Overhead Power Lines Research Articles

Tower Models for Power Systems Transients: A Review

Fast-front transients play an important role in the insulation design of any power system. When a stroke hits the shield wire or the tower of high-voltage overhead power lines, flashover may occur either along the span or across tower insulators, depending on the relevant voltages and insulation strength. As a result, backflashover may take place from the tower structure to the phase conductor whenever a huge impulse current flows along the tower towards considerably high footing impedances. For these reasons, tower modeling for transients studies is an important step in the insulation design, and also for lower voltage applications, where indirect lightning effects may play a predominant role. However, after decades of research on tower modeling, starting from the 1930s with the first model proposed by Jordan, no consensus has been reached neither on a widely accepted tower model nor on the quantitative effect of the tower models on insulation design. Moreover, the fundamental mechanisms at the base of the transient response of towers and the definition of some fundamental parameters have not been totally clarified yet. The aim of this review is to present the available tower models developed through the years in the power community, focussing mainly on lumped/distributed circuit models, and to help the reader to obtain a deeper understanding of them.

Methods for the implementation of automatic reclosing on combined overhead and underground cable power lines 110-500 kV

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

Examination of the Contributing Factors to Fatalities in Electrical Trades Due to Contact With Electricity.

The aim of this study was to examine contributing factors to fatalities in electrical occupations due to contact with electricity. Proportionate mortality ratios were calculated along with the Mantel-Haenszel chi-square test of significance using Occupational Safety and Health Administration data. Cross-tabulation analyses were examined by the Pearson chi-square test of independence. Electricians and electrical power installers/repairers experienced significantly higher proportions of fatalities due to contact with electric current of machine, tool, or light fixture and contact with overhead power lines, respectively. Factors such as accident date, location, union status, project type, cost, electrical event, human factor, part of body, source of injury, and fatality cause, exhibited significant associations with electrical trade fatalities. Fatalities in electrical occupations are attributable to increased exposures to electrical hazards during regular work activities. Strict adherence to safe work practices and procedures is critical to electrical fatality prevention.

Effects of overhead power‐lines on the density of ground‐nesting birds in open sub‐arctic habitats

Yearly electricity production has increased steadily worlwide in recent decades and the associated overhead power lines are widespread and occur across urban and natural habitats, and often in remote areas where there is little other anthropogenic influence. Here we assessed the effects of overhead power lines on the density of ground‐nesting birds in the Icelandic lowlands, which host several populations of international importance. The combined breeding density of the eight study species increased significantly from ~ 112 birds/km2 close (< 50 m) to the power lines to ~ 177 birds/km2 away (450–500 m) from the power lines, with two of these species (Eurasian Whimbrel Numenius phaeopus and Common Redshank Tringa totanus) increasing significantly with distance from power lines and six species (European Golden Plover Pluvialis apricaria, Common Snipe Gallinago gallinago, Meadow Pipit Anthus pratensis, Black‐tailed Godwit Limosa limosa, Dunlin Calidris alpina and Redwing Turdus iliacus) showing no changes. These findings suggest that power lines can influence the breeding density of ground‐nesting bird species in their vicinity and that accounting for such effects when planning future infrastructure will be imperative.

Interpretation of flight data from a fixed-wing UAV system dedicated to flying over high voltage lines

This paper analyzes and presents an interpretation of the flight data resulting from a flight of a fixed-wing UAV system that was designed from the beginning to perform support missions in order to monitor losses on critical infrastructure in Romania; in this particular case it monitors the losses on the high voltage powerlines in order to detect Corona discharge. Also, for the safety of the flight, in order to design the flight route, aspects regarding the altitude, the relief and the possible obstacles that may appear on the flight route were analyzed. After designing the flight route in accordance with the path of a 400 kV high voltage overhead powerlines, the flight was performed and the flight parameters were analyzed in order to validate the system. In conclusion, from the analysis of UAV parameters and its behavior in case of a real flight on high voltage lines it can be stated that UAV systems with fixed wing are recommended for flight on overhead powerlines, behave stably, sensors on board are not influenced by electromagnetic field of the powerline, so that this type of UAV system does not endanger the physical integrity of the overhead powerlines or the system operation.

Wildland fires ignited by avian electrocutions

AbstractUncontrolled wildfires are occurring with increasing frequency across western North America due to a combination of wildfire suppression, climate change, impacts from mountain pine beetles (Dendroctonus ponderosae), alterations in range composition by nonnative grasses, and human population growth in fire‐prone landscapes. A poorly studied mechanism of wildland fire ignitions occurs when a bird perched on an overhead power line is electrocuted, its plumage ignites, and the burning bird falls into and ignites dry vegetation. Avian‐caused ignitions have been occasionally documented, but not spatially analyzed in the contiguous United States. We hypothesized that spatial analyses could demonstrate specific regions where ignitions from avian electrocutions occur most frequently. To test our hypothesis, we compared public reports of wildland fires ignited by bird electrocutions to Environmental Protection Agency ecoregions. We found reports of 44 wildland fires ignited by avian electrocutions in the contiguous U.S. from January 2014 to December 2018. The Mediterranean California ecoregion had the highest density of avian‐caused fires. It would be prudent for electric utilities in the Mediterranean California ecoregion in the U.S., and in fire‐prone landscapes globally, to develop fire mitigation plans that include modifying power poles to reduce risk of avian electrocutions and resulting wildfires.

Fast Algorithm for Contactless Partial Discharge Detection on Remote Gateway Device

Detection of the high impedance fault caused by vegetation is one of the biggest challenges brought by the usage of covered conductors in medium voltage overhead power lines. One of the accompanying events of long-term contact of vegetation with the XLPE insulation is partial discharge which damages the insulation. Current systems for the detection of partial discharge have two major problems: the price and difficult installation. In this paper, an approach for the detection of the partial discharge from the data collected by the antenna is described. This approach is focused on the small computational demand and low false positive rate. Thanks to the small computational requirements, it can be run on the remote gateway devices which are collecting the data from the antenna. It is composed of four steps: outlier detection, outlier clustering, feature extraction, and classification. It is shown that this approach greatly improves the detection rate and lowers false positives compared to the previous algorithm used for partial discharge detection based on the data from an antenna, making it fit to use in the production environment.

Mathematical Model of Single Overhead power Line in Symmetrical operation Mode of Higher Harmonic Switching

Mathematical Model of Single Overhead power Line in Symmetrical operation Mode of Higher Harmonic Switching

Optimal Design of Distribution Overhead Powerlines Using Genetic Algorithms

As the design of distribution overhead power lines becomes increasingly standardized in the 21st century, the reduced search space of its design parameters allows for increasing opportunities to automate the design process. It involves specifying the distribution utility pole heights and classes, pole-top attachments, and conductor span tensions. A successful algorithm must be able of generating designs that are compliant with applicable codes and utility standards, achieve construction labour and material costs that are commensurate to that of a human-created design, and require a reasonable computation time. A design automation algorithm is created for ATCO Electricity, Alberta, Canada. Based on provided requirements and constraints, it uses the genetic algorithm to optimize the design parameters, including a completed design staking list, material loading file, and relevant calculation reports for use by the design department. Evaluation of the developed tool is based on five samples of real design scenarios. Within a reasonable amount of computation time, the tool produces results free from major design errors, comparable in material and construction costs to those of human-created designs. Furthermore, the design automation tool makes rigorous use of design decisions that result in small cost savings but that are not commonly found in human-created designs.

Математическая модель модуля дистанционного мониторинга опор воздушной линии электропередачи по каналу измерения угла наклона опоры

In continuation of previously published results, we are currently building a mathematical model of a remote monitoring module for overhead power line poles by measuring a lean angle. For the purpose of this research, we found input and output variables for the said remote monitoring module and created a model of lean angle dynamics along and across a pole. The results of this research are already being tested by utility companies.

Integrated numerical simulation of an electromagnetic transmission line galloping excitation test system

PurposeThis paper aims to establish the mathematical model and solve the complex calculation multi-field coupling problem for an electromagnetic overhead transmission line galloping excitation test system.Design/methodology/approachAn electromagnetic excitation test system is introduced. To calculate the vibration response of the transmission line, a transient coupled finite element model containing electromagnetic repulsive mechanism and transmission line system was established. Considering the advantages of Newmark-ß algorithm and fourth-order Runge–Kutta algorithm, the two algorithms are combined to solve the model. Compared with the simulation results of existing commercial finite element software, the accuracy of the calculation model of electromagnetic force and wire vibration response are verified.FindingsComparison results show that the proposed calculation model can accurately obtain the force of electromagnetic mechanism and the vibration response of the overhead power lines, and improve the calculation efficiency. The calculation results show that vibration under electromagnetic excitation presents a double half-wave mode, and the galloping amplitude varies according to the charging voltage.Originality/valueThis paper built the transient simulation model for a galloping test system. The Newmark-ß algorithm and the fourth-order Runge–Kutta algorithm are used to solve the model. The research results are of great significance for the actual galloping test system design.

Quantitative analysis of the operational reliability of overhead power lines

The relevance of ensuring the efficiency of equipment, devices and installations (facilities) of electric power systems increases every year, becoming the most important problem of maintaining energy security. The decrease in work efficiency is due to a number of factors, but, above of all, due to an increase in the relative number of objects whose service life exceeds the standard value. An illustration of the methodology for quantifying, comparing and ranking the monthly average values of the operational reliability indicators of 110 kV and higher overhead power lines is given in order to identify and restore the wear of the least reliable lines.

ТЕХНІКО-ЕКОНОМІЧНЕ ОБҐРУНТУВАННЯ ВИБОРУ КОНСТРУКЦІЇ ФАЗИ ТА ПЕРЕРІЗУ ПРОВОДУ ПОВІТРЯНОЇ ЛІНІЇ ЕЛЕКТРОПЕРЕДАЧ

The paper analyzes the existing method of choosing the cross-section of wires by the method of an interval of economic curves. It is shown that the cross-section of the wires and the design parameters of the lines must correspond to the ratio between the cost of construction and the cost of optimizing the design of phase wires. The algorithm of application of this method for 330 kV power transmission lines with split phase is substantiated. A current load search algorithm has been developed and proposed, in which it is assumed to switch to the use of split-phase wires with minimal costs. Many arrays of curves are constructed, which allows for choosing the cross-section of wires and the conditions under which it is necessary to split the phase wire. Algorithms for selecting economically feasible wire cross-sections and methods for determining the conditions of profitability of overhead power lines are presented. The optimization of the cross-section and construction of the line phases was carried out, and the conditions of expedient phase splitting and application of lines of increased natural power were determined. The least-squares method was used to approximate the lower envelope. Ref. 9, fig. 3, table.

Barriers to wildlife movement in straits: Problematizing habitat connectivity across marine ecosystems

The innovative development of the legal regime of straits has prevented the erection of ‘sovereignty-barriers’ to the movement of humans in and above straits. However, it overlooks to a great extent the significance of straits for marine organisms and birds. This article examines if it is necessary to supplement the legal regime of straits with rules that would allow circumnavigating ‘sovereignty-barriers’ also for wildlife movement considering the obligation to protect and preserve the marine environment. The main users of straits are not humans, but rather marine species. They rely on straits for moving from one ecosystem to another. That perspective to straits shifts the emphasis away from anthropocentric connectivity. It raises a question about the need to update the current navigation-oriented legal regime of straits with new wildlife-centric rules. This implies an additional scrutiny on human activities that have a significant negative effect on marine organisms and the fragile marine environment of straits. A wildlife-centred approach enables to reconsider the appropriateness of some human uses of the seas that are environmentally hazardous, but still relatively commonplace in straits. It is possible to facilitate the unimpeded movement of marine species through straits by the prohibition of some detrimental maritime practices that have a reasonable alternative. Such practices include, e.g., the detonation of naval mines in clearance operations, the construction of such causeways that are impassable for marine species, and the use of overhead power lines in straits. In addition, limits could be set to the use of sonars and to the speed of ships in straits.

Impact on the perceived landscape quality through renewable energy infrastructure. A discrete choice experiment in the context of the Swiss energy transition

This paper examines how mixes (wind, photovoltaic, power lines) of different renewable energy infrastructure (REI) impact people's preferences for various landscape types. This does not only involve the visual character but also meanings that are assigned to these landscapes, which together influence the perceived landscape quality. The research is based on a representative online panel survey of Swiss residents (n = 1062). A discrete choice model (15 choice tasks) was implemented to estimate people's preferences for different REI scenarios across several landscape types. Hierarchical Bayes analysis allowed us to determine preferences of the different respondents, while choice simulation allowed us to estimate preferences for every potential scenario (n = 224) of the discrete choice experiment. While the results show a heterogeneous picture of people's preferences, they also reveal common general patterns. Near-natural, mid/high-elevation landscapes in the Alps are clearly rejected for REI implementation. Landscapes dominated by settlements or intensive agricultural use and landscapes in mountain tourist areas are preferably selected for REI developments. REI scenarios including overhead power lines perform consistently lower than scenarios without power lines. Overall, high preferences for scenarios with low REI indicate that society still lacks awareness of the need for massive REI implementation to achieve a sustainable energy transition.

Intelligent Fault Diagnosis Tool For Power Line Systems

The paper focuses on the intelligent fault diagnosis system for automatic analysis of a huge amount of images with 4K resolution collected during flight inspection of the overhead power lines with the use of aerial platforms. The developed system can be used to detect and locate anomalies of power line structures e.g. anomalies of towers, conductors, dampers, insulators, etc. The purpose of the paper is to present the general architecture of the system and the results obtained during inspection of thousands of kilometer flights of power lines. The proposed system is based on the predefined deep neural network called Faster R-CNN which is dedicated for solving real-time object detection problems. The faster R-CNN-based neural model created on COCO dataset was additionally retrained by the authors applying images gathered as a result of flight inspections in order to obtain the high performance of the whole system. The comprehensive verification tests were carried out to prove the merits of the proposed solution.

Sustainable Deep Learning at Grid Edge for Real-Time High Impedance Fault Detection

High impedance faults (HIFs) on overhead power lines are known to cause fires. They are difficult to detect using conventional protection relays because the fault current is insufficient to cause tripping. The delay in detecting HIFs can result in severe bushfires and energy losses; hence a high throughput, low latency detection scheme needs to be developed for HIF detection. Moreover, the complexities associated with HIF detection demands signal processing techniques combined with artificial intelligence to achieve higher detection accuracy. This paper proposes a sustainable deep learning-based approach in an edge device, that can be mounted on top of a power pole to detect HIFs in real-time. Data acquisition, feature extraction, and deep learning based fault identification are performed in an embedded edge node to achieve higher throughput, reduced latency as well as offload the network traffic. Furthermore, optimization techniques such as hardware parallelism and pipelining are adapted to achieve real-time fault identification on edge devices while ensuring the efficient usage of its limited resources. Real-time implementation of the proposed system is validated through laboratory experiments and the results demonstrate the suitability of edge computing to detect HIFs in terms of reduced detection latency (115.2 ms) and higher detection accuracy (98.67 percent).

Application of the Transfer Matrix Approach to Direct Lightning Studies of Overhead Power Lines With Underbuilt Shield Wires—Part I: Theory

This work is devoted to the analysis of voltages produced on overhead distribution lines hit by direct lightning. We will consider arbitrary terminations at both line ends and, also, arbitrary positioning of the pole being struck. We will deal with lines protected by shield wires, placed either above or below the phase conductors. The analytical tools chosen to deal with such complex system are the transfer matrix method and the theory of multiconductor transmission lines with periodic grounding. The innovation of an artificial symmetrical unit cell has been introduced to eliminate the need of two characteristic wave impedance matrices and to ease computation flow.

Интеллектуальная система предотвращения гололедных аварий на воздушных линиях электропередачи сверхвысокого напряжения

Most of the damage on overhead transmission lines happens due to ice accumulation on conductors. This paper is devoted to ice damage prevention on extra high voltage split-phase overhead power lines. The key idea is using high-frequency heat up of wires instead of de-icing with power supply interruption. It is proven that keeping wire temperature at 0 °C is enough for the damage prevention purpose. The authors demonstrate the structure and description of the developed damage prevention system with adaptive control depending on climate conditions.

Application of an Artificial Thunderstorm Cell to Study the Effect of Atmospheric Electricity and Lightning on the Elements Protected by Dielectric Shells in Overhead Power-Line Monitoring Systems

Application of an Artificial Thunderstorm Cell to Study the Effect of Atmospheric Electricity and Lightning on the Elements Protected by Dielectric Shells in Overhead Power-Line Monitoring Systems