Line Components Research Articles

İSTİSMARDAKI KABELLӘRDӘ ZӘDӘLӘRİN ARADAN QALDIRILMASININ MÜASİR ÜSULLARI

XLPE insulated power cables serve as essential components in medium and high voltage power transmission lines, yet maximizing their resource duration poses a significant challenge for consumers. Issues such as water treeings, electric treeings, and partial discharges within the insulation system accelerate cable aging over time. In response, a novel approach has been proposed in this study to mitigate these detrimental factors. The method involves injecting a specially formulated liquid into the cable insulation to address inhomogeneities, effectively rejuvenating the cable and extending its service life by 20-30 years, as indicated by the technology's name. Furthermore, to provide context on the practical implications, a succinct analysis of the Azerbaijani cable network is presented in this article. Also, in order to explain the real situation of power cables, a brief analysis of the Azerbaijani cable network was conducted in the article.

Yellow hypergiant V509 Cas: Stable in the ‘yellow void’

Context. The yellow hypergiant star V509 Cas is currently undergoing an extreme phase of evolution. Having experienced eruptive mass-loss outbursts in the 20th century, the star’s effective temperature reached record high values in the early 2000s. However, since then, the star’s behaviour has displayed an unprecedented level of stability. In spite of that, the star could be traversing through the ‘yellow void’ instability region. Aims. To describe the current evolutionary state of V509 Cas, we analysed its variability using photometric and spectroscopic data collected over recent years. By comparing our findings with historical records, we aim to determine whether the star’s surface shows signs of stabilisation. Additionally, we investigate the variability of emission components in the wings of certain spectral lines to highlight the contribution of the circumstellar gaseous disc to this phenomenon. Methods. Our spectroscopic monitoring observations were carried out at Tartu Observatory over the course of seven years, supplemented by echelle spectra obtained at the Nordic Optical Telescope, as well as publicly available photometric data from Gaia, AAVSO, and AAVSO’s Bright Star Monitor programme. We estimated the variability of effective temperature and radial velocity from the spectral time series and correlated it with the brightness variability of V509 Cas. Results. The results indicate that the star’s average brightness level has remained stable throughout the observed period, with an amplitude of variability ∼0.1 mag. While the amplitude of short-term temperature fluctuations has decreased compared to the early 2000s, the variability of the radial velocity remains similar to historical values from the early 20th century. Moreover, we show how the variable radial velocity affects the emission components in some absorption lines (e.g. Sc II) and how that follows the hypothesis of a disc surrounding the star.

Aerial Inspection of High-Voltage Power Lines Using YOLOv8 Real-Time Object Detector

The aerial inspection of electricity infrastructure is gaining high interest due to the rapid advancements in unmanned aerial vehicle (UAV) technology, which has proven to be a cost- and time-effective solution for deploying computer vision techniques. Our objectives are focused on enabling the real-time detection of key power line components and identifying missing caps on insulators. To address the need for real-time detection, we evaluate the latest single-stage object detector, YOLOv8. We propose a fine-tuned model based on YOLOv8’s architecture, trained on a custom dataset with three object classes, i.e., towers, insulators, and conductors, resulting in an overall accuracy rate of 83.8% (mAP@0.5). The model was tested on a GeForce RTX 3070 (8 GB), as well as on a CPU, reaching 243 fps and 39 fps for video footage, respectively. We also verify that our model can serve as a baseline for other power line detection models; a defect detection model for insulators was trained using our model’s pre-trained weights on an open-source dataset, increasing precision and recall class predictions (F1-score). The model achieved a 99.5% accuracy rate in classifying defective insulators (mAP@0.5).

Behind the curtain of sustainable business models: the role of firm’s strategic agility in value creation

PurposeThis paper aims to identify the archetypes of business models and illustrate how firms create, deliver and capture value by juxtaposing the firm’s aspired value emphasis with its strategic agility.Design/methodology/approachThe two-by-two matrix is constructed based on an analysis of existing literature and conceptual development.FindingsWe advance a conceptualization of strategic agility to emphasize speed and flexibility as the main drivers, along with attention toward stakeholder expectations. Additionally, we unveil four different archetypes of business models based on the firm’s aspired value emphasis (economic vs plus social/environmental) and the type of strategic agility (defensive vs proactive).Research limitations/implicationsStudies that empirically corroborate the proposed conceptualization of strategic agility are needed. In addition, empirical investigations on the evolutionary paths underlying the development of firms’ business models are requested.Practical implicationsManagers learn about aspects and actions that they should pursue to shift from one business model archetype to another.Originality/valueWe identify the features – in terms of focus on all the components of the triple bottom line (or not) and in terms of strategic agility – that firms need to face or even anticipate environmental and social transformation.

Judgment criteria for significant wind speed-up regions in natural complex terrain

Flashover incidents due to wind-induced motion of overhead power line components are a not uncommon phenomenon during very strong winds, e.g. typhoons, and an important contributing factor is the speed-up effect caused by small-scale topographic features. In this study, wind speed-up ratios and significant speed-up regions in natural complex terrain are comprehensively analyzed from three perspectives: analysis of landform characteristics of flashover locations, Computational Fluid Dynamics (CFD) simulation, and wind tunnel experiments. Through the analysis of flashover locations, judgment criteria based on the elevation coefficient of variation are proposed to attempt to identify significant speed-up regions in natural complex terrain. Wind tunnel experiments and CFD simulations are conducted to analyze the wind speed-up ratios in 12 wind directions for both a small isolated mountainous area and a large continuous mountainous area. The significant speed-up regions are determined by consolidating the speed-up ratios from all 12 wind directions. The reliability of the judgment criteria is then validated. The results confirm that significant speed-up ratios are predominantly concentrated at the edges of mountainous areas, particularly at peaks and high ridges around areas with larger elevation coefficient of variation. These regions largely coincide with the locations where flashover incidents mainly occurred and the results from wind tunnel experiments and CFD simulations. In summary, the clearly identified significant speed-up regions include (1) small isolated mountainous areas; (2) peaks and high ridges around areas with larger elevation coefficient of variation within large continuous mountainous areas, and the higher crests within these regions. Based on these findings, the study suggests that wind speed-up ratios in design standards should be amplified in the vicinity of these regions to enhance safety measures.

Coupling characteristics between MMC-HVDC and AC transmission lines on the same tower and their impact on protective relaying

Significant coupling exists between DC and AC lines erected on the same tower or sharing transmission corridors. Electromagnetic and electrostatic coupling between DC and AC lines are investigated based on ± 500 kV MMC-HVDC and 500 kV double-circuit AC lines on the same tower. The interactive coupling characteristics and their impacts on protective relaying are analyzed during normal operation and after DC or AC faults. Voltage coupling ratio and current coupling ratio are defined. The 50 Hz components in MMC-HVDC line may be higher than ripple criterion under the coupling of AC line and can be even more significant when a fault occurs on adjacent AC line. The DC reactor with larger inductance can reduce its impact on MMC-HVDC system. Zero-sequence overcurrent relaying and zero-sequence directional relaying for AC lines may mal-operate when a fault occurs on adjacent MMC-HVDC line. And there is also an interruption risk for AC systems. Improvement schemes are proposed to avoid the mal-operation of protective relaying. Simulation case studies verify the correctness of coupling characteristic analysis and the effectiveness of proposed improvement scheme.

First Detection of Outflowing Gas in the Outskirts of the Broad-line Region in 1H 0707−495* *Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia e Inovações do Brasil (MCTI/LNA), the US National Science Foundation's NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State

We use near-infrared spectroscopy covering simultaneously the zJHK bands to look for outflowing gas from the nuclear environment of 1H 0707−495 taking advantage that this region is dominated by low-ionization broad-line region lines, most of them isolated. We detect broad components in H i, Fe ii, and O i, at rest to the systemic velocity, displaying FWHM values of ∼500 km s−1, consistent with its classification as a narrow-line Seyfert 1 active galactic nucleus. Moreover, most lines display a conspicuous blue-asymmetric profile, modeled using a blueshifted component, whose velocity shift reaches up to ∼826 km s−1. This last feature can be interpreted in terms of outflowing gas already observed in X-ray and UV lines in 1H 0707−495 but not detected before in the low-ionization lines. We discuss the relevance of our findings within the framework of the wind scenario already proposed for this source and suggest that the wind extends well into the narrow-line region owing to the observation of a blueshifted component in the forbidden line of [S iii] λ9531.

Hauling Snow Crab Traps in Eastern Canada: A Study Documenting Tension in Ropes

Entanglement in commercial fishing gear is one of the main factors inhibiting the recovery of critically endangered North Atlantic right whales. Installing low-breaking-strength (LBS) components in the buoy lines and main lines of stationary fishing gear may be a viable solution for some fisheries. But is it an effective solution for deep-water trap fisheries? This study quantified in-line rope tensions observed during fishing operations for snow crab (Chionoecetes opilio) in Newfoundland and Labrador, Canada. We conducted a controlled fishing experiment in which we documented the loads experienced while hauling fleets of traps. The results showed that several factors contributed to the loads observed, including the components of the traps, the presence of crabs, and environmental conditions such as wind direction and wave height. According to the statistical models, the maximum tension from the estimated marginal means was 477.53 kgf in the buoy line and 987.99 kgf in the main line for the baited hauls, which exceeds the safe working load (154 kgf) of the proposed low-breaking-strength components. Our results suggest that LBS components are not a viable solution for this deep-water fishery.

Modeling Copper Alloy Corrosion in Underground Service Line Components

Key TakeawaysIt's important for the water industry to determine which corrosion tests are suitable to evaluate potential alloys for service line components buried underground.Two dezincification tests were effective at correlating to field experience.Electrochemical corrosion tests using “low‐ and high‐corrosive” synthetic soil with neutral pH were not generally effective in predicting field experience.

SOD-YOLO: A High-Precision Detection of Small Targets on High-Voltage Transmission Lines

Wire clamps and vibration-proof hammers are key components of high-voltage transmission lines. The wire clips and vibration-proof hammers detected in Unmanned Aerial Vehicle (UAV) power inspections suffer from small size, scarce edge information, and low recognition accuracy. To address these problems, this paper proposes a small object detection (SOD) model based on the YOLOv8n, called SOD-YOLO. Firstly, an extra small target detection layer was added to YOLOv8, which significantly improves the small target detection accuracy. In addition, in order to enhance the detection speed of the model, the RepVGG/RepConv ShuffleNet (RCS) and a OneShot Aggregation of the RCS (RCSOSA) module were introduced to replace the C2f module in the model backbone and neck shallow networks. Finally, to address the excessive focus on low-quality sample bounding boxes during model training, we introduced Wise-CIoU loss instead of CIoU loss, which improved the detection accuracy of the model. The experimental results indicate that SOD-YOLO achieved a mean average precision of 90.1%, surpassing the YOLOv8n baseline model by 7.5% while maintaining a model parameter count of 3.4 M; the inference speed reached 88.7 frames/s, which meets the requirement of real-time recognition.

Design and comparative analysis of alternative mooring systems for offshore floating photovoltaics arrays in ultra-shallow water with significant tidal range

Large-scale floating photovoltaics (FPV) are garnering increased attention as a sustainable solution for renewable energy production and efficient utilization of ocean spaces. These FPV arrays are predominantly deployed in shallow water environments, which present significant challenges in mooring system design due to substantial tidal fluctuations. In such settings, mooring systems may become slack and lose functionality at low tide or risk damage from excessive stiffness at high tide. The primary aim of this study is to develop a mooring system tailored to FPV arrays, capable of withstanding extensive tidal variations without causing damage to the floating modules due to high mooring line tension. Employing HydroD, a hydrodynamic analysis tool based on potential flow theory, alongside OrcaFlex, a time-domain coupled analysis tool predicated on the lumped mass method, we conducted a comparative assessment of six distinct mooring configurations. These configurations, varying in mooring line materials and components, were evaluated from static, dynamic, and fatigue analysis standpoints across a range of tidal levels. The results indicate that taut mooring systems integrated with buoys or clumps consistently exhibit superior performance in all test scenarios. Accordingly, these systems are highly recommended for securing FPV arrays in shallow water environments characterized by severe tidal variations, offering optimal stability and resilience.

Big data driven supply chain innovative capability for sustainable competitive advantage in the food supply chain: Resource‐based view perspective

AbstractThe food supply chain (FSC) is becoming more sustainable as companies aim to meet demand with lower waste and emissions. Big data analytics (BDA) can help achieve sustainability goals by extracting meaningful information from past data to help create sustainable strategies. However, in the sustainability literature, BDA's role in enabling sustainable FSC innovations is not explored. Thus, this study investigates how data‐driven analytics might improve FSC innovation by adopting creative tactics in every triple bottom line (TBL) component – green, corporate social responsibility (CSR), and financial – to gain a competitive edge. A resource‐based view (RBV) perspective was used to evaluate the links between supply chain (SC) innovation capabilities and competitive advantage (CA) in FSC innovation and sustainability. Indian food processing enterprises were surveyed using a questionnaire to collect data from 200 respondents. Adopting a structural equation modelling (SEM) approach, six hypotheses were evaluated for significance on the surveyed data using AMOS V.20. Since both goodness and badness fit indices were above cut‐off values, the measurement model was robustly evaluated and found to fit the survey data well. Structural model findings supported all study hypotheses. The results indicate that BDA strongly impacts food supply chain TBL and FSC innovation. Data‐driven innovative TBL methods were shown to boost FSC competitiveness. With the growing demand for value‐added innovation in FSC sustainable development, this study uniquely contributes to the current literature by linking BDA and TBL practice innovation to FSC CA.

A perturbed energy level of the holmium atom

This study focuses on two lines of atomic holmium for which standard hyperfine structure analysis could not be performed. The lines were studied by laser-induced fluorescence spectroscopy using a Ti-sapphire laser. Usually, the hyperfine structure of spectral lines is described by the well-known Casimir formula. However, this was not possible in the analysis of these two lines. The common feature of these two lines is that their upper energy levels are identical. In this study, hyperfine structure analyses were performed by considering a perturbation in the hyperfine splitting of the upper energy level of both lines. Shifts were introduced for the hyperfine sub-levels with F = 4 to 7 of the perturbed level, with the help of which the positions of all components of both laser lines could be satisfactorily explained. The same behaviour was found for three other spectral lines present in the Fourier transform spectrum, which are connected to the same perturbed upper energy level. The perturbation must be caused by a hitherto unknown energy level of odd parity with small J -value. The energy, J - quantum number and hyperfine constant A of this level were estimated.

Thermo-mechanical analysis of the components in the launcher transmission line of ITER ex-port plug collective Thomson scattering

ITER Collective Thomson Scattering (CTS) diagnostic system is designed to analyze the alpha particles resulting from Deuterium-Tritium fusion reactions. It consists of one launcher and nine receiver transmission lines. The launcher line transports the high-power microwave emission of 1.2 MW from the gyrotron source to the front-end, while the receiver lines transport the collected microwave emission from the front-end and distribute it to the instrumentation in the Diagnostic Building.Due to the high power transported in the launcher line, it has to be water-cooled to minimize the thermal expansion resulting from the heating caused by the power losses. Therefore, this work primarily focuses on establishing the cooling system parameters for the launcher TL to ensure efficient dissipation of the ohmic losses, while meeting the ITER cooling requirements. Once the parameters of the water cooling system are defined, a thermo-mechanical analysis of the most critical components is performed to assess their temperature distribution and deformations.

Vitamin A Positively Correlates with Secretory Immunoglobulin A: A Cross-Sectional Study in Omicron COVID-19 Outpatients.

Background: Respiratory tract infections remain among the leading causes of mortality worldwide. The COVID-19 pandemic has highlighted the importance of mucosal immunity in defending against infectious agents. Vitamin A is known to influence the production of secretory immunoglobulin A (SIgA) predominantly in the gut, where it is a critical component of the first line of defense on mucosal surfaces. Methods: This cross-sectional study, conducted 14 days post-positive COVID-19 diagnosis, aimed to determine the relationship between the nutritional status of vitamin A and SIgA levels in COVID-19 outpatients. Serum and saliva samples were collected. Vitamin A nutritional status was determined based on the assessment of dietary intake and the analysis of retinol-binding protein 4 (RBP4). SIgA levels were analyzed from salivary samples. In addition, serum antibodies were analyzed. Results: Dietary vitamin A intake and RBP4 levels positively correlated with SIgA. Patients with higher vitamin A intake showed higher SIgA/IgG1 and SIgA/IgG3 ratios, while those with higher RBP4 levels showed higher SIgA/IgM, SIgA/IgG1, and SIgA/IgG2 ratios. Conclusions: These findings underscore a significant correlation between vitamin A nutritional status and SIgA levels in COVID-19 outpatients, which may suggest the potential importance of maintaining optimal vitamin A levels for the prevention of viral infections.

Determination of bioactive components in different tomato lines: Physicochemical properties and antioxidant activity

Tomato, one of the most produced vegetables in the world, is experiencing continuous global increase in both production and consumption. Fruit quality traits are important for fresh market tomatoes as well as for the processing industry. Despite the growing demand for both fresh and processed tomatoes, consumers are not satisfied with the quality of available fruits. The main objectives of the present work were to determine the physicochemical characteristics [pH, total soluble solids (TSS), total titratable acids (TTA), TSS/TTA ratio, DMC, lycopene, β-carotene, vitamin C, and total phenolic content], as well as the antioxidant activity of 13 different tomato lines, and to identify the most promising ones in terms of fruit taste and quality. Antioxidant activity was determined using the ABTS and DPPH methods with Trolox used as the standard compound. PCA analysis was conducted to identify group patterns. The results of PCA analysis indicated a specific genotypic response in all investigated physicochemical traits. Genotypes 2, 10, and 13 were identified as the best for fresh consumption, as they exhibited the highest levels of compounds crucial for good taste, nutrition, and human health benefits. The most promising genotype related to fruit quality attributes was genotype 10 with the best TSS and TAA content and TSS/TAA ratio, which is important for overall taste perception. On the other hand, genotype 9 showed promise for industrial purposes due to its ideal pH value in the juice and good soluble solid content. High antioxidant activity was characteristic of genotypes 1 and 2, and their consumption as fresh tomatoes can be beneficial to human health. They also should be considered for further evaluation as potentially interesting genotypes for abiotic stress research and selection programs which can lead to the development of both superior fruit quality and stress tolerant genotypes.

Distribution system resilience improvement against hurricanes: optimal line hardening according to reconfiguration potentials

AbstractIn recent years, there has been a notable increase in the frequency and intensity of natural disasters related to global warming. Large‐scale blackouts caused by natural disasters demonstrate the extreme vulnerability of power systems to these devastations. Resilience planning is the key to preparing power systems for natural disasters by enhancing the vital infrastructure's robustness. This paper proposes a new resilience improvement framework based on resiliency assessment and optimal hardening to improve the distribution system's resiliency against hurricanes. The main goal is to find the optimal distribution system line hardening solution according to reconfiguration potentials after the hurricane to minimize the distribution system cost of energy not supplied. Fragility curves and Monte Carlo simulations are used for the distribution system resilience assessment. Poles and conductors are vulnerable components of distribution system lines; therefore, two hardening strategies have been outlined using measures like replacing old poles with new poles, upgrading pole classes, and vegetation management. This method is modelled as an optimization program considering budget limitations and load priorities and implemented by a genetic algorithm on the IEEE 33‐bus standard network. The results show that optimal line hardening according to network reconfiguration potentials significantly increased the distribution system's resilience.

Anti-icing application of superhydrophobic coating on glass insulator

Insulators, as important components in transmission lines, are prone to disturb the safe running of the power system by the ice accumulation on surfaces. Traditional anti-icing coatings are difficult to practically apply to insulators. Here, superhydrophobic (SHP) coatings were fabricated on the glass insulator surface by spraying. We studied microstructure, wettability, water droplet bouncing behavior, and anti-glaze icing properties of SHP coating. The results demonstrated that SHP coatings had micro-nano rough structures. The excellent superhydrophobicity (contact angle of 165.2° and sliding angle of 3.7°) was achieved. The water droplet was easily adhered to the surface of the glass insulators. At the same time, individual water droplets could bounce away from the surface after impacting the SHP coating. In the glaze environment, water droplets sprayed onto the SHP coating merged with each other and slid off the surface. These significantly reduce the likelihood of freezing. Furthermore, the SHP coating could dramatically delay the glaze icing and decrease the icing area. The icing weight and icicle length were smaller than glass insulators. The SHP coatings prepared in this work display great potential for the anti-icing of glass insulators.

The MEGARA view of outflows in LINERs

Context. Feedback processes, in particular those driven by outflows, are believed to play a major role in galaxy evolution. Outflows are believed to be ubiquitous in all active galactic nuclei (AGNs), although their presence in low luminosity AGNs, in particular for Low-Ionisation Nuclear Emission line Regions (LINERs), has only started to be explored. Their properties (geometry, mass, and energetics) are still far from being properly characterised. Aims. The main goal is to use integral field spectroscopic data from the MEGARA instrument at the Gran Telescopio Canarias (GTC) to analyse a small sample of nine LINERs, candidates of hosting ionised gas outflows. We aim to study the main emission lines in the optical wavelength range to identify their properties and physical origin. Methods. We obtained data cubes in several bands at the lowest (R ∼ 6000) and highest (R ∼ 20 000) spectral resolution of MEGARA. We modelled and subtracted the stellar continuum to obtain the ionised gas contribution, and then fitted the emission lines to extract their kinematics (velocity and velocity dispersion). We identified outflows as a secondary component in the emission lines and obtained their main properties. Results. The primary component of the emission lines was typically associated with gas in the galactic disc. For some objects, there is an enhanced-σ region typically co-spatial with the secondary component. We associated it to turbulent gas produced due to the interaction with the outflows. We find signatures of outflows in six LINERs, with mass outflow rates ranging from 0.004 to 0.4 M⊙ yr−1 and energy rates from ∼1038 to ∼1040 erg s−1. Their mean electronic density is 600 cm−3, extending to distances of ∼400 pc at an (absolute) velocity of ∼340 km s−1 (on average). They tend to be compact and unresolved, although for some sources they are extended with a bubble-like morphology. Conclusions. Our results confirm the existence of outflows in the best LINER candidates identified using previous long-slit spectroscopic and imaging data. These outflows do not follow the scaling relations obtained for more luminous AGNs. For some objects we discuss jets as the main drivers of the outflows.

A fault detection method for transmission line components based on synthetic dataset and improved YOLOv5

To address insufficient fault images for transmission line components (TLCs) and low accuracy in fault detection using deep learning techniques, we propose a fault detection method for TLCs based on synthetic datasets and improved YOLOv5. First, we introduce a synthetic image approach that uses prior information from the inspection process of a developed flying-walking power transmission line inspection robot (FPTLIR) to generate a synthetic dataset of fault components (SDFC). Second, we propose an improved YOLOv5 network called CSH-YOLOv5 to improve the accuracy of fault detection. The CSH-YOLOv5 network incorporates the convolutional block attention module (CBAM) and the latest SimCSPSPPF module to improve the detection accuracy of the network. In addition, a statistical analysis of small objects in the SDFC is performed and the neck and head of the YOLOv5 network are optimized accordingly to detect small objects. Finally, to address the lack of fault images in the unmanned aerial vehicle (UAV) inspection dataset, we implement a two-stage transfer learning strategy using the SDFC for training. We then experimentally evaluate the performance of the CSH-YOLOv5 network on a real test dataset. The results show that the CSH-YOLOv5 network achieves a mAP@[0.5] of 98.0% and a mAP@[0.5: 0.95] of 64.6% for fault detection, representing an improvement of 7.6% and 8.1%, respectively, over the YOLOv5 network. Comparative analysis indicates that the CSH-YOLOv5 outperforms other popular object detection networks, including Faster-RCNN, YOLOX, and YOLOv7 networks. The two-stage transfer learning strategy employed significantly enhances the network's generalization ability and detection accuracy on the UAV inspection dataset. The proposed method provides a technical reference for fault detection of TLCs, which can potentially benefit the power transmission industry.