Transmission Tower Research Articles

UAV Inspection Technology Based on Lightweight Edge Computing Framework

At present, unmanned aerial vehicle (UAV) is usually used to capture the ground images for power inspections, then transmit the images to the fixed ground station for analysis. That method is not conducive to the rapid positioning of key parts or timely treatment. At the same time, the automatic sensing of power inspections mainly adopts the targets detection and classification algorithms based on deep learning, which has a large amount of calculation, and the processor installed in the UAV terminal is difficult to achieve the effect of real-time detection. In order to improve the accuracy and real-time of key targets detection and classification of power facilities in the inspection process, a lightweight edge computing framework AirNet is proposed. In AirNet, simple linear iterative clustering (SLIC) algorithm and direct convolution method are used to optimize the UAV input image to simplify multiple granularity feature information and improve the accuracy of the algorithm. Real time intelligent analysis of the algorithm model is carried out in UAV terminal, and the key parts of transmission towers, houses and vehicles are selected for test. The results show that the algorithm can achieve 64 ms detection speed and 85% accuracy on Huawei Atlas 200 chip equipment.

Classification of high-voltage power line structures in low density ALS data acquired over broad non-urban areas.

Airborne laser scanning (ALS) has gained importance over recent decades for multiple uses related to the cartography of landscapes. Processing ALS data over large areas for forest resource estimation and ecological assessments requires efficient algorithms to filter out some points from the raw data and remove human-made structures that would otherwise be mistaken for natural objects. In this paper, we describe an algorithm developed for the segmentation and cleaning of electrical network facilities in low density (2.5 to 13 points/m2) ALS point clouds. The algorithm was designed to identify transmission towers, conductor wires and earth wires from high-voltage power lines in natural landscapes. The method is based on two priors i.e. (1) the availability of a map of the high-voltage power lines across the area of interest and (2) knowledge of the type of transmission towers that hold the conductors along a given power line. It was tested on a network totalling 200 km of wires supported by 415 transmission towers with diverse topographies and topologies with an accuracy of 98.6%. This work will help further the automated detection capacity of power line structures, which had previously been limited to high density point clouds in small, urbanised areas. The method is open-source and available online.

Analysis and prediction of electromagnetic field distribution characteristics for mobile base station co-located with high voltage transmission tower

In order to understand the impact of electromagnetic radiation on power inspectors who work on a high voltage transmission tower equipped with a mobile base station, we investigate the electromagnetic field distribution characteristics of the mobile base station co-located with high voltage transmission tower. Electromagnetic field intensity measurements in the realistic scenario of 4G base station co-located with 220 kV high-voltage transmission tower are performed, and field intensity measurement data in the ground area around the tower and in the vertical direction inside the tower are acquired. Based on the ray tracing simulation and depending on experimental verification, the electromagnetic field distribution characteristics of mobile base station co-located with high-voltage transmission tower are comprehensively analyzed. According to the measurement and simulation results, a method for partitioning strong, middle and weak field intensity areas is proposed. Finally, the radial basis function neural network is applied to the field strength prediction, and a prediction model for electromagnetic field distribution characteristics is established. These results can provide a reference for the safe operation and inspection in the scenario of mobile base station co-located with high voltage transmission tower.

Severe Convective Wind Environments and Future Projected Changes in Australia

AbstractThunderstorms can produce severe convective winds (SCWs) that damage buildings and other infrastructure such as electricity transmission towers. Understanding the climatology of SCWs is therefore important for planning and risk management. An archive of observed SCWs is used to examine a diverse set of diagnostics for indicating SCW environments based on reanalysis data. These diagnostics are then applied to climate model data to examine projections of future climate change for Australia. A diagnostic based on logistic regression is found to provide a better representation of observed SCW occurrences than other diagnostics. Projections for the future based on that diagnostic indicate increases and decreases between −16% and 34% in the occurrence frequency of regionally averaged SCW environments, based on the 10th and 90th percentile estimates of annual mean changes from a 12‐member ensemble of global climate models. Projections based on other severe weather diagnostics indicate a wider range of future changes, including increases and decreases of up to 50% in magnitude, with regional and seasonal variations through Australia. Changes in the frequency of SCW environments appears to be largely driven by increased low level moisture concentrations which can lead to increased convective available potential energy, countered in some cases by a stabilization of the mid‐troposphere temperature lapse rate. These results represent the most comprehensive estimate to date for constraining the range of uncertainty in projected future changes in convective environments for Australia, including severe thunderstorms and associated SCWs, noting that this has significant implications for risk management and climate adaptation purposes.

Wind-induced response of crane structure with double flat arms for long-span transmission towers

Wind-induced response of crane structure with double flat arms for long-span transmission towers

Efficient analysis of block circulant structures

A circulant structures has a repetitive component and the entire structure can be formed through the rotation of the repetitive component about the axis of symmetry of the structure. The analysis of such structures can be simplified through the correct understanding of the circular properties. This paper introduces different types of circulant structures and determines the problem of their eigenvalues, which play a major role in engineering applications. Our study first introduces different types of circulant models that are not exclusively designed for simple domes, but rather they include many different types of structures such as power transmission towers, diamatic domes, pyramid domes, silos, etc. In circulant structures, an entire structure can be formed through rotation of the circulant component around the structural axis. A method for calculating the eigenvalues of a circulant structure is presented. In this method the circulant structural model is decomposed and the repetitive component of the structure is identified. This component, along with its connectivity with the previous and subsequent repetitive components, is modeled and the properties of the repetitive component are included in the computations. Examples are provided to show the efficiency of the circulant structural modeling and analysis, and the computational time for analysis of circulant structures is compared to those of the standard finite element program to demonstrate the efficiency of this type of modeling. The codes utilized in this study are written in MATLAB as provided in the Appendix.

A Short Review on Various Types Transmission Tower Structure and Its Design

A Short Review on Various Types Transmission Tower Structure and Its Design

Protection of electricity transmission infrastructure from sinkhole hazard based on electrical resistivity tomography

Sinkhole formation induced by limestone quarrying has the potential to cause severe environmental problems that impact agricultural activities and damage property. Moreover, sinkholes present a stability hazard to critical infrastructure such as power transmission towers. Field investigations in northeast Thailand found surface expressions of potentially dangerous sinkholes adjacent to a limestone quarry. 2D electrical resistivity tomography (ERT) profiles were deployed across previously mapped fractures that are located near power lines in order to detect the presence of subsurface structures and cavities in the carbonate bedrock. A 3D ERT survey was conducted near the base of power transmission tower T1 to precisely determine variations in subsurface material and structures. The ERT results were combined to delineate possibly hazardous cavities and continuous fractures. The surficial collapse features were generally observed to be in alignment with interpreted subsurface cavities and fractures. Water-table declines, quarry dewatering, and quarry blasting are possible triggers for the formation of the sinkholes. Additional sinkhole collapses could intensify along specific air-filled cavity zones in the near surface. Professional evaluations and regulatory action may be necessary to limit further quarry dewatering activities and prevent additional sinkhole collapses and further risk to the power infrastructure.

Corrosion analysis of angle steel used in 500kV transmission tower

Transmission tower is the load-bearing structure of high-voltage transmission line, and its stability is very important for the reliable operation of grid equipment. In recent years, the corrosion of transmission towers has become increasingly prominent due to long-term service in the harsh field, which seriously affects its service life. In this paper, the corroded angle steel of high-voltage power tower was studied by different physical and chemical testing methods such as macro inspection, metallographic analysis, mechanical property test, chemical composition analysis, energy spectrum analysisand scanning electron micrograph analysis. The result reveled that the galvanized protective layer of the angle steel was well preserved without corrosion damage, and the corrosion spot on surface of the tower materail was caused by the corrosion of other metal parts nearby and then the rusting outcome flowed with rain water to its surface.

Discussion and analysis on corrosion causes of metallic components used in transmission tower

With the rapid development of power grid and the continuous aggravation of heavy industry pollution, more and more attention would be paid to the corrosion of metallic components of transmission line. The chemical and electrochemical corrosion of transmission tower and its fittings would shorten the service life. Therefore, it requires regular anti-corrosion coating treatment or even overall replacement, which not only wastes a lot of financial and material resources, but also causes safety accidents. In this paper, different testing methods such as macro inspection, metallographic analysis and energy spectrum analysis were adopt to investigat and analyse corrosion behaviour of cotter pin, fitting, guyed rod and angle steel used in transmission tower. Additionally, corresponding anti-corrosion measures were put forward in order to improve the anti-corrosion performance of the metallic components and guarantee the safety and stability of transmission line.

Dynamic Response of a Cat Head Type Transmission Tower-line System under Strong Wind

Transmission tower plays important role in the power system and it is security sensitive in various working conditions, such as wind and ice. In this paper, a method to obtain the dynamic response of a cat head type transmission tower under strong fluctuating wind was proposed. The coupled tower-lines finite element model was established in ABAQUS, and the equivalent acceleration of fluctuating wind was simulated by MATLAB. Then the displacements and stresses time histories were obtained. The method introduced in this paper can be used to assess the safety of tower under different fluctuating wind with different directions and provide a reference of the tower in the design stage.

Numerical Modelling Of Glass Fibre Reinforced Polymer (Gfrp) Tube Subjected To Torsion

Glass Fibre Reinforced Polymer (GFRP) tubes have been used widely as cross arm of electric transmission towers to replaced old wooden cross arms. Cross arm is a part of transmission tower which is required to support conductors or electrical cables. Due to nature of assembly of these GFRP tubes, it will induce torsional force to the individual GFRP tubes of cross arm. The importance of torsional effect to the cross arm has encouraged researcher to study on torsional strength of the single tube itself in order to support a complete set cross arm. In this paper, the performance of glass fiber-reinforced polymer (GFRP) tubes under statically torsional loads was studied numerically. The specimens’ ultimate twisting angle and strain were studied through tests for validation of the numerical model. Explicit solver of ANSYS was chosen and simulation results matched experiment results well with 4 % different. There are six model were simulated and analyzed in this research. It is concluded that model 4 shown the highest ultimate strains as well as twisting angle while model 3 has the lowest ultimate strains and twisting angle. The presence of fiber orientation of 90o in model 4 has contributed to the torsional capacity of the tubes.

Influence Depth of the Tensile Capacity of Ground Anchors Folding Type in Cohesive Soils

A ground anchor is used to withstand tensile stresses caused by loading both the natural load of the soil and external pressures, then passing the force into the ground. It is generally used to retain tensile form and lateral power structures in constructing walls, foundations, transmission towers, pile, floating docks, mooring dolphin, and offshore buildings. Various ground anchors have been widely used, such as drag, helical, circular-shaped plates, and squares. Especially for massive plate anchors, installation is complicated because it must be excavated first before installation. A challenge in engineering is especially on cohesive soil conditions (soft soil). With these considerations, it is necessary to develop innovative models that are easier to install but still have a large enough tensile capacity. This research analyzes the tensile capacity by using ground anchor folding type to overcome building problems on cohesive soil. The test was tensile capacity with four leaves and a Variation of depth-the performance of this folding type anchor based on the tensile capacity and the anchor. The results obtained in this study; the greater area of the element occurred a significant increase in tensile capacity.

Design of autonomous navigation system for electric patrol Unmanned Aerial Vehicle Based on Beidou Positioning and satellite based enhancement

In order to reduce the deviation of automatic inspection of transmission tower UAV and improve the efficiency of inspection work, the design of autonomous navigation system of electric power inspection UAV Based on Beidou Positioning and satellite based enhancement is proposed. On the basis of Beidou Positioning and satellite based enhancement, the automatic inspection projector and automatic inspection navigator of transmission tower UAV are designed, and the hardware design of the system is completed. This paper analyzes the endurance of UAV, calculates the coordinates of the best shooting point of UAV, and completes the planning of automatic inspection path of transmission tower UAV according to the horizontal offset coordinates of UAV in the process of transmission tower inspection. Combined with the automatic inspection algorithm of transmission tower UAV, the system software design is completed to realize the automatic inspection of transmission tower UAV. The simulation results show that compared with the traditional inspection system, the deviation of the designed UAV automatic inspection system for transmission tower is significantly reduced.

Intelligent Bird’s Nest Hazard Detection of Transmission Line based on RetinaNet Model

Electric energy is a kind of secondary energy with clean and efficient, convenient and safe use and the most wide range of applications. The transmission line equipment and the bird's nest on the tower will adversely affect the transmission line equipment, and even endanger the reliable operation of the transmission line. At present, the traditional manual line patrol has the problems of heavy workload, high cost, low efficiency and many blind areas, and the classical machine learning algorithm for bird nest recognition and classification is relatively low in efficiency and accuracy. In order to solve this problem, the RetinaNet model based on deep convolution neural network is selected for automatic detection of bird's nest targets. By adjusting the appropriate network structure and parameters to optimize the model, a RetinaNet model suitable for bird nest detection is established. The experimental results show that the accuracy of RetinaNet is 94.1%, and the recognition speed of each image is 68ms. Compared with Faster R-CNN, YOLO and SSD methods, the validity and reliability of RetinaNet model for bird's nest detection on transmission line equipment and towers are verified.

Dynamic response of hollow sandwich cement rod of 110 Kv transmission line

Taking a 110 kV transmission line as the research object, a refined finite element model of three pole two line transmission tower line system is established.Considering collision and contact between a dropped wire and ground, nonlinear dynamic analyses of the system with different break points and different numbers of broken wires were performed. The results showed that the break point location has little effects on the impact action of broken wire; the tension decay coefficient of the broken wire decreases with increase in the height of the hanging point position, while that of the unbroken wire decreases first and then increases with increase in the height of the hanging point position. The initial pretension, wind direction angle and span of the cable are selected for parameter analysis. The influence of these parameters on the nonlinear dynamic stability critical load of the hollow mezzanine concrete pole line system is investigated.

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.

Causes of Failure and Strengthening Measures of a Pile Foundation Supporting Transmission Line Tower

The present paper describes the failure of an under-reamed pile foundation supporting a transmission line tower. Assessment of in-service pile conditions, i.e., in-built length, depth of bulb, uniformity of cross-sectional area, and length of the pile, are estimated through low strain integrity test. Integrity test results reveal that improper bulb formation and shorter as-built length than the designed are the leading causes of failure. Different performance criteria (uplift, compressive, and lateral capacities) of the in-service pile foundation are estimated through extensive finite element analysis and conventional approaches. Different geometric characteristics, i.e., straight shaft, different diameter of the bulb, and pile length, are simulated to represent the in-service pile conditions in the field. The estimated performance criteria are compared with the initial design values to evaluate the required degree of strengthening measures. The paper presents the initial design criteria of pile, soil condition, low strain integrity test, finite element modeling, and strengthening measures of the pile foundation to ensure the long-term stability of the transmission tower.

Vortex-Induced Vibration and Countermeasure of a Tubular Transmission Tower

Transmission towers with steel tubes or so-called tubular towers are widely used for ultra-high voltage (UHV) transmission because of their overall higher strength and stability, and better wind resistant capability. However, within a specific wind velocity range, tubular members with a high slenderness ratio are susceptible to joint fatigue failure under the vortex-induced vibration (VIV). To thoroughly unveil the mechanism of VIV of tubular members in UHV transmission towers, this paper first measures the acceleration and corresponding wind velocity of a tubular member under the VIV, followed by an identification of the first-order frequency. Then, a simulation framework for the tubular members subjected to the VIV is proposed. The system considered is simplified as a mass–spring–damping system with the non-linear coupling effect between the tubular member and wind field taken into account. Based on the analysis, the lock-in region and maximum displacement amplitudes in the cross-wind direction are calculated, while the simulation accuracy is verified via comparison with the on-site measured data. Meanwhile, the influence of damping ratio on the VIV is studied. Finally, a new type of radial spoiler is proposed to suppress the VIV of the tubular members. The results of the 3D simulation show that the proposed radial spoiler can effectively suppress the vortex generation, and there is no noticeable vibration after the installation of the countermeasure. In effect, it was demonstrated that the proposed countermeasure can effectively suppress the VIV of the tubular tower. The parametric analysis reveals that the distance between two adjacent spoilers has a significant impact on the control efficiency and should be carefully designed for each project.

Wind tunnel tests and dynamic analysis of wind-induced response of a transmission tower on a hill

A hill with a lattice transmission tower presents complex wind field characteristics. The commonly used computational fluid dynamics (CFD) simulations are difficult to analyze the wind resistance and dynamic responses of the transmission tower due to structural complexity. In this study, wind tunnel tests and numerical simulations are conducted to analyze the wind field of the hill and the dynamic responses of the transmission tower built on it. The hill models with different slopes are investigated by wind tunnel tests to measure the wind field characteristics, such as mean speed and turbulence intensity. The study shows that the existence of a transmission tower reduces the wind speed on the leeward slope significantly but has little effect on the windward slope. To study the dynamic behavior of the transmission tower, a hybrid analysis procedure is used by introducing the measured experimental wind information to the finite element tower model established using ANSYS. The effects of hill slope on the maximum displacement response of the tower are studied. The results show that the maximum value of the response is the largest when the hill slope is 25° compared to those when hill slope is 15° and 35°. The results extend the knowledge concerning wind tunnel tests on hills of different terrain and provide a comprehensive understanding of the interactive effects between the hill and existing transmission tower regarding to the wind field characteristics and structural dynamic responses.