Search

Insulators are critical components of transmission lines but are prone to failures that can jeopardize the safe operation of electrical power systems. Accurate detection of insulator defects is essential for timely maintenance. With advancements in object detection algorithm and artificial intelligence, insulator defect detection has garnered significant attention. However, detection accuracy remains an issue. To address this, we propose an improved transfer learning model. Our approach incorporates the Mish activation function and a global context network module to enhance the model's performance. The improved YOLOv9 model is trained and tested using two public datasets: the insulator defect image dataset and the China power line insulator dataset. Experimental results demonstrate that our model achieves optimal detection precision and recall rates of 99.84 and 99.92%, respectively—improvements of 1.06 and 1.09% over the actual YOLOv9. Additionally, our model outperforms other algorithms, such as RTDETR and SSD, particularly in adapting to complex backgrounds and detecting small targets. [ABSTRACT FROM AUTHOR]

To enhance the safety of hybrid inspection robots (HIRs) landing on power transmission lines (PTLs) with inclination and flexibility, this research derives a coupled dynamic model for a developed flying–walking power transmission line inspection robot (FPTLIR) to analyze the dynamic behavior of the FPTLIR during the landing process. The model uses the absolute nodal coordinate formulation (ANCF) for the dynamics of the PTL and the Hunt–Crossley theory for the contact model, integrating these components with the Euler–Lagrange method. A modular simulation was conducted to evaluate the effects of different landing positions and robot masses. An experimental platform was designed to evaluate the landing performance and validate the model, which confirms the method's accuracy, with a mean relative Z-displacement error of 0.004. Simulation results indicate that Z-displacement decreases with increased landing distance, with the farthest point showing only 34.4% of the Z-displacement observed at the closest point. Conversely, roll increases, with the closest point exhibiting 3.7% of the roll at the farthest point. Both Z-displacement and roll are directly correlated with the robot's mass; the lightest robot's Z-displacement and roll are 9.2% and 12.8% of those of the heaviest robot, highlighting the safety advantage of lighter robots. This research enables precise analysis and prediction of the system's responses during the landing process, providing significant insights for safe landing and design. [ABSTRACT FROM AUTHOR]

The modes of reactive power compensation in the power supply system powered by a synchronous generator through a cascade of intermediate transformers have been studied. It is shown that the reactive component of the common complex resistance of the generator and the power transmission path can cause relatively large levels of reactive power in the system. Experiments show that this power remains in the system even after the application of transverse capacitive compensation, which is not able to provide full compensation of reactive power in a power supply system with a cascade of transformers. Under these conditions, the optimal value of the capacitance of the transverse compensation capacitor was found using the search optimization method on the computer model. The results of the study show the possibility of achieving the mode of full compensation of reactive power due to a relatively small increase in the capacity of the compensating capacitor, which provides transverse compensation. [ABSTRACT FROM AUTHOR]

As a large percentage of faults in transmission lines are single-line-to-ground (SLG) and transient in nature, the use of adaptive single-phase auto-reclosing (ASPAR) schemes is essential. In this paper, a new scheme for ASPAR is proposed to improve the stability and reliability of power transmission lines. The proposed approach distinguishes between the transient and permanent faults by using the feature of Stationary Wavelet Transform (SWT) and Gate Recurrent Unit (GRU) deep artificial neural network. Also, by utilizing another GRU network, the proposed scheme predicts the extinction time of the secondary arc (SA) one power cycle before the complete extinction. This can increase the speed of the faulty phase reclosing in the case of a transient fault. Simulation results carried out on a 400 kV power transmission line in the EMTP-RV and MATLAB software environments illustrate that the F1 score of the proposed ASPAR in classifying the faults is 99.55 %, and its average error in predicting the extinction time of the SA based on the root mean square error (RMSE) criterion is 0.0557. Also, the superiority and high-quality performance of the proposed protection scheme are demonstrated by comparing the results with several state-of-the-art methods.

As a large percentage of faults in transmission lines are single-line-to-ground (SLG) and transient in nature, the use of adaptive single-phase auto-reclosing (ASPAR) schemes is essential. In this paper, a new scheme for ASPAR is proposed to improve the stability and reliability of power transmission lines. The proposed approach distinguishes between the transient and permanent faults by using the feature of Stationary Wavelet Transform (SWT) and Gate Recurrent Unit (GRU) deep artificial neural network. Also, by utilizing another GRU network, the proposed scheme predicts the extinction time of the secondary arc (SA) one power cycle before the complete extinction. This can increase the speed of the faulty phase reclosing in the case of a transient fault. Simulation results carried out on a 400 kV power transmission line in the EMTP-RV and MATLAB software environments illustrate that the F 1 score of the proposed ASPAR in classifying the faults is 99.55 %, and its average error in predicting the extinction time of the SA based on the root mean square error (RMSE) criterion is 0.0557. Also, the superiority and high-quality performance of the proposed protection scheme are demonstrated by comparing the results with several state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Exact Sciences is the property of Master Editora and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Transient processes that occur during any damage to electrical power facilities carry information about the location and nature of the damage. Specific information carriers are not only the readings of observed currents and voltages but also the spectral components of these quantities. Attention is paid to the harmonics of the fundamental frequency. However, their information content cannot be sufficient to identify the damage. Moreover, there are modes in which they are compensated or absent altogether because of the disconnection of sources. The article focuses on spectral components of the free process, which is an integral part of the transient process that accompanies any damage. Being the natural frequencies of the observed network, the complex values of the frequencies of the spectral components are the same for all observation locations of a given object. The equations of the linear model of the object are compiled for these locations on the basis of the complex method, however, based only on the own complex frequency value. The spectral analysis procedures that isolate spectral components with their complex values of frequencies and amplitudes are considered. It is demonstrated that the mode of each individual spectral component can be divided into two parts, normal and local. The ratio of local complexes of the same complex frequency value on various sides of the line is uniquely related to the location of its damage. [ABSTRACT FROM AUTHOR]

To enhance the safety of hybrid inspection robots (HIRs) landing on power transmission lines (PTLs) with inclination and flexibility, this research derives a coupled dynamic model for a developed flying–walking power transmission line inspection robot (FPTLIR) to analyze the dynamic behavior of the FPTLIR during the landing process. The model uses the absolute nodal coordinate formulation (ANCF) for the dynamics of the PTL and the Hunt–Crossley theory for the contact model, integrating these components with the Euler–Lagrange method. A modular simulation was conducted to evaluate the effects of different landing positions and robot masses. An experimental platform was designed to evaluate the landing performance and validate the model, which confirms the method’s accuracy, with a mean relative Z-displacement error of 0.004. Simulation results indicate that Z-displacement decreases with increased landing distance, with the farthest point showing only 34.4% of the Z-displacement observed at the closest point. Conversely, roll increases, with the closest point exhibiting 3.7% of the roll at the farthest point. Both Z-displacement and roll are directly correlated with the robot’s mass; the lightest robot’s Z-displacement and roll are 9.2% and 12.8% of those of the heaviest robot, highlighting the safety advantage of lighter robots. This research enables precise analysis and prediction of the system’s responses during the landing process, providing significant insights for safe landing and design.

Soil is a component of the environment. An environmental policy should identify the sources of trace metals in the soil and their effects on people and living beings. The concentrations of 29 surface soil samples (0–25 cm) were determined using the methods EPA 3050B. The data were analyzed using simple and robust statistical analysis that allowed for determining geochemical baseline values. Principal component and correlation analyses were performed, which, together with a spatial analysis, allowed us to distinguish between geogenic and anthropogenic sources. The degree of soil contamination was evaluated using different ecological indices, and the health risks to children and adults were calculated using formulas proposed by the United States Environmental Protection Agency (USEPA). The median concentrations of the analyzed elements correspond to Al 17,666 (mg/kg), As 8.7 (mg/kg), Ba 61.4 (mg/kg), Cd 0.17 (mg/kg), Cr 11.3 (mg/kg), Cu 20.5 (mg/kg), Fe 25,953 (mg/kg), Hg 0.06 (mg/kg), Mn 499 (mg/kg), Ni 20.8 (mg/kg), Pb 15.9 (mg/kg), and Zn 60.6 (mg/kg). In the principal component analysis, four factors were identified that explain 70.3% of the variability of the elements, which, together with the correlation analysis, suggest that the origin of the elements is mainly geogenic with some possible anthropic contributions. The elements analyzed in the soil with moderate contamination correspond to As, Cd, and Pb, in addition, As is the only element that indicated a value above the limit for carcinogenic risk in children. The estimated geochemical baseline values correspond to Al 34,734 (mg/kg), As 15.3 (mg/kg), Ba 113 (mg/kg), Cd 0.41 (mg/kg), Cr 33.8 (mg/kg), Cu 42.9 (mg/kg), Fe 46,181 (mg/kg), Hg 0.12 (mg/kg), Mn 1015 (mg/kg), Ni 42.2 (mg/kg), Pb 21.6 (mg/kg), and Zn 121 (mg/kg). 89.7% of the total samples are at a low level of contamination. The carcinogenic risk due to As in children represents 3.4% of the total samples, so it is considered insignificant. [ABSTRACT FROM AUTHOR]

One of the key challenges in Multi-Spectral Automatic Diagnostic (MAD) robot design is the precise targeting of narrow-angle cameras on a specific part of the equipment. The paper shows that a low-cost MAD robot, whose navigation system is based on open-source ArduRover firmware and a pair of low-cost Ublox F9P GNSS receivers, can inspect the 8 × 4 degree ultraviolet camera bounding the targeting error within 0.5 degrees. To achieve this result, we propose a new targeting procedure that can be implemented without any modifications in ArduRover firmware and outperforms more expensive solutions based on LiDAR SLAM and UWB. This paper will be interesting to the developers of robotic systems for power equipment inspection because it proposes a simple and effective solution for MAD robots' camera targeting and provides the first quantitative analysis of the GNSS reception conditions during power equipment inspection. This analysis is based on the experimental results collected during the inspection of the overhead power transmission lines and equipment inspections on the open switchgear of different power plants. Moreover, it includes not only satellite, dilution of precision, and positioning/heading estimation accuracy but also the direct measurements of angular errors that could be achieved on operating power plants using GNSS-only camera targeting. [ABSTRACT FROM AUTHOR]

Foreign objects on power transmission lines carry a significant risk of triggering large-scale power interruptions which may have serious consequences for daily life if they are not detected and handled in time. To accurately detect foreign objects on power transmission lines, this paper proposes a TL-Yolo method based on the Yolov8 framework. Firstly, we design a full-dimensional dynamic convolution (ODConv) module as a backbone network to enhance the feature extraction capability, thus retaining richer semantic content and important visual features. Secondly, we present a feature fusion framework combining a weighted bidirectional feature pyramid network (BiFPN) and multiscale attention (MSA) module to mitigate the degradation effect of multiscale feature representation in the fusion process, and efficiently capture the high-level feature information and the core visual elements. Thirdly, we utilize a lightweight GSConv cross-stage partial network (GSCSP) to facilitate efficient cross-level feature fusion, significantly reducing the complexity and computation of the model. Finally, we employ the adaptive training sample selection (ATSS) strategy to balance the positive and negative samples, and dynamically adjust the selection process of the training samples according to the current state and performance of the model, thus effectively reducing the object misdetection and omission. The experimental results show that the average detection accuracy of the TL-Yolo method reaches 91.30%, which is 4.20% higher than that of the Yolov8 method. Meanwhile, the precision and recall metrics of our method are 4.64% and 3.53% higher than those of Yolov8. The visualization results also show the superior detection performance of the TL-Yolo algorithm in real scenes. Compared with the state-of-the-art methods, our method achieves higher accuracy and speed in the detection of foreign objects on power transmission lines. [ABSTRACT FROM AUTHOR]

Today the rate of anthropogenic transformations of the soil cover significantly exceeds the rate of its natural restoration. According to a modern digital soil map at a scale of 1 : 200,000 in the Leningrad Region anthropogenically modified subtypes of natural soils, which were formed as a result of human economic activity, predominate. The article considers anthropogenic changes in soils and soil cover of the territory of the high-voltage power line. The study area of 100×500 meters is located in the Tikhvinsky district between the settlements of Kalivets and Novaya Ust-Kapsha. The landscape of the territory belongs to the lake-glacial plain, the soil-forming rocks are lake-glacial sands and sandy loam. Natural soils that are not affected by technological works are found only in the forest, outside the clearing laid during the construction of the power line. These are Albic Podzol, Entic Podzol, Histic Albic Podzol, Histic Entic Podzol and Histic Gleysol. It was revealed that in the study area, the horizons of the original natural soils are partially or completely cut off, turbated, compacted, which led to the formation of their anthropogenically transformed subtypes: over-compacted, abraded, turbid and stratified. Sometimes soil material is exposed to the surface and moved over the study area by tens of meters. After the construction of the high-voltage line, new formations appeared in the soil cover, such as Podzol Nudispodic, buried soils and several types of non-soil formations. It is revealed that each technological operation (logging, installation of power transmission line supports, organization of places for technological operations and the creation of temporary roads) is characterized by its own special disturbances in the soil cover. Thus, after the construction of the power line, there were no natural soils with an undisturbed structure in the soil cover. In addition to the fundamental transformation of the soil cover at the site, natural vegetation was reduced, the mesorelief was partially disrupted and the microrelief was almost completely changed. All these anthropogenic transformations will affect the quality of the ecological functions of the soil cover. During the further operation of power transmission lines, such as clearing a cut-out clearing, updating fire-prevention mineralized strips, maintaining the power grid, disturbances of the soil cover will be periodically repeated, preventing the ecosystem from returning to its original state.

The long-span Cross-Rope Suspended (CRS) system is composed of a transmission line (conductor), a long-span suspension cable, and an insulator. The previously introduced long-span CRS with a Tension Insulator (CRSTI) has shown applicability in mountainous areas. However, the tension insulator divided the suspension cable into several sections, which made the construction of a long-span CRS rather difficult. This paper introduces long-span CRS with a Suspension Insulator (CRSSI), in which the suspension cable was not disconnected, and the conductor was supported by a suspension insulator connected to the suspension cable. For the purposes of assessment, the initial shape of the suspension cable with concentrated loading from the self-gravity of the suspension insulator and the conductors was studied, and practical lengths in construction could be calculated exactly. Secondly, the structural performance of CRSSI, including its dynamic properties and the loading effect of wind, was discussed by means of numerical analysis. Vibration modes of the structure were obtained by FE analysis. Finally, structural deformation under static wind loading was studied. The result of the analysis showed that the stiffness of CRSSI was lower than CRSTI. The first frequency of CRSSI was 6% smaller than CRSTI. Regarding static wind loading, additional displacement of the insulator contributed to the maximum displacement of long-span CRSSI. Apparently, the displacement of the suspension insulator increased with wind speed. Moreover, the number of spans has an insignificant influence on tension force and deformation. [ABSTRACT FROM AUTHOR]

Detecting defects in power transmission lines through unmanned aerial inspection images is crucial for evaluating the operational status of outdoor transmission equipment. This paper presents a defect recognition method called EDF-YOLOv5, which is based on the YOLOv5s, to enhance detection accuracy. Firstly, the EN-SPPFCSPC module is designed to improve the algorithm's ability to extract information, thereby enhancing the detection performance for small target defects. Secondly, the algorithm incorporates a high-level semantic feature information extraction network, DCNv3C3, which improves its ability to generalize to defects of different shapes. Lastly, a new bounding box loss function, Focal-CIoU, is introduced to enhance the contribution of high-quality samples during training. The experimental results demonstrate that the enhanced algorithm achieves a 2.3% increase in mean average precision (mAP@.5) for power transmission line defect detection, a 0.9% improvement in F1-score, and operates at a detection speed of 117 frames per second. These findings highlight the superior performance of EDF-YOLOv5 in detecting power transmission line defects. [ABSTRACT FROM AUTHOR]

During the past decades, the potential effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on human health have gained great interest all around the world. Though the International Commission on Non-Ionizing Radiation Protection recommended a 100 µT, and then a 200 µT magnetic field limit, the long-term effects of ELF-EMFs on organisms and systems need to be further investigated. It was reported that both electrotherapy and possible effects on human health could be induced under ELF-EM radiation with varied EM frequencies and fields. This present article intends to systematically review the in vivo experimental outcome and the corresponding mechanisms to shed some light on the safety considerations of ELF-EMFs. This will further advance the subsequent application of electrotherapy in human health. [ABSTRACT FROM AUTHOR]

To explore the factors affecting the arc extinction performance of the self-disengaging lightning protection device, a numerical simulation model of arc extinction process of the device based on magneto-hydrodynamic theory is established in this paper. The effect of the initial phase angle of the current and the peak airflow velocity of the device on the arc extinction performance of the device is investigated, and the validity of the model is verified by high-current arc-burning tests. The arc extinction time of the device is related to the initial phase of the current, and it decreases with the increase of the initial phase of the current in the interval of 0°~180° electrical phase. The peak airflow velocity of the device is critical to arc extinction. When the peak airflow velocity of the arc extinction is higher than 243 m/s, the arc can be extinguished in half a period and the re-ignition is suppressed. When the peak airflow velocity of the arc extinction is lower than 243 m/s, the 'arc blockage' appears at the outlet of the gas arc extinction cylinder of the device, leading to the arc re-ignition. The findings of this paper provide a theoretical basis for optimizing the arc extinction performance of air-blown lightning protection devices.

This paper presents a simple and effective method to extract the identification quantity of transient pulse waveform produced by the overhead transmission line short-circuit fault. This method employs the second-order time harmonic equation of the power frequency component to convert the fault full-wave data. After the conversion, only the identification quantity remains. This method can amplify high-frequency spectral content by the times of the square of the angular frequency, and hence improve the sensitivity of identifying fault transient. Using the identification quantity, one can clearly observe the arrival time and relative intensity of fault transient. A three-phase half wavelength transmission line of 50Hz/3000km is simulated with PSCAD to illuminate the effectiveness of this method. The effects of fault type, soil resistivity, fault resistance, power frequency fluctuation, sampling rate, transposition length, fault inception angle and white noise are analyzed. Calculated results show that this method can distinguish different fault type and can work effectively at low sampling rate down to 10kHz. This method is helpful for improving the performance of the traveling-wave based fault location method.

This paper presents a novel approach in which hyperparameter-tuned Machine Learning (ML) classifiers with Optuna is used for fault detection and classification over a power transmission line. In this paper, popular ML models Random Forest (RF), Decision Tree (DT), XGBoost (XGB), and Light Gradient Boosting Machine (LGBM) are used for fault detection and classification. This study uses a two-layer approach for fault detection and classification. An electrical utility and data simulation provided the PMU measurement and recorded data from a simulated grid. The faults had varied impedances and included various fault classes at distinct line locations. The optimal feature from 3-phase current and voltage signals is extracted using Pearson correlation, recursive feature elimination, and univariate feature (t-test) methods. The synthetic minority class oversampling technique (SMOTE) was used to address the issue of imbalanced data. Hyperparameters of the evaluated LGBM classifier is trained with the Optuna. The performance of the proposed classifier is measured in terms of the accuracy, precision, Recall and F1-score metrics. The proposed method outperformed the conventional ML methods.

Aiming at the problems of large error and low efficiency of transmission line icing prediction, a prediction model based on optimized SVRM is proposed. Firstly, principal component analysis (PCA) is used to extract the main features affecting line icing. Secondly, particle swarm optimization (PSO) is used to iteratively optimize the main parameters of support vector regression machine (SVRM), and the icing prediction model is established at the same time. Finally, combined with the 2 234 sets of field icing data set collected by the automatic monitoring system of an ice observation station of Sichuan Electric Power Exploration and Design Institute, the effectiveness of the prediction model is verified. Compared with the non optimized and the same type of prediction methods, the average mean square error of prediction is reduced by about 28%, 21% and 3% respectively, and the prediction accuracy is improved to a certain extent. [ABSTRACT FROM AUTHOR]

Aim. The theoretical and experimental studies of the effectiveness of reducing the level of the magnetic field in two-storey cottage of the old building of a power transmission line with a horizontal arrangement of wires by means of active shielding with single compensation winding. Methodology Spatial location coordinates of the compensating winding and the current in the shielding winding were determined during the design of systems of active screening based on solution of the vector game, in whith the vector payoffs is calculated based on Biot-Savart's law. The solution of this vector game calculated based on algorithms of multi-swarm multi-agent optimization. Results The results of theoretical and experimental studies of the effectiveness of reducing the level of the magnetic field in two-storey cottage of the old building of a power transmission line with a horizontal arrangement of wires by means of active shielding with single compensation winding are presented. Originality. For the first time, the theoretical and experimental studies of the effectiveness of reducing the level of the magnetic field in two-storey cottage of the old building of a power transmission line with a horizontal arrangement of wires by means of active shielding with single compensation winding are considered. Practical value. From the point of view of the practical implementation it is shown the possibility to reduce the level of magnetic field in two-storey cottage of the old building from power transmission line with a horizontal arrangement of wires by means of active shielding with single compensation winding to the sanitary standards of Ukraine.

The long-span Cross-Rope Suspended (CRS) system is composed of a transmission line (conductor), a long-span suspension cable, and an insulator. The previously introduced long-span CRS with a Tension Insulator (CRSTI) has shown applicability in mountainous areas. However, the tension insulator divided the suspension cable into several sections, which made the construction of a long-span CRS rather difficult. This paper introduces long-span CRS with a Suspension Insulator (CRSSI), in which the suspension cable was not disconnected, and the conductor was supported by a suspension insulator connected to the suspension cable. For the purposes of assessment, the initial shape of the suspension cable with concentrated loading from the self-gravity of the suspension insulator and the conductors was studied, and practical lengths in construction could be calculated exactly. Secondly, the structural performance of CRSSI, including its dynamic properties and the loading effect of wind, was discussed by means of numerical analysis. Vibration modes of the structure were obtained by FE analysis. Finally, structural deformation under static wind loading was studied. The result of the analysis showed that the stiffness of CRSSI was lower than CRSTI. The first frequency of CRSSI was 6% smaller than CRSTI. Regarding static wind loading, additional displacement of the insulator contributed to the maximum displacement of long-span CRSSI. Apparently, the displacement of the suspension insulator increased with wind speed. Moreover, the number of spans has an insignificant influence on tension force and deformation.

The paper deals with elaboration of hexaphase symmetrical components filters and their modeling to create microprocessor-assisted relay protection of self-compensating power lines. The theory is presented and the basic principial electrical schemes and mathematical models in the Matlab/Simulink of the filters of the hexaphase symmetric components are elaborated. The results of their simulation and testing at the computer are presented. The obtained results demonstrate the possibility of creating in the base on the elaborated filters of hexaphase symmetrical components the modern, efficient and highsensitivity microprocessor-assisted relay protection of self-compensating power lines. What reacted not to phase electrical values, but symmetrical components of them.

The demand for real-time efficient scene comprehension has been increasing rapidly in the drone-based automatic inspection of power transmission lines (PTL). The extensive application of semantic segmentation in urban scenes proves that it can meet the requirements for scene understanding. However, existing methods have difficulty adapting to changes in the scene, which leads to problems of performance degradation and fuzzy contours of segmented objects. To overcome the existing problems, a class-aware edge-assisted lightweight semantic segmentation network is proposed in this paper. Class-aware edge detection is introduced as an auxiliary task, and a two-branch network is designed to locate instances and refine contours. Specifically, hybrid graph learning uses task-specific graph-based structures to reason attention information of region and edge features. Based on the complementary characteristic of region and edge features, cascaded shared decoders adopt specific interaction functions to enhance the ability of region features to locate targets and the ability of edge features to improve contour details. In addition, to verify the effectiveness of the proposed method, we construct two datasets named the transmission tower component recognition dataset (TTCRD) and the transmission line regional classification dataset (TLRCD). Comprehensive experiments on TTCRD and TLRCD prove that the proposed method can accurately refine the contour of objects and overcome the challenges in the two datasets. Comparison experiments and ablation experiments also demonstrate the superior performance of the proposed method and the effectiveness of each component in our architecture. [ABSTRACT FROM AUTHOR]

The application potential of aluminium conductor composite core (ACCC) conductors in the 1000‐kV power transmission line project deserves to be investigated. Its economic evaluation is a contentious issue. This paper proposes a method for selecting the type of conductors based on the life cycle cost (LCC) of a transmission line, which includes the initial investments, operation costs, maintenance costs, failure costs, and discard costs. The mathematical model of electromagnetic loss differs due to the various operational circumstances surrounding a transmission line; therefore, a novel three‐dimensional electromagnetic–fluid–thermal coupling model based on the finite element method (FEM) was proposed. The simulation error of ACCC and aluminium conductor steel reinforced (ACSR) conductors is 2.56% and 0.5%, respectively, compared to the experimental value. Subsequently, the LCC model is applied in the economic analysis of a 1000‐kV transmission line, and the costs of ACCC conductors and ACSR conductors under different annual power load utilization hours are calculated. The results indicate that the overhead power transmission line with ACCC conductors saves at least 2 × 106 ¥/km compared with ACSR when annual utilization hours reach 3500 h; meanwhile, energy saving benefits are achieved. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Engineering Technology is the property of Editorial Department of Electric Power Engineering Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The stability of the inspection robot during crossing the jumper lines of the live lines of the 110kV power transmission is very important. In this study, a novel inspection robot was designed, equipped with a centroid adjusting mechanism to increase the stability during crossing the jumper line. The various obstacle crossing modes of the robot and the corresponding planning are designed. The dynamic modeling method for the rigid-flexible coupling of the robot in the flexible cable environment is studied, which helps to understand the influence of the robot on the transmission line in the environment. The simulation is carried out to analyze the deformation of the jumper line when the robot is on it. The results can be utilized to plan the motion to improve the robot’s efficiency and stability when the robot crosses the jumper line.

The questions of the determination of the fault location (DFL) of a power transmission line by the instantaneous values of currents and voltages observed on two sides were examined. There is no universal criterion of the DFL based on instantaneous values. The task is to search for a general approach to the construction of criteria that conform to the substance of the observed processes. Such an approach is the division of the observed values into two components – local and normal. The local mode is created in the transmission line model by an unknown source acting at the point of the short circuit. Significantly, the model inputs are shunted. There is the possibility of training the indicator of the determination of the fault location in local mode and obtaining its priori characteristics, activating the model in various places of probable fault, and recording local currents at the shunt inputs. In addition to the training stage, to which the main attention is paid, the fault location algorithm itself is also examined. This includes the determination of the normal mode of currents as the reaction of the model of an undamaged line to observed voltages, and determination of local currents as the differences between the observed and normal currents. [ABSTRACT FROM AUTHOR]

The commonly used fault diagnosis method of the power transmission line (PTL) is the traveling wave method which uses the traditional mode components α , β and o to realize the fault type recognizing and the fault location in distribution network. However, the traditional mode components of the traveling wave method may take the value of zero that cannot provide the effective fault feature for the A-phase ground fault, or the A and B double phases short-circuit fault. Moreover, a single traditional mode component cannot recognize all the types of the faults, and the fault recognition has to use the multiple mode components that increases the complexity. To address the aforementioned issues, this paper proposes an edge computing scheme based on a novel mode component γ for PTL fault diagnosis in distribution network. Firstly, the novel mode component γ is fused according to the traditional mode components α and β , then the propagation property of the traveling wave- γ is derived. Secondly, the edge computing scheme and the PTL fault diagnosis method are designed for distribution network by using the only novel mode component γ . Thirdly, the relationship table of the fault type and the boundary conditions as well as the component γ expressions is derived for the fault recognition using the only traveling wave- γ . In addition, the fault distance computing is explored by using the traveling wave- γ . The computing is composed with the wave- γ head identification using the optimal Wavelet vanishing moment parameter, and the arrival time determination, and the fault location method. To evaluate the efficiency of the proposed edge computing scheme, the simulation experiment and the laboratory tests are conducted. The simulation experiment results show that, the novel mode component γ not only provides the effective fault features for all the ten types of the power transmission line faults, but also increases fault locating accuracy by the average 2.08 % compared with the methods using the traditional mode component α , β and o. Meanwhile, the laboratory tests show that the edge computing method is practical. [ABSTRACT FROM AUTHOR]

Aim. The theoretical and experimental studies of the effectiveness of reducing the level of the magnetic field in two-storey cottage of the old building of a power transmission line with a horizontal arrangement of wires by means of active shielding with single compensation winding. Methodology Spatial location coordinates of the compensating winding and the current in the shielding winding were determined during the design of systems of active screening based on solution of the vector game, in whith the vector payoffs is calculated based on Biot-Savart's law. The solution of this vector game calculated based on algorithms of multi-swarm multi-agent optimization. Results The results of theoretical and experimental studies of the effectiveness of reducing the level of the magnetic field in two-storey cottage of the old building of a power transmission line with a horizontal arrangement of wires by means of active shielding with single compensation winding are presented. Originality. For the first time, the theoretical and experimental studies of the effectiveness of reducing the level of the magnetic field in two-storey cottage of the old building of a power transmission line with a horizontal arrangement of wires by means of active shielding with single compensation winding are considered. Practical value. From the point of view of the practical implementation it is shown the possibility to reduce the level of magnetic field in two-storey cottage of the old building from power transmission line with a horizontal arrangement of wires by means of active shielding with single compensation winding to the sanitary standards of Ukraine. References 48, figures 14. [ABSTRACT FROM AUTHOR]

The tasks of phase selection (recognition of damaged phases) and location (determination of the fault location) are solved by a universal algorithm for monitoring an arbitrary site of the presumed fault location. The currents and voltages observed on one side are converted into estimates of the electrical quantities at that location, which are determined on the assumption that the line is not damaged before that position. The converter is an algorithmic model of the initial section of the line with variable length. The algorithmic model is created based on a priori information about the line parameters. Information about the structure and parameters of the rest of the network is required to determine a priori coordinate functions that express the currents in the damage branches through the components of the output voltages or currents of the algorithmic model. The type of components is determined by the completeness of the observer's information base. The most valuable emergency components in terms of information are available, when a short circuit (SC) occurs against the background of the previous mode. However, in the situation when voltage is applied to an already damaged line, then one must be satisfied with the components of the zero and negative sequences. The null value of the reactive power of all damaged phases serve as the criterion for determination of the fault location (DFL), and the boundary conditions for single- and two-phase short circuits as the criterion for phase selection. The tasks of selection and location are closely intertwined. Generally speaking, a complete information base provides an opportunity to perform the detection and ranging without regard to the type of short circuit. But this will be a preliminary estimate of the location of the short circuit. Recognition of damaged phases will result in its refinement. But with an incomplete information base, phase selection certainly precedes location. [ABSTRACT FROM AUTHOR]

The use of drones to inspect transmission lines is an important task for the energy maintenance department to ensure the stability and safety of power transmission. However, the current electric power inspection is inseparable from the participation of artificial vision. It is necessary to establish an automatic visual recognition technology with high reliability, high flexibility, and low embedded cost. This paper develops an improved YOLOv5S deep-learning-based transmission line disaster prevention safety detection model, called Model E. Compared to the original network, we use the Ghost convolution operation in the Model E network to improve the redundant computation caused by the conventional convolution operation. The BiFPN network structure is adopted to enhance the feature extraction ability of the original PANet network for unsafe objects in the transmission line image. This occurs in the process of Model E transmission line disaster prevention safety detection model learning. Equalized Focal Loss (EFL) is used to improve the Model E sample imbalance problem processing mechanism. The Model E proposed in this paper is 6.9%, 1.7%, 1.7%, and 2.9% higher than the current lightweight mainstream algorithms YOLOv3-Tiny and YOLOv5S, Model C (based on the original YOLOv5S network, the BiFPN structure in the Model E network part is improved), and Model D network (in the Backbone layer, four conventional convolutions are improved as Ghost convolution operations, and the rest of the structure is the same as the Model E network) in mAP@.5 evaluation index. Meanwhile, the size of the model is only 79.5%, 97.7%, 84.9%, and 93.8% of the above algorithm model. The experimental results show that the Model E transmission line disaster prevention and safety detection model proposed in this paper shows stronger competitiveness and advancement, with high reliability, flexibility, and fast detection ability, and can be applied to cost, reliability, and efficiency in order to have a higher standard of practical engineering needs. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the recent development in power electronic devices, HVDC (High Voltage Direct Current) systems have been recognized as the most prominent solution to transmit electric power economically. Today, several HVDC projects have been implemented physically. The conventional HVDC systems use grid commutation converters, and its commutation relies on an AC system for the provision of voltage. Due to this reason, there are possibilities of commutation failure during fault. Furthermore, once the DC (Direct Current) system power is interrupted momentarily, the reversal of work power is likely to cause transient over-voltage, which will endanger the safety of power grid operation. Hence, it is necessary to study the commutation failure and transient over-voltage issues. To tackle the above issues, in this paper, the dynamic and transient characteristics of Pakistan's first HVDC project, i.e., the Matiari–Lahore ±660 kV transmission line has been analyzed in an electromagnetic transient model of PSCAD/EMTDC. Based on the characteristics of the DC and the off-angle after the failure, a new control strategy has been proposed. The HVDC system along with its proposed control strategy has been tested under various operating conditions. The proposed controller increases the speed of fault detection, reduces the drop of AC voltage and DC and suppresses the commutation failure probability of LCC-HVDC (line commutated converter- high voltage direct current). [ABSTRACT FROM AUTHOR]

This paper reports a study into the influence of the main design parameters of power transmission lines on energy losses associated with the corona discharge; a method has been devised to reduce them. The structure of the split-phase wire, the distance to the ground, and between the centers of the phases of the line are determined at the design stage. Based on these structural parameters, the value of specific energy losses associated with the corona discharge is calculated. Studying the impact exerted on the amount of losses by each structural parameter makes it possible at the design stage to determine the structure of a power transmission line (PTL) with low energy losses. Reducing energy loss when transporting it along the line is one of the most important issues in the strategy for the development of the energy industry at the stage of the “green transition”. It has been established that most structural parameters have a weak effect on the values of corona losses, and, if there is a significant impact, the implementation of such solutions leads to a large increase in the cost of constructing an overhead transmission line. Based on the analysis of the results of calculations of corona losses in power transmission lines, it was determined that the corona losses in the middle phase of the transmission line are much greater than in the extreme phases. That has made it possible to devise a method for reducing power corona losses associated with the alignment of the capacities of all phases of PTL. This effect is achieved by calculating, based on the developed method, the splitting step of the middle phase of PTL. The calculation of the splitting step is based on the preliminary determination of the capacity of the extreme phases and the substitution of calculated values in the resulting expression for the splitting step. The possibility of such a reduction in corona losses should significantly increase the energy efficiency of AC power transmission lines, especially in areas with large periods of different weather that provoke the occurrence of a corona discharge on the wires of their phases. This circumstance causes an increase in this type of power loss [ABSTRACT FROM AUTHOR]

The present study aims to provide a suitable approach to optimize transmission line towers with size, shape and panel design variables. MSTOWER software was used for modeling, analysis and design of the transmission tower. The design requirements applied to the structure were in accordance with ASCE10-97 standard. Transmission line towers are optimized in two ways. The first method combines Biogeography based Optimization (BBO) algorithm with MSTOWER software called BBO-MSTOWER and the second method, called BBO-ANFIS, uses an adaptive fuzzy neural inference system (ANFIS). To analyze the structure in the optimization process with the aim of reducing the computations and time of the optimization process. In order to evaluate the proposed method, two full-scale transmission towers were optimized as numerical models using the above two methods. Finally, the optimal design and time required in the two optimization methods were compared with each other as well as with the initial design of the tower and the results reported in previous studies. The results showed that with acceptable accuracy, ANFIS resulted in a significant reduction in the calculation time of the entire optimization process. [ABSTRACT FROM AUTHOR]

In mountainous areas, the installation of steel towers was the major obstacle to the construction of transmission lines. In long-span cross-rope suspension (CRS) structures, the conductors are supported by hundreds-meters-long suspension cables crossing valleys instead of steel towers. Though long-span CRS is an innovative structural system, its structural performance needs to be clarified. Firstly, an assembled FE model was established based on initial deformed components for long-span cross-rope suspension structure. The wind load response of long-span cross-rope suspension structure with different lengths or number of spans was established and analyzed. Vortex-induced vibration (VIV), which was the major factor regarding fatigue and service life, and its controlling by Stockbridge damper for a long-span CRS were discussed. The numerical simulation results showed that the tensile force of the suspension cable increased with the length and number of spans of the conductor. In addition, considering the ice covering the transmission line, the interaction between the wind load and ice load induced the nonlinear lateral deformation characteristics of the conductor. Moreover, the vibration characteristics of the conductor in the long-span CRS were studied and compared with the traditional tower-line system. An analysis of the long-span CRS with a Stockbridge damper showed that additional dampers were essential for controlling the maximum dynamic bending stress of conductors at both ends. [ABSTRACT FROM AUTHOR]

Copyright of Geomatik is the property of Murat Yakar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dry and ice galloping of power transmission lines (conductors) that occur at moderate to large wind speeds cause large-amplitude motion in these long-suspended cables. This phenomenon can cause catastrophic damages such as flashover, wire burning, tripping, transmission line tower collapse, accident, interphase short circuit, and structural or fatigue failure of transmission towers or conductors. Wind-induced cable vibration, which has been extensively studied, can be classified based on its sources, such as rain-wind-induced vibration (RWIV), vortex-induced vibration (VIV), wake galloping, and dry/ice galloping. This study primarily focuses on the predictions of time-domain response and onset of dry- and ice-conductor galloping by measuring the self-excited and buffeting load parameters of the bare conductors and conductors with ice formation in normal and yawed wind. In this regard, a series of static and dynamic wind tunnel experiments were performed to fundamentally study the conductor vibration in dry and ice conditions. Surface pressure distribution and aerodynamic forces were measured for stationary section models of nonyawed and yawed dry conductors in a smooth flow. Additionally, the dynamic response of dry and iced conductors using a one-degree-of-freedom system was recorded by employing a free vibration setup to extract self-excited load parameters. Buffeting load parameters were measured by generating a sinusoidal-oscillating wind upstream of dry and iced conductors for different yaw angles. The experiments resulted in the identification of the Strouhal number (St), aerodynamic load coefficients (CD and CL), buffeting indicial derivative functions, aerodynamic stiffness, and aerodynamic damping of a conductor for yaw angles (β) ranging from 0° to 45°. Dynamic tests led to the proposing of several empirical equations to determine the critical reduced velocity (RVcr) or critical wind speed for dry and ice galloping of conductors at a given Scruton number (Sch) and yaw angle. Finally, a procedure was proposed to calculate the least damping required to suppress the conductor galloping under dry or iced conditions up to the design wind speed. The wind load parameters identified in this study can be used to numerically simulate the dynamic load and response in the time domain of dry and iced conductors in turbulent wind. [ABSTRACT FROM AUTHOR]

The transmission line is one vital component of electrical power system. It determines some fundamental characteristics such as transmission efficiencies, voltage drops and line losses which are important matters to be considered in system planning, design and maintaining. The so-called PI-based modeling refers to using basic PI (proportional and integral) elements as well as other basic elements to implement one specific simulation. Grounded on the distributed-element model and addressing complex-element modeling, one PI-based simulation method is introduced in this study for teaching purposes and applied to modeling and simulation for performance testing of the power transmission line. The proposed method is demonstrated in the Simulink simulation environment and verified by performance testing of the power transmission line including complex-element-based equivalent distributed-element modeling for (short, medium and long) transmission lines, load flow analysis, short circuit test, open circuit test and the "Ferranti-effect" phenomenon, SIL (surge impedance loading) and series and shunt compensation simulation. Results indicate workability of the proposed method that it provides one convenient and vivid way for complex-element-based simulation modeling and solving numerical solutions as well. The proposed PI-based method for complex-element modeling and its Simulink-based simulation approach may be useful for related electrical engineering simulations and testing. • Only basic PI (proportional and integral) elements and other basic elements are employed for complex-element modeling. • Applied to modeling and simulation for performance testing of the power transmission line. • PI-based complex-element modeling method with simulation results may be useful for related electrical engineering simulation and testing. [ABSTRACT FROM AUTHOR]

The slope crest foundation is a common type of foundation which is often used in power transmission line through the slopes terrain,the study on the uplift bearing capacity of this foundation is still at the initial stage in China.Firstly,the parameter inversion of rock mass mechanics parameters were inversed by FLAC3D based on the results of in-situ test on the flat ground in Anhui.Secondly,138 numerical simulations of slope crest foundation were calculated according to the different distances between slope shoulder and foundation edge,foundation depths and slope angles by using the inversion parameters.And it is concluded that the failure modes of the slope crest foundation can be divided into the shallow buried mode and the deep buried mode by comparing the vertical and horizontal displacement nephogram and the plastic zone distribution of the simulation results.Meanwhile,based on the analysis of the decay rate of ultimate uplift load,it is summarized that the uplift bearing capacity of slope crest foundation increased with the increase of the distance between slope shoulder and foundation edge and foundation depth,but decreased with the increase of slope angle.The concept of minimum safe top distance of slope foundation is proposed to provide scientific basis and reference for design and construction of transmission line slope foundation.

A new approbation of the previously presented method for recognizing a failed branch in one-sided observation of a power transmission line has been carried out. A real line of short length with four branches, two of which are almost identical, is considered. The line connects a high-power source with a low-power one. Each branch is characterized by an a priori hodograph, and the observed mode is displayed by a coordinate hodograph, the expected intersection of which with the a priori hodograph of the failed branch should occur when the coordinates of the branch and the hodograph coincide. An ambiguity of the solution was found when one of the identical branches was failed, if the observation was carried out from the sending side of the line. However, when the observation was carried out from the receiving side, the failure was unambiguously recognized. It is shown that unambiguous recognition can also be provided from the sending side of the line by resorting to cascade disconnection of the line. [ABSTRACT FROM AUTHOR]

The use of drones to inspect transmission lines is an important task for the energy maintenance department to ensure the stability and safety of power transmission. However, the current electric power inspection is inseparable from the participation of artificial vision. It is necessary to establish an automatic visual recognition technology with high reliability, high flexibility, and low embedded cost. This paper develops an improved YOLOv5S deep-learning-based transmission line disaster prevention safety detection model, called Model E. Compared to the original network, we use the Ghost convolution operation in the Model E network to improve the redundant computation caused by the conventional convolution operation. The BiFPN network structure is adopted to enhance the feature extraction ability of the original PANet network for unsafe objects in the transmission line image. This occurs in the process of Model E transmission line disaster prevention safety detection model learning. Equalized Focal Loss (EFL) is used to improve the Model E sample imbalance problem processing mechanism. The Model E proposed in this paper is 6.9%, 1.7%, 1.7%, and 2.9% higher than the current lightweight mainstream algorithms YOLOv3-Tiny and YOLOv5S, Model C (based on the original YOLOv5S network, the BiFPN structure in the Model E network part is improved), and Model D network (in the Backbone layer, four conventional convolutions are improved as Ghost convolution operations, and the rest of the structure is the same as the Model E network) in mAP@.5 evaluation index. Meanwhile, the size of the model is only 79.5%, 97.7%, 84.9%, and 93.8% of the above algorithm model. The experimental results show that the Model E transmission line disaster prevention and safety detection model proposed in this paper shows stronger competitiveness and advancement, with high reliability, flexibility, and fast detection ability, and can be applied to cost, reliability, and efficiency in order to have a higher standard of practical engineering needs.