Analysis of Weak Parts of Narrow Transmission Towers and the Reinforcement Measure

2015 ◽  
Author(s):  
Weijun Yang ◽  
Xiaofang Li ◽  
Yongda Yang
Keyword(s):  
Transmission Towers ◽  
Reinforcement Measure

scholarly journals Symmetry Analysis of Oriental Polygonal Pagodas Using 3D Point Clouds for Cultural Heritage

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1228
Author(s):  
Ting On Chan ◽  
Linyuan Xia ◽  
Yimin Chen ◽  
Wei Lang ◽  
Tingting Chen ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Unmanned Aerial Vehicle ◽  
Point Cloud ◽  
Geometric Model ◽  
Digital Camera ◽  
Point Clouds ◽  
Symmetry Analysis ◽  
3D Point Clouds ◽  
Transmission Towers ◽  
Aerial Vehicle

Ancient pagodas are usually parts of hot tourist spots in many oriental countries due to their unique historical backgrounds. They are usually polygonal structures comprised by multiple floors, which are separated by eaves. In this paper, we propose a new method to investigate both the rotational and reflectional symmetry of such polygonal pagodas through developing novel geometric models to fit to the 3D point clouds obtained from photogrammetric reconstruction. The geometric model consists of multiple polygonal pyramid/prism models but has a common central axis. The method was verified by four datasets collected by an unmanned aerial vehicle (UAV) and a hand-held digital camera. The results indicate that the models fit accurately to the pagodas’ point clouds. The symmetry was realized by rotating and reflecting the pagodas’ point clouds after a complete leveling of the point cloud was achieved using the estimated central axes. The results show that there are RMSEs of 5.04 cm and 5.20 cm deviated from the perfect (theoretical) rotational and reflectional symmetries, respectively. This concludes that the examined pagodas are highly symmetric, both rotationally and reflectionally. The concept presented in the paper not only work for polygonal pagodas, but it can also be readily transformed and implemented for other applications for other pagoda-like objects such as transmission towers.

scholarly journals Effect of Earthing Enhancing Compound (EEC) on Improving Tower Footing Resistance of a 500 kV Tower in a Rocky Area

2021 ◽  
Vol 11 (12) ◽  
pp. 5623
Author(s):  
Nur Alia Farina Mohd Nasir ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Miszaina Osman ◽  
Muhamad Safwan Abd Rahman ◽  
Ungku Anisa Ungku Amirulddin ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Comparative Analysis ◽  
Transmission Line ◽  
Structure Analysis ◽  
Current Distribution ◽  
Soil Profile ◽  
Soil Structure ◽  
Soil Resistivity ◽  
Transmission Towers ◽  
Rocky Soil

This paper presents a comparative analysis of different earthing designs’ performances, with particular interest on the use of earthing enhancing compound (EEC) for a selected earthing design of 500 kV transmission towers in a rocky soil, using the SESCAD tool of the Current distribution, electromagnetic field grounding and soil structure analysis (CDEGS) software. The simulation included the interpretation of soil profile and comparison between designs A, B and C, which are currently used for the 500 kV tower footing resistance (TFR) improvement. Results showed each design had reduced the TFR by 66%, 54.7% and 63.2% for the towers T42, T48 and T50, respectively. In some cases, further improvement of TFR is required, especially in the rocky area where the soil resistivity (SR) value is of more than 500 Ω⋅m. In this case, EEC was used in Design C, encasing both the vertical and horizontal electrodes, and it reduced the TFR further by 16% to 20%. The characteristics of the soil and earthing arrangement design play an important role in achieving a low TFR value, which is directly proportional to the backflashover occurrence and thus to the transmission line performance.

Ultrasonic unilateral double-position excitation lamb wave defect detection and quantification method for ground electrode of transmission tower

2021 ◽  
pp. 1-15
Author(s):  
Kuan Ye ◽  
Kai Zhou ◽  
Ren Zhigang ◽  
Ruizhe Zhang ◽  
Chunsheng Li ◽  
...  
Keyword(s):  
Guided Waves ◽  
Power Transmission ◽  
Geometric Model ◽  
Guided Wave ◽  
Quantization Error ◽  
Dispersion Function ◽  
Stable Operation ◽  
Transmission Tower ◽  
Ultrasonic Guided Wave ◽  
Transmission Towers

The power transmission tower’s ground electrode defect will affect its normal current dispersion function and threaten the power system’s safe and stable operation and even personal safety. Aiming at the problem that the buried grounding grid is difficult to be detected, this paper proposes a method for identifying the ground electrode defects of transmission towers based on single-side multi-point excited ultrasonic guided waves. The geometric model, ultrasonic excitation model, and physical model are established, and the feasibility of ultrasonic guided wave detection is verified through the simulation and experiment. In actual inspection, it is equally important to determine the specific location of the defect. Therefore, a multi-point excitation method is proposed to determine the defect’s actual position by combining the ultrasonic guided wave signals at different excitation positions. Besides, the precise quantification of flat steel grounding electrode defects is achieved through the feature extraction-neural network method. Field test results show that, compared with the commercial double-sided excitation transducer, the single-sided excitation transducer proposed in this paper has a lower defect quantization error in defect quantification. The average quantization error is reduced by approximately 76%.

A New Reinforcement Measure Suited for Space Truss with No-Fire Operation

2014 ◽  
Vol 919-921 ◽  
pp. 401-405
Author(s):  
Zuo Yun Mei ◽  
Chuan Qing Liu ◽  
Xing Mi ◽  
Ping Wu
Keyword(s):  
Element Model ◽  
High Yield ◽  
Nonlinear Analyses ◽  
High Yield Strength ◽  
Shell Elements ◽  
Gas Stations ◽  
Space Truss ◽  
Reinforcement Measure ◽  
Space Trusses ◽  
Elastic Stage

A new reinforcement measure with no-fire operation is presented, which is very suitable for space trusses which are located in gas stations. A finite element model (FEM) is presented with shell elements and multipoint constraint elements. With this FEM, nonlinear analyses are carried out. Analytical results show that integral failure of reinforced pipe is caused by yielding of original pipe inside. So it is not necessary to reinforce original pipe using steel pipe bonded outside with high yield strength. With the increase of length of bonded pipe outside, loading according to elastic stage and ultimate bearing loading increase, it is clear that the length of bonded pipe outside is an important factor which influences the bearing capacity.

Influence Coefficient of Filler Plates in Built-Up Cruciform Section Members Formed by Two Equal-Leg Angles

2011 ◽  
Vol 243-249 ◽  
pp. 584-591
Author(s):  
Long Yu Yang ◽  
Zheng Liang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
High Voltage ◽  
Cross Sections ◽  
Radius Of Gyration ◽  
Influence Coefficient ◽  
Transmission Towers ◽  
Minimal Radius ◽  
Extra High Voltage

The built-up cruciform section formed by two equal-leg angles has been widely applied in extra high voltage(EHV) transmission towers, however, domestic codes provide structure requirement and overlook the influence of multi filler plates to members’ bearing capacity. For the purpose of this, a pin end experiment covering 3 different cross sections(Q420, L160*12, L160*14 and L160*16) and 7 different slendernesses(25~55) has been run. This experiment contains totally 21 specimens. Furthermore, large amounts of models have been analysis by finite element method whose parameters contain variety b/t, λ, filler plate intervals and forms, amount of bolts in filler plate. A recommended formula is given for evaluating the influence of filler plates. The results show: multi filler plates enhance bearing capacity slightly for members with λ less than 35, and the better interval for filler plates is 10i-40i(i is the minimal radius of gyration); filler plates do not work well when b/t of the member is extreme large or small, a propositional b/t range for this kind of member is 11-16; the amount of bolts in filler plate has tiny influence on members’ bearing capacity; the recommended formula is applicable and feasible for design.

Failure analysis of transmission towers

2009 ◽  
Vol 16 (6) ◽  
pp. 1922-1928 ◽  
Author(s):  
F. Albermani ◽  
S. Kitipornchai ◽  
R.W.K. Chan
Keyword(s):  
Failure Analysis ◽  
Transmission Towers
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