High Voltage Transmission Tower Research Articles

Numerical Analysis of the Influence of Tunnel Construction on High-Voltage Transmission Tower

Coal mining often results in settlement of tower foundation and stress change of tower. The influence of tunnel construction on above tower is similar to the influence of coal mining on above tower. Therefore, it is necessary to analyze the settlement of tower foundation and stress of tower. Some reinforcement measures have been taken to the foundation of tower before tunnel construction. The settlement of tower foundation and stress of tower is analyzed by ABAQUS finite element software. The analyses show that the settlement of tower foundation and stress of tower are within the range of the allowable, during tunnel construction. These show that the safety of the tower can be guaranteed after reinforcement.

Numerical Simulation Analysis of High-Voltage Transmission Tower

With the rapid development of Chinese economy construction, hv transmission line has become the main channel for long-distance power transmission and also the most basic conveyance systems and infrastructure for industrial and mining enterprises. The major coal mine fields in China have hv transmission lines passing above. Coal mining subsidence has an important influence on the line tower. So it is important to study the High-voltage transmission line tower to ensure its safety. In this paper, the model is a High-voltage transmission tower. The mechanical analyses for the tower under different boundary conditions are made by finite element simulation. The results can be used as reference for the design of high-voltage transmission line tower in mining area.

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

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.

An invisible height evaluation system for building height regulation to preserve good landscapes using augmented reality

Preserving good landscapes such as historical buildings, temples, shrines, churches, bridges, and natural sceneries is important. Recently, destruction of good landscapes from multiple viewpoints due to construction of high rise buildings has been reported. To regulate structures such as high rise buildings and high voltage transmission towers, the government or public agencies have established or are going to constitute height regulations for building and structures surrounding the location of interest. In order to check whether some portions of high structures are visible or not behind the locations of interest from multiple viewpoints, it is necessary to make a 3D model representing geography, existing structures and natural objects using 3D CAD or Virtual Reality (VR) software. However, it usually takes much time and cost to make such a 3D model. Thus, in this research, we propose a new method using Augmented Reality (AR). In this method, a number of 3D virtual rectangular objects with a scale are located on the grid of 3D geographical model. And then, the CG models are displayed in an overlapping manner with the actual landscape from multiple viewpoints using the AR technology. The user measures the maximum invisible height for each rectangular object at a grid point. Using the measured data, the government or public agencies can establish appropriate height regulation for all surrounding areas of the locations of interest. To verify the proposed method, we developed a system deploying ARToolKit and applied it to the Convention Center of Osaka University, deemed as a scenic building. We checked the performance of the system and evaluated the error of the obtained data. In conclusion, the proposed method was evaluated feasible and effective.

Structural topology optimization of high-voltage transmission tower with discrete variables

In order to solve the structural optimization problem of long-span transmission tower, topology combination optimization (TCO) method and layer combination optimization (LCO) method based on discrete variables are presented, respectively. An adaptive genetic algorithm (AGA) is proposed as optimization algorithm. Four methods: cross-section size optimization (CSSO) method, shape combination optimization (SCO) method, the TCO method and the LCO method, are utilized to optimize the transmission steel tower, respectively. The topology optimization rules are presented for the TCO method, and the layering optimization rules are presented for the LCO method. A high-voltage steel tower is analyzed as a numerical example to illustrate the performance of the proposed methods. The simulation results demonstrate that the calculated results of both the proposed TCO method and the LCO method are obviously better than those of the CSSO method and the SCO method.

Causes of Raptor Admissions to a Wildlife Rehabilitation Center in Tenerife (Canary Islands)

We studied the causes of raptor admissions to the only wildlife rehabilitation center on the largest island of the Canarian Archipelago (Tenerife) over ten years (1998–2007). A total of 2611 birds of prey, belonging to nine falconiform diurnal raptor and four strigiform species, were admitted. The Eurasian Kestrel (Falco tinnunculus) and the Long-eared Owl (Asio otus) were the species most commonly admitted and jointly made up 85.6% of admissions. The most frequent causes of admission to the wildlife rehabilitation center were collisions (with cars, high-voltage electric transmission towers, etc.; 42.2%), starvation (5.1%) and entanglement in glue traps intended for rodents (4.7%). Poisoning and shooting were recorded for 2.4 and 1.5% of the birds admitted, respectively. Only collisions increased during the study period. A total of 1010 birds (44.4% of the total) were released to the wild following rehabilitation. We recommend more financial support for rehabilitation centers to develop detailed analytical diagnoses and rehabilitation services.

Geoarcheological and Historical Investigations in the Comal Springs Arrea, LCRA Clear Springs Autotransformer Project, Comal County, Texas

Geoarcheological and Historical Investigations in the Comal Springs Arrea, LCRA Clear Springs Autotransformer Project, Comal County, Texas

Simplified models and experimental verification for coupled transmission tower–line system to seismic excitations

The simplified computational models of high-voltage transmission tower–line system under out-of-plane and in-plane vibrations are presented due to seismic excitations in this paper. The equations of motion are derived and the computer program is compiled to obtain the earthquake responses of the coupled system. To verify the rationality of the proposed approaches, the shaking-table experiments of the coupled system of transmission lines and their supporting towers are carried out and the results indicate that the errors of theoretical and testing results of systemic seismic responses are within the acceptable arrange in engineering area. Based on these studies, a simplified analysis method is proposed to make the seismic response calculation of coupled tower–conductor system faster and more effective.

Integral Fit Joint Technologies for Composites

Seeking to expand the varieties of joining approaches for polymer-matrix composites beyond discrete fasteners as well as adhesive and non-adhesive bonds, novel assembly joints that are integral to the design and fabrication of individual components are presented. Grouped under the title of integral fit joint technologies, prior approaches to eliminating fasteners, avoiding adhesives, or bonding components by ultrasonic or other energy-augmented methods are identified and illustrated. By building upon prior efforts to apply integral fit joints in areas such as snap fits, electronic assemblies, wooden joint structures, and plastic building blocks, potential uses of thesejoining technologies in composites can be identified and evaluated. Application of integral fit joint technologies in composites requires a fundamental understanding of the strengths and weaknesses of composite material systems, component fabrication processes, the forces acting on joints as well as methods for assembling composite components together. A composite snap joint technology developed for high voltage transmission towers serves as an example in demonstrating the potential for using integral fit joints in composite structures.

Industrial system grounding for power, static, lightning, and instrumentation, practical applications

Practically every structural steel building erected for industrial use incorporates reinforcing steel bars installed in the concrete footings. This, without any additional effort, constitutes a grounding electrode. The quantity of electrodes is directly related to the building area. When the structural steel framework is erected and interconnected, these electrodes are also interconnected in a parallel arrangement. Similarly, high-voltage metal transmission towers are installed using a metal footing base embedded in a concrete filled hole. The four tower legs are effectively in parallel and offer an adequate low ground resistance such that additional electrodes are generally not required. This brings us to the main point: the reinforced concrete footings, reinforced concrete grade beams, and other reinforced concrete structures provide, with a little work, an effective, reliable, and cost attractive system grounding vehicle.

Unsteady Aerodynamics and Vortex-Induced Aeroelastic Response of a Structural Angle Section

Wake-body interactions for a two-dimensional structural angle member during stationary and vortex induced oscillatory conditions are studied using a conventional low turbulence wind tunnel. The response of an angle section with combined plunging and torsion indicates that the oscillations occur essentially in one of the two degrees-of-freedom. The measurements of frequency and phase substantiated this observation. The plunging resonance exhibits the familiar vortex capture phenomenon where the shedding frequency is controlled by the cylinder motion over a finite wind speed range. On the other hand, the torsional vibration shows a vortex control phenomenon where the vortex shedding governs the frequency of oscillation. The vortex-induced torsional resonance was found to be severe even at moderate damping levels. The results should prove useful in structural designs such as high-voltage transmission towers, antenna masts, bridges, etc., where angle sections are often used as secondary members.

Estimating the fundamental natural frequency of towers by Dunkerley's method

The use of Dunkerley's first-order method for estimating the fundamental natural frequencies of tower structures is discussed. An asymmetric geometry may be considered, even though this leads to coupling between bending and torsion. The analysis of an asymmetric high-voltage transmission tower is considered as a practical example.

Unsteady aerodynamics and vortex induced aeroelastic instability of a structural angle section

Wake-body interactions for a two-dimensional structural angle member during stationary and vortex induced oscillatory conditions are studied using a conventional low turbulence wind tunnel. The response of an angle section with combined plunging and torsion indicates that the oscillations occur essentially in one of the two degrees of freedom. The measurements of frequency and phase substantiated this observation. The plunging resonance exhibits the familiar vortex capture phenomenon where the shedding frequency is controlled by the cylinder motion over a finite wind speed range. On the other hand, the torsional vibration shows a vortex control phenomenon where the vortex shedding governs the frequency of oscillation. The vortex induced torsional resonance was found to be severe even at moderate damping levels. The results should prove useful in structural designs such as high voltage transmission towers, antenna masts, bridges, etc. where angle sections are often used as secondary members.

Electric Transmission Tower Design

The design of electric transmission towers is a specialized branch of civil engineering requiring close cooperation with electrical engineers. The structural engineer is acquainted with procedures and practices peculiar to the design of high-voltage electric transmission towers. Considerations in establishing the tower configuration are set forth. Derivation of tower loads due to conductor, wind, ice, and dead load are described. A typical 500-kv tower is used to illustrate traditional tower design. A column curve substantiated by full-scale tower tests is presented. Several types of tower footings are illustrated and their relative merits discussed. Tower testing is discussed.