Design Of Transmission Towers Research Articles

Analysis and Design of Electrical Transmission Towers with Various Sections and Bracing Configurations

Abstract: This study focuses on the analysis and design of a 400kV electrical transmission tower with a height of 50 meters. The tower was modeled in STAAD.PRO using three distinct steel sections Angle, Tube, and Channel combined with various bracing configurations, including X, K, and D-bracings. The main objective of this study is to determine the most efficient and economical configuration for the design of Transmission tower. The tower is analyzed for Dead load, Live load and wind load as per the codes. The study concludes that transmission towers with angled sections and X-bracing exhibit moderate displacement, minimal reaction forces, and reduced structural weight, making them a preferred design choice. Manual calculations were performed to design the connections and footing, ensuring structural integrity. The results confirm that the tower's connection design is safe and reliable

Fire resistance behavior and failure analysis of transmission tower exposed to wildfires

This paper deals with the fire resistance behavior and failure mode of transmission towers exposed to wildfires. A nonlinear thermo-mechanical coupling model of a latticed transmission tower was established by the finite element (FE) program ANSYS, which was validated from steel members’ perspectives. Wildfire analysis was conducted to determine the key parameters, including the number of legs in fire, fire intensity, and residence time, and the temperature–time curve was further proposed for parametric analysis. It reveals that the transmission tower may collapse under serviceability state loads in the wildfire, and the final failure mode was determined by the number of tower legs in the wildfire. A higher wildfire intensity will significantly reduce the wildfire resistance time of the transmission tower. Therefore, combustible materials around transmission towers need to be regularly cleaned to reduce the intensity and residence time of wildfires, which is an effective way to prevent wildfires. Moreover, a wildfire protection layer design process was proposed based on the environment surrounding the transmission tower, which proved reliable to provide valuable insights for the fire protection design of transmission towers in areas prone to wildfires.

Design and experiment of transmission tower climbing robot inspired by inchworm

Purpose The purpose of this paper is to design a climbing robot connected by a connecting rod mechanism to achieve multi-functional tasks such as obstacles crossing and climbing of power transmission towers. Design/methodology/approach A connecting rod type gripper has been designed to achieve stable grasping of angle steel. Before grasping, use coordination between structures to achieve stable docking and grasping. By using the alternating movements of two claws and the middle climbing mechanism, the climbing and obstacle crossing of the angle steel were achieved. Findings Through a simple linkage mechanism, a climbing robot has been designed, greatly reducing the overall mass of the robot. It can also carry a load of 1 kg, and the climbing mechanism can perform stable climbing. The maximum step distance of the climbing robot is 543 mm, which can achieve the crossing of angle steel obstacles. Originality/value A transmission tower climbing mechanism was proposed by analyzing the working environment. Through the locking ability of the screw nut, stable clamping of the angle steel is achieved, and a pitch mechanism is designed to adjust the posture of the hand claw.

Analysis and Design of Transmission Tower Using STAAD Pro V8i

Analysis and Design of Transmission Tower Using STAAD Pro V8i

PDEM-based multi-component and global reliability evaluation framework for steel tubular transmission towers with semi-rigid connections

The conventional analysis and design of transmission towers usually ignore the effect of semi-rigid behaviors of bolted joints and simplify the joints as the rigid or pinned connection, which might overestimate or underestimate the structural response of transmission towers and the reliability of structural components and systems. To consider the effect of semi-rigid connections on the reliability of transmission towers in this paper, a stochastic dynamic finite element model of steel tubular transmission towers with semi-rigid connections (STTTs-SRCs) is established by deriving their stiffness matrix, where the uncertainties of dimensions, material and semi-rigid connections are considered and the wind loads are simulated as stochastic processes by the dimension-reduced probabilistic simulation approach. Then, based on the equivalent extreme-value event, the multi-component and global performance functions with stress and displacement failure modes for STTTs-SRCs are established, respectively. Further, a reliability evaluation framework for STTTs-SRCs is proposed based on the probability density evolution method (PDEM). Finally, a practical engineering transmission tower is regarded as an example to demonstrate the implementation process of the proposed reliability evaluation framework. Moreover, the reliability of steel tubular transmission towers with rigid and pinned connections is compared with that of STTTs-SRCs to investigate the effect of semi-rigid connections on the reliability of transmission towers. In general, the semi-rigid connections would mainly affect the value of the multi-component failure probability, however, it would not change the location where the maximum failure probability of components occurs. Additionally, the semi-rigid connection significantly affects the global failure probability of towers for the stress failure mode while slightly affects the global failure probability of towers for the displacement failure mode. Therefore, it may be more appropriate to consider the semi-rigid connections into the analysis and design of steel tubular transmission towers.

Design of Transmission Tower for a Sub Station of 132 KV

Abstract: In order to properly plan and design a structure, it is necessary to have not only imagination and conceptual thinking, but also a solid understanding of the science of structural engineering, as well as practical knowledge of recent design codes and regulations, all supported by ample experience, intuition, and judgment, with the goal of ensuring safety while maintaining a careful balance between economy and safety. One type of steel structure that has seen significant progress in recent years is the transmission tower, which must be constructed with great care and maintenance in order to ensure the safety and comfort of surrounding beings. While traditional methods of designing and analyzing transmission towers can be time-consuming, software such as "Spadaro V8i" can be used to expedite the process. In this research manual calculation is done by traditional method and after that modelling is done with software.

Research on Power Transmission Tower Planning Method Based on Real Terrain and Surface Feature

With the rapid development of power grid construction in China, the engineering construction conditions of overhead lines have changed. Further research is needed on the combination scheme of general design technical conditions of lines, tower planning, and design, etc., to meet the application requirements of the actual line projects in China for the general design of transmission line towers. This research adopts the pole and tower planning method that conforms to the real terrain and terrain conditions and considers the actual constraint information, such as the terrain, crossing trees, power lines, and railways, to carry out the planning and design of transmission line poles and towers.

OVERVIEW OF FACTORS AFFECTING THE ESTIMATION OF LIGHTNING SHIELDING PERFORMANCE OF OVERHEAD TRANSMISSION LINES

This paper examines the risk of lightning stroke to overhead transmission line. The estimation procedure for the lightning performance of overhead power lines is based on the selected lightning attachment model, available lightning parameter statistics, the transmission tower design and voltage levels, type of overvoltage and other characteristics. In this paper the overview of factors affecting the estimation of lightning shielding performance of overhead transmission lines was performed. Among the factors that can affect the estimation accuracy, one can list insufficiently accurate data on the ground flash density in the area of interest and lack of complete data on statistical distribution of lightning current magnitudes. The paper shows that the influence of wind on the increase in the horizontal exposed distance of the phase conductor is not also taken into account. In this research traditional electro-geometric model was used for estimation of lightning performance of 220 kV overhead power line. Results obtained suggest that swing of suspension insulator strings caused by strong winds may lead to increased risk of lightning shielding failure during thunderstorm. Calculation performed for 3 kA lightning current magnitude shows that at swing angle equal to –1 degree, the horizontal unprotected distance of phase conductor increases by 3.1%, that corresponds to 5.240 m uncovered width. When the swing angle is increased to –5 degree, the uncovered width is increased by 15.8% that corresponds to 5.885 m uncovered width. It is proposed that an increase in the risk of lightning shielding failure as a result of wind load can be accounted by applying an appropriate correction factor in expressions for calculation of shielding failure rate, shielding failure flashover rate, etc. Proposed correction factor should account frequency and strength of wind in the area of transmission line route and depend on transmission line voltage level and tower design. Further efforts should be focused on obtaining and justifying the numerical values ​​of this correction factor.

Structural Behaviour of Transmission Tower with Different Bracings under Wind Loading

Abstract: India has a sizable population that is dispersed throughout the nation, and this population's high need for energy production results in the need for a sizable transmission and distribution system. The present work for the design of transmission towers with foundations for two distinct zones, each with a different basic wind speed and kind of terrain. The requirement of the members has also been optimised. With the aid of Staad.pro and MS Excel's VBA, this present work has completed. Three distinct bracing systems were contrasted based on a number of factors, including deflection, weight, the quantity of joints, and cost. STAAD.pro has used to analyse the tower under various loading conditions, and Excel-VBA interface has used to construct the connections and base. The technological analysis and economic design of transmission line tower constructions have been the main aims of the present work. Under the specified loading conditions scenarios for both zones, the K bracing tower showed the least deflection in terms of the deflection criterion.

Study on the influence of calculation domain on the accuracy of CFD simulation of power transmission tower aerodynamic coefficient

Wind load is the control load in the design of power transmission tower. The shape coefficient of that can be obtained by CFD. Small calculation domain can affect the calculation accuracy, and large one can reduce the calculation efficiency. In this paper, the calculation domains with different sizes are designed to optimize the calculation domain size.

An Efficient Differential Evolution for Truss Sizing Optimization Using AdaBoost Classifier

Design constraints verification is the most computationally expensive task in evolutionary structural optimization due to a large number of structural analyses that must be conducted. Building a surrogate model to approximate the behavior of structures instead of the exact structural analyses is a possible solution to tackle this problem. However, most existing surrogate models have been designed based on regression techniques. This paper proposes a novel method, called CaDE, which adopts a machine learning classification technique for enhancing the performance of the Differential Evolution (DE) optimization. The proposed method is separated into two stages. During the first optimization stage, the original DE is implemented as usual, but all individuals produced in this phase are stored as inputs of the training data. Based on design constraints verification, these individuals are labeled as “safe” or “unsafe” and their labels are saved as outputs of the training data. When collecting enough data, an AdaBoost model is trained to evaluate the safety state of structures. This model is then used in the second stage to preliminarily assess new individuals, and unpromising ones are rejected without checking design constraints. This method reduces unnecessary structural analyses, thereby shortens the optimization process. Five benchmark truss sizing optimization problems are solved using the proposed method to demonstrate its effectiveness. The obtained results show that the CaDE finds good optimal designs with less structural analyses in comparison with the original DE and four other DE variants. The reduction rate of five examples ranges from 18 to over 50%. Moreover, the proposed method is applied to a real-size transmission tower design problem to exhibit its applicability in practice.

Stability of equal-leg angle section braces with torsional restraints

Cross bracing using the single leg angle sections are connected on both sides at the joints, affecting the stability capacity of the cross bracing because of the torque. The study on the stability capacity of equal-leg angle sections with the effects of torsional restraints at joints was insufficient. Additionally, there is no clear guidance from relevant design codes. In this study, an end constraint was designed to simulate the effect of torsional restraints for the angle sections. A total of 105 specimens of angle sections, divided into three kinds of pieces (A, B, C), were tested under three boundary conditions. Additionally, Finite Element Method modeling to study the effects of end constraint was parallelly conducted. Class B specimens had the worst stability. When the slenderness ratio is <120, the stability capacity of Class C specimens is larger. When the slenderness ratio is larger than 120, Class A specimens have better stability. The stability capacity of the equal-leg angle sections is positively related to the stiffness of the end constraint, when the stiffness is less than or equal to 200 kN•m/θ, the change of the stability capacity appears more dramatic, when the stiffness exceeds 200 kN•m/θ, the increase becomes slower. The effect of the slenderness ratio and the ratio of the torsional stiffness at nodes to the bending stiffness of columns were quantified through the stability capacities obtained from the experiment and FEMs to propose a modified method for effective length coefficients, which could optimize transmission tower design.

Analysis of Wind-Sand-Load-Induced Dynamic Response of Transmission Tower-Line Systems

Sandstorms are a common natural phenomenon that has the potential to cause severe disruptions to civil infrastructure. However, the effect of sandstorms on transmission tower structures has not received much attention. This paper proposes the simulation of the wind-sand loads for the analysis of transmission tower structures under sandstorm excitation by superposing the wind loads and sand particle loads. The wind load is generated based on Kaimal fluctuating wind power spectrum and the harmonic superposition method, and the sand load is constructed based on the law of conservation of momentum and sandstorm classification. A transmission tower was modeled and simulated in SAP2000 to explore the dynamic response of the tower towards wind-sand loads. A comparison of wind-induced and wind-sand-induced responses shows that the structural dynamic responses of transmission towers due to the wind-sand effect are pronounced. Particularly, the maximum longitudinal displacements and axial forces increased greatly. The results showed that the sandstorm loads for transmission towers cannot be neglected, and more attention should be paid to the structural design of transmission towers to resist such loads.

Lifetime multi-hazard fragility analysis of transmission towers under earthquake and wind considering wind-induced fatigue effect

Wind-induced fatigue damage is a predominant factor eventuating in structural performance degradation of transmission towers exposed to long-term environmental wind. Moreover, transmission towers may suffer from multiple extreme natural hazards (such as earthquake and strong wind) during their service lives. However, these phenomena have not been well accounted for in current design specifications and previous studies for transmission towers. To this end, this paper proposes a comprehensive probabilistic analysis framework for achieving the lifetime multi-hazard fragility evaluation by considering the wind-induced fatigue, which is applied in a 1000 kV steel tubular transmission tower. Firstly, based on the field wind data measured at the meteorological station of Qingdao city, China, from Jan. 1, 1971 to Dec. 31, 2020, a fatigue analysis is performed on an actual transmission tower constructed in this region to compute the annual mean fatigue damage. Secondly, a series of time-dependent uncertain numerical models of the tower are established by integrating the accumulated fatigue damage and material deterioration model, and nonlinear time history analyses are imposed on these models to examine the effect of fatigue damage on lifetime responses under combined earthquake and wind loads. Analogously, the time-dependent probabilistic multi-hazard demand models are derived via the dynamic analyses and statistical regression, and these demand models are employed to further develop the lifetime multi-hazard fragility surfaces of the tower. Finally, a fast lifetime safety assessment method, i.e. the critical safety surface, is proposed to efficiently judge the collapse state of the transmission tower at various wind speeds, PGAs and service times. Numerical results indicate that the structural capacity of the transmission tower will experience significant deterioration due to wind-induced fatigue damage; the multi-hazard induced structural responses and fragilities will considerably increase with the service life although the tower is initially well-designed. The proposed analysis framework will be beneficial for the design and maintenance of transmission towers subjected to both earthquake and wind hazards for designers and decision-makers.

Analysis and Design of Transmission Tower Using Staad Pro for Indian Condition

Abstract: The structural planning and design process includes not only creativity and logic, but also a solid understanding of structural engineering science, as well as practical knowledge of modern design codes and bye laws, as well as a wealth of experience, intuition, and judgement. The purpose of standards is to ensure and improve people's and the environment's safety. A steel structure created by striking a fine balance between cost and security. The transmission tower, in particular, must consider safety first in order to provide a comfortable environment. For the benefit of those who live nearby as a result, the transmission tower needs to be properly constructed and maintained. As a result, the transmission tower must be built and maintained with care. Normal tower design and analysis takes more time, thus we use various tools to get the findings. "STAAD Pro V8i" is used to analyze and design transmission towers. Keywords: Transmission Line Tower, Analysis, Design, STAAD Pro.

A Review on Analysis and Design of Transmission Tower

Abstract: The structural planning and design process involves not just imagination and intellectual thinking, but also a thorough understanding of structural engineering science, as well as practical knowledge of modern design codes and bye laws, as well as a wealth of experience, intuition, and judgement. The goal of standards is to ensure and improve the safety of people and the environment. Tower is a steel structure developed by maintaining a delicate balance between economics and security. The transmission tower, in particular in order to establish a comfortable environment, the first thing that must be considered is safety. For the benefit of the beings in the immediate vicinity As a result, the transmission tower must be built and maintained properly. Therefore, the transmission tower has to be constructed with a proper care and maintenance. By normal designing and analysis of the tower it requires a more time so we adopt different softwares to obtain the results. So, analysis and designing of a transmission tower is done by “STAAD.Pro V8i”. Keywords: Transmission Line Tower, Analysis, Design, Staad-pro.

Frequency Domain Analysis of Alongwind Response and Study of Wind Loads for Transmission Tower Subjected to Downbursts

Downburst is one of the high-intensity winds that cause transmission tower failures. The regulations of transmission tower-line systems under downburst wind loads cannot meet the design requirements at present. In this paper, the calculation formulas of the background and resonant components of transmission tower under downburst wind loads are obtained, based on the modal analysis theory of non-stationary wind for the single-degree-of-freedom system in the frequency domain. The effects of structural dynamic characteristics, damping ratio, and mean wind speed vertical profile on dynamic effect on structural response are discussed. Then the equivalent static wind load (ESWL) is obtained according to the maximum response and compared with the finite element method (FEM) in the time domain. Applications of these formulas are addressed to the cases from the empirical model of Holmes and field record of a rear flank downdraft (RFD). The results show that the maximum responses obtained by the current formulas match well with those from the modal decomposition method and dynamic analysis with FEM. The internal forces of tower members calculated by ESWL based on maximum response are closer to the results from FEM than those calculated by downburst loads recommended in ASCE guidelines. The presented framework can be used to assist the wind-resistant design of transmission towers considering downburst wind load.

The design of a steel lattice transmission tower in Central Europe

AbstractThe current paper resumes the design of a steel lattice transmission tower carried out in the framework of the RFCS‐funded research project ANGELHY. The scope of ANGELHY is the establishment of analysis methods for lattice towers and the development of design rules for steel and hybrid angle sections, as well as built‐up members composed of angles. In Europe, the design of transmission towers for overhead electrical lines can be carried out according to EN 1993‐3‐1: 2006 or for electrical lines exceeding 1 kV according to EN 50341‐1: 2012. Both standards prescribe linear elastic global analyses for the design of steel lattice towers. In the current paper, the linear elastic design of the suspension transmission tower according to the German National Annex of EN 50341‐1:2012 is presented. In a first step, common typologies of lattice transmission towers used in Europe are described. In a second step, the chosen tower typology is explained in detail. The Danube tower represents the widest spread tower typology in Europe. Finally, the detailed design procedure of the tower according to EN 50341‐1:2012 is presented. The design is carried out with the software TOWER – Version 15.0 from Power Line Systems.

Performance of Steel Monopole Transmission Line Supporting Structure in Various Wind Zones of India

The design of every new transmission line can address the solutions to fresh engineering problem. Therefore, the selection of the monopole structures in place of conventional lattice towers summarized the obligatory design parameters. The reliability climatic wind loads and the security longitudinal broken wire load combinations influence the internal parameter assessment of the steel pole structures. To assess them, a 60m high double circuit (DC) 220kV line with 305 m basic span is selected. All the Six wind zones (33, 39, 44, 47, 50, and 55 m/s) of India are selected to compute the transverse wind loads on the tower. Secondly broken wire security load in the longitudinal direction is adopted for the load combination for the monopole transmission tower design. With the above data, this paper presented the variation of the internal parameters in the wind zones. It is found that even though the basic wind speed from 33 m/s to 55 m/s is increased to 66.66%, top deflection is increased by 1.6%, a bending moment is enhanced by 6.3 % and shear force is increased by 12.6% only. The results show the change of wind speed has a little effect on the monopole tower. However, the variations of internal parameters in the wind zone are strongly depending on the Longitudinal loading only. The ASCE 48-19 steel monopole code is adopted to design the monopole since the Indian standard design code for monopole was not found. However, when comparing with the Indian Standard general Steel code IS 800-2007(Limit state) design guidelines, the Indian steel code contributes 10% more weight.

Literature Review on Failure Analysis Transmission Tower Design

Literature Review on Failure Analysis Transmission Tower Design