Dimensional ◽  
Equilibrium Equations ◽  
Integration Schemes ◽  
Time Element ◽  
Elasticity Problems

The dynamic response of composite two-dimensional elasticity problems is solved by using the DQEM to the spacial discretization and EDQ to the temporal discretization. In the DQEM discretization, DQ is used to define the discrete element model. Discrete dynamic equilibrium equations defined at interior nodes in all elements, transition conditions defined on the inter-element boundary of two adjacent elements and boundary conditions at the structural boundary form a dynamic equation system at a specified time stage. The dynamic equilibrium equation system can be solved by the direct time integration schemes of time-element by time-element method and stages by stages method which are developed by using EDQ and DQ. Numerical procedures and numerical results are presented.

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