Transmission Tower Research Articles

Research on Electromagnetic Scattering Influence of Transmission Towers on Medium Wave Antenna Based on the Characteristic Mode Theory

Electromagnetic scattering from UHV transmission towers is a major factor affecting the safety and stability of the surrounding antenna signal system. In this paper, the electromagnetic scattering effect of ±800 kV UHV DC transmission tower on the medium-wave antenna is investigated based on the characteristic mode theory (CMT). The simulation model of the tower and antenna is established, and the mode selection is carried out according to the percentage of the contribution of the characteristic mode to the total electromagnetic scattering. The effects of electromagnetic scattering under three conditions, namely, the number of towers, the distance between towers and antennas, and different frequencies, are investigated separately. The simulation results show that as the number of towers increases from 1 to 3, it leads to an increase in the electromagnetic scattering impact by about 49.5%. The shape distortion of the antenna’s directional map becomes more pronounced and is accompanied by the extension with the direction of the power line. The distance between the tower and the antenna is shortened from 500 m to 125 m, resulting in the growth of the influence of electromagnetic scattering by about 36.4%, and the directional gain of the antenna increases along the direction of the transmission line. As the frequency increases from 600 kHz to 1400 kHz, it leads to the rise of electromagnetic scattering effect of about 32.7% and the antenna directional map becomes more complicated. The research results will provide technical support for developing protective measures against electromagnetic scattering from UHV DC transmission towers to medium-wave antennas.

A Low Cost Real-Time Transient Recorder for High Voltage Systems.

Large-scale incorporation of new energy generation units based on renewable sources, such as wind and photovoltaic power, drastically alters the structure of the power system. Because of the intermittent nature of these sources, switching in grids (connection and disconnection) occurs much more frequently than with conventional sources. As a result, the power system will inevitably experience a large number of transients, which raises questions about the stability of the system and the quality of the electrical energy. Therefore, measuring various types of transients in power system is crucial for stability, power quality, fault analysis, protection design, and insulation design. Transient recorders that are currently used are generally expensive and only suitable for particular locations in power systems. The number of installed transient recorders is insufficient for a comprehensive analysis of problems that may occur. Hence, it is important to have inexpensive and efficient transient recorders that can be installed at multiple points in the power system on various types of objects. It is also essential to have a transient record database with open access, which can be used by researchers to develop new analysis techniques based on artificial intelligence. This paper proposes an inexpensive measurement and acquisition system designed to record transient phenomena on different objects within the power system. The system is designed to use autonomous power, a standardized data acquisition module, a low-budget system for transmitting recorded transient events to the server via mobile network, and a sensor system adapted to the object where transients are recorded. The proposed system is designed to be used for all types of objects in the power system where transients may occur, such as power lines, transmission towers, surge arresters, and transformers. All components of the system are described, and the system is tested under laboratory conditions. The modular nature of the system allows customization to the specifics of the location in power system by choosing appropriate components. The calibration method of the custom designed Rogowski coil is described. The cost analysis of the proposed system and power consumption analysis are performed. The results show that the system's performance meets application requirements at a low cost.

Research on percussion-based bolt looseness monitoring under noise interference and insufficient samples

Loose bolts are the key cause of tower collapse. The maintenance of bolts in transmission towers remains at the stage of individual inspection, and it is urgent to develop practical bolt looseness monitoring methods for engineering applications. The percussion-based method has shown its full potential due to not relying on fixed signal generators and sensors. However, its performance can severely degrade under noise interference and data scarcity. To address this problem, the new voiceprint feature that resist noise interference and classifier that alleviate sample shortages are proposed in this study, namely all-pole group delay function (APGDF) and prototypical networks. The proposed new bolt torque monitoring method is composed of the two. Under the condition that each bolt torque has only 50 percussion sound samples and −6dB signal-to-noise ratio (SNR), the accuracy of the proposed method for single bolt looseness monitoring is 77.87 %, and the accuracy of multi-bolt looseness monitoring is 80.60 %, which is significantly better than existing feature-based methods. In addition, the monitoring of bolt looseness with highly few samples and the data dimensionality reduction analysis are carried out to demonstrate the superiority of this method. The percussion point needs to be close to the loose bolt to achieve the best monitoring effect, and the percussion intensity does not affect the monitoring effect. The proposed method is expected to become the fundamental mode of bolt looseness monitoring in engineering practice.

Numerical Simulation of Impact Effect on Stability of Transmission Tower Foundation

The impact effect can cause structural damage to a transmission tower’s foundation and affect its overall stability. In order to study the influence of the impact effect on the stability of transmission tower foundations, a three-dimensional finite element numerical simulation method was used to investigate the variations in the extent of damage, displacement, and inclination degree of a transmission tower foundation under different impact velocities, impact durations, impactor shapes, and impact locations. The results show that as the impact velocity increases, the damage value of the transmission tower foundation continuously increases, and the damaged area expands. The lateral displacement value increases continuously with the duration of the impact effect, and the variation in lateral displacement follows a linear function distribution. The inclination degree of the transmission tower foundation increases continuously with increased impact duration and can lead to overturning failure. A smaller impact contact area results in a larger compressive damage value for the transmission tower foundation, and different impact contact areas lead to different modes of failure for the transmission tower foundation. The damage value and damaged area of the transmission tower foundation vary with the location of the impact. By comparing the deformation of the transmission tower foundation before and after reinforcement, it is evident that the reinforcement design can significantly improve the deformation resistance and anti-overturning capacity of the transmission tower foundation.

Transmission Tower category Identification from Airborne LiDAR Point Clouds based on Shape Curve

Using airborne LiDAR point cloud data to reconstruct the three-dimensional (3D) models of the transmission towers is crucial for ensuring power transmission safety. To enhance the models’ accuracy, knowing the tower categories is essential. However, there are few studies on the identification of tower categories at present. The existing studies have various shortcomings. Aiming at the problem of tower category identification in the application of airborne LiDAR point clouds in a smart grid, a transmission tower category identification method based on the shape curve is proposed. Firstly, a tower curve database is established based on relevant standards. Then, we employ three methods, namely dynamic time warping (DTW) distance, Hausdorff distance, and DTW-Hausdorff distance, to calculate the similarity indexes between the tower point cloud shape curves and those in the database. These indexes are used to determine the tower category. Finally, this method is tested using point clouds from transmission corridors. The experimental results show that the tower identification accuracy of DTW-Hausdorff distance is 94.0%. The tower category identification accuracy can reach 88.0%. The F-score used as the overall evaluation index of the tower identification effect is 90.9%. When employed as a similarity index, the tower identification effect is the best.

Corner guided instance segmentation network for power lines and transmission towers detection

Corner guided instance segmentation network for power lines and transmission towers detection

Study on the influence of the transmission tower on the AC interference distribution on the surface of a buried steel pipeline under steady-state conditions

Study on the influence of the transmission tower on the AC interference distribution on the surface of a buried steel pipeline under steady-state conditions

Bayesian Operational Modal Analysis with Interactive Optimization for Model Updating of Large-Size UHV Transmission Towers

Bayesian Operational Modal Analysis with Interactive Optimization for Model Updating of Large-Size UHV Transmission Towers

Bio-effects of 5th generation electromagnetic waves on organs of human beings

ObjectivesThe uses of devices of electromagnetic waves (EMWs) are increasing day by day. Similarly, the generation of the waves is increasing. The frequency spectrum of the generation of waves is also increased. In this manuscript, an analysis of the high frequency EMWs has been made by the electric fields generated due to the exposure of 5th generation (5 G) of mobile phones. MethodsDue to the emission of waves from the towers, the electric field is generated around the transmission tower of mobile phones. The electric fields are computed by the power of the transmission tower. The electric fields across the biological tissues/cells are also computed when the EMWs penetrate inside the body. The electric fields are made across the organs of different depths inside the body. ResultsThe induced electric fields inside the organs of the human beings are responsible for the absorption of energy from high frequency EMWs. The absorbed amount of energy from high frequency waves may become the cause of harmful effects on the life of organs of human beings. ConclusionIn this manuscript, after analysis of the computed electric fields inside the organs of human beings, it is concluded that the EMWs of 5 G spectrum of mobile phone towers may more harmful for the life of organs as 4th generation (4 G) spectrum of mobile phone waves. The energy absorption by the 4 G spectrum is lower than 5 G spectrum due to the range of frequency of waves. The effects on the pancreas, retina, skin, intestine, spleen, stomach and uterus are more than low water content organs like nails, bone, teeth etc.

Research on Climbing Robot for Transmission Tower Based on Foot-End Force Balancing Algorithm

This paper aims to introduce robot technology to carry out the safety inspection of transmission towers in long-distance power transmission, so as to improve the safety and efficiency of inspection. However, aiming at the problem that the existing climbing robots are mainly used for large load applications, which leads to the large size and lack of flexibility of the robot, we propose an innovative solution. Firstly, a lightweight quadruped climbing robot is designed to improve portability and operational flexibility. Then, a one-dimensional force sensor is added at the end of each leg of the robot, and a special swing phase trajectory is designed. The robot can judge whether the electromagnetic adsorption is effective and avoid potential safety hazards. Finally, based on the principle of virtual model control (VMC), a foot-end force balancing algorithm is proposed to achieve uniform distribution and continuous change in force, and improve safety and load capacity. The experiments show that the scheme has a stable climbing ability in the environments of angle steel, vertical ferromagnetic plane and transmission tower.

Stochastic stress response and dynamic reliability evaluation for transmission towers with semi-rigid behaviors

As a kind of typical wind-sensitive structure, transmission towers have attracted fast-growing attention in the field of their wind-induced dynamic response. Nevertheless, their dynamic response considering effects of semi-rigid connected joints and semi-rigid-constrained stability behaviors has not been investigated. To this end, based on the experimental and numerical study, this paper proposes a fitting formula for the stability coefficient of steel tube members with semi-rigid behaviors in transmission towers to determine the dynamic stress response. Then, the stiffness, mass, and damping matrices of steel-tube transmission towers (STTTs) with semi-rigid behaviors are determined to construct their stochastic dynamic finite element model. Subsequently, the integral form of the generalized density evolution equation is solved via a family of Dirac's sequences to conduct the stochastic stress response analysis for STTTs considering effects of semi-rigid connected joints and semi-rigid-constrained stability behaviors, and their dynamic reliability is evaluated by further introducing the extreme-value distribution method. Finally, an engineering example of an existing STTT is given, and the results indicate that the semi-rigid connected joints and semi-rigid-constrained stability behaviors would significantly affect the stochastic stress response and dynamic reliability of STTTs. Accordingly, taking into account semi-rigid connected joints and semi-rigid-constrained stability behaviors may be more applicable for analysis and design of STTTs.

Parallel Bayesian probabilistic integration for structural reliability analysis with small failure probabilities

Bayesian active learning methods have emerged for structural reliability analysis and shown more attractive features than existing active learning methods. However, it remains a challenge to actively learn the failure probability by fully exploiting its posterior statistics. In this study, a novel Bayesian active learning method termed ‘Parallel Bayesian Probabilistic Integration’ (PBPI) is proposed for structural reliability analysis, especially when involving small failure probabilities. A pseudo posterior variance of the failure probability is first heuristically proposed for providing a pragmatic uncertainty measure over the failure probability. The variance amplified importance sampling is modified in a sequential manner to allow the estimations of posterior mean and pseudo posterior variance with a large sample population. A learning function derived from the pseudo posterior variance and a stopping criterion associated with the pseudo posterior coefficient of variance of the failure probability are then presented to enable active learning. In addition, a new adaptive multi-point selection method is developed to identify multiple sample points at each iteration without the need to predefine the number, thereby allowing parallel computing. The effectiveness of the proposed PBPI method is verified by investigating four numerical examples, including a turbine blade structural model and a transmission tower structure. Results indicate that the proposed method is capable of estimating small failure probabilities with superior accuracy and efficiency over several other existing active learning reliability methods.

The performance and mechanism of abrasion damage of steel structure coatings under the action of wind gravel flow: Laboratory experiment and numerical simulation

In the Xinjiang region of China, transmission tower coatings undergo consistent wear from wind gravel flow (WGF), which jeopardizes their durability. This study assesses the effect of wind speed, attack angle, and gravel size on the durability and wear patterns of graphite/epoxy coatings by experiment and simulation. The results show that these coatings exhibit characteristics that bridge the gap between elasticity and plasticity, and larger gravel particles cause more damage than their smaller counterparts. From our experiments, a graphite/epoxy coatings abrasion model was formulated. Additionally, numerical simulations provided insights into the pressure variations on the abrasion surface and the dynamics of the neighboring flow field. This study provides guidance for the protection of electrical systems in the Gobi's windy areas.

Method for extracting the free vibration response of transmission tower

The analysis of the free vibration in transmission towers is aimed at better evaluating their health status. Due to the non-stationarity of the height of non-uniform wind-induced vibration, there is a sustained forced vibration response in the vibration signal of transmission towers. This will lead to a decrease in the stability of vibration characteristics, which brings great difficulty to transmission tower status identification. In order to solve this problem, this paper proposes a method for extracting the free vibration response of transmission towers. By using Void–Kalman filtering (VKF) and generalized demodulation transform (GDT) for modal frequency tracking and pseudo-peak elimination, the signal is maximally cleaned while retaining all modal information. In addition, this paper combines variational theory and time-frequency domain features to decompose all effective modal orders in the vibration response. This not only solves the errors that exist when GDT and VKF directly process the original signal, but also makes the extraction of frequency parameters of each modal orders more convenient. The effectiveness of this approach is demonstrated by extracting the free vibration response of a 110 kV cat-head type tower. And by comparing it with existing mainstream signal processing methods using the example of bolt loosening faults. The results show that the signal processed by this approach can more stably and accurately capture the fault characteristics, providing a new idea for the extraction of free vibration response in the field of transmission tower health monitoring.

Development of Physics-Based Virtual Training Simulator for Inspections of Steel Transmission Towers

Development of Physics-Based Virtual Training Simulator for Inspections of Steel Transmission Towers

Component Assessment of the Electric Transmission Grid to Hurricanes

AbstractThe increased frequency and intensity of extreme weather events from climate change necessitates understanding impacts on critical infrastructure, particularly electrical transmission grids. One of the foundational concepts of a grid's resilience is its robustness to extreme weather events, such as hurricanes. Resilience of the electric grid to high wind speeds is predicated upon the location and physical characteristics of the system components. Previous modeling assessments of electric grid failure were done at the systems level with assumptions on location and type of specific components. To facilitate more explicit adaptation metrics, accurate component‐level information is needed. In this study, we build and utilize a data set of location, physical characteristics, and age of transmission structures for nine counties in the Florida Panhandle. These component characteristics were then simulated for failure under a variety of scenarios using fragility curves. Eight hurricanes were modeled using Hazus from the Federal Emergency Management Administration and the resulting impact to the network was assessed. The network was generated using the transmission lines and towers, showing increasing impacts to network efficiency with larger storms. Although modern transmission structures are built under the more stringent extreme wind loading construction standards, the prevalence of older, wooden transmission structures throughout the region poses a substantial risk to reliable electricity transmission during tropical cyclone events from the Gulf of Mexico.

Research on Vibration Analysis and Online Monitoring Technology of Transmission Tower Near Railway

Research on Vibration Analysis and Online Monitoring Technology of Transmission Tower Near Railway

Probabilistic Evaluation of the Uplift Capacity of Transmission Tower Foundations Using Reinforced Anchors

Probabilistic Evaluation of the Uplift Capacity of Transmission Tower Foundations Using Reinforced Anchors

Wind Field Digital Twins Sandbox System for Transmission Towers.

Given the digitalization trends within the field of engineering, we propose a practical approach to engineering digitization. This method is established based on a physical sandbox model, camera equipment and simulation technology. We propose an image processing modeling method to establish high-precision continuous mathematical models of transmission towers. The calculation of the wind field is realized by using wind speed calculations, a load-wind-direction-time algorithm and the Continuum-Discontinuum Element Method (CDEM). The sensitivity analysis of displacement- and acceleration-controlled transmission tower loads under two different wind direction conditions is conducted. The results show that the digital model exhibits a proportional relationship with the physical dimensions of the transmission tower model. The error between the numerical simulation results and the experimental results falls within a reasonable range. Nodes at higher positions of the transmission tower experience significantly higher forces compared to those at lower positions, and the structural forms with larger windward projected areas yield similar simulation results. The proposed digital twin system can help monitor the performance of structural bodies and assess the disaster degree in extreme conditions. It can guide specific maintenance and repair tasks.

Analysis and Design of Transmission Tower Using STAAD Pro V8i

Analysis and Design of Transmission Tower Using STAAD Pro V8i