Overhead Power Lines Research Articles

Fault Location Method for Overhead Power Line Based on a Multi-Hypothetical Sequential Analysis Using the Armitage Algorithm

The use of modern methods for determining the fault location (FL) on overhead power lines (OHPLs), which have high accuracy and speed, contributes to the reliable operation of power systems. Various physical principles are used in FL devices for OHPLs, as well as various algorithms for calculating the distance to the FL. Some algorithms for FL on OHPLs use emergency mode parameters (EMP); other algorithms use measurement results based on wave methods. Many random factors that determine the magnitude of the error in calculating the distance to the FL affect the operation of FL devices by EMP. Methods based on deterministic procedures used in well-known FL devices for OHPLs do not take into account the influence of random factors, which significantly increases the time to search for the fault. The authors have developed a method of FL on OHPLs based on a multi-hypothetical sequential analysis using the Armitage algorithm. The task of recognizing a faulted section of an OHPL is formulated as a statistical problem. To do this, the inspection area of the OHPL is divided into many sections, followed by the implementation of the procedure for FL. The developed method makes it possible to adapt the distortions of currents and voltages on the emergency mode oscillograms to the conditions for estimating their parameters. The results of the calculations proved that the implementation of the developed method has practically no effect on the speed of the FL algorithm for the OHPL by EMP. This ensures the uniqueness of determining the faulted section of the OHPL under the influence of random factors, which leads to a significant reduction in the inspection area of the OHPL. The application of the developed method in FL devices for OHPLs will ensure the required reliability of power supply to consumers and reduce losses from power outages by minimizing the time to search for a fault.

A Novel Charging Station on Overhead Power Lines for Autonomous Unmanned Drones

Innovative drone-based technologies provide novel techniques to guarantee the safety and quality of power supply and to perform these tasks more efficiently. Electric multirotor drones, which are at the forefront of technology, face significant flight time limitations due to battery capacity and weight constraints that limit their autonomous operation. This paper presents a novel drone charging station that harvests energy from the magnetic field present in power lines to charge the drone’s battery. This approach relies on a charging station that is easy to install by the drone on an overhead AC power line without modifying the electrical infrastructure. This paper analyses the inductive coupling between the energy harvester and the power line, electrical protection, the power electronics required for maximum power point tracking and the mechanical design of the charging station. A drone that perches on a cable, an end effector for installation procedures and the charging maneuver are described, along with discussion of the robotic and electrical tests performed in a relevant environment. Finally, a lightweight drone charging station capable of harvesting 145 W of power from a 600 A line current is reported.

Application of Search Algorithms in Determining of Fault Location on Overhead Power Lines According to the Emergency Mode Parameters

Identification of fault locations (FL) on overhead power lines (OHPL) in the shortest possible time allows to reduce the time for shutting down OHPL in case of damage. This helps to improve the reliability of power systems. FL devices on OHPL according to the emergency mode parameters (EMP) are widely used, as they have a lower cost. However, they have a larger error than FL devices that record traveling wave processes. Most of the well-known algorithms for FL on OHPL by EMP assume a uniform distribution of resistivity along the OHPL. In real conditions, this is not the case. Application of these algorithms in FL devices on OHPL with inhomogeneities leads to significant errors in calculating the distance to the fault location. The authors proposed the use of search algorithms for u-nconstrained one-dimensional optimization to increase the speed of implementation of iterative procedures in FL devices on OHPL by EMP. The authors have developed recommendations for choosing optimization criteria, as well as options for implementing computational procedures. Using the example of a two-sided FL on OHPL, it is shown that the use of search algorithms can significantly (from tens to hundreds of times) reduce the number of steps of the computational iterative procedure. The implementation of search algorithms is possible in the software of typical relay protection and automation terminals, without their hardware upgrade.

Многофакторное автоматизированное исследование методов определения места повреждения на модели воздушной линии электропередачи 500 кВ

Fault location is one of the main means of automation of electric power on overhead power lines. Well-timed elimination and organization of maintenance and repair work to put power lines into operation require high accuracy of fault location. Fault location methods based on the parameters of emergency mode using data of electronic (digital or optical) instrument transformers have been developed in Ivanovo State Power Engineering University (ISPU). The use of electronic transformers makes it possible to reduce the instrumental error of fault location due to accurate measurements of electrical quantities during short circuit, including the measurement of the derivative of the primary current. The aim of the study of fault location methods developed by the ISPU team is to evaluate the errors of these methods with a variation of many factors affecting the calculation of fault location in an automated mode using modern modeling tools. A multifactorial automated research of the fault location methods is carried out using a simulation model of an ultra-high voltage network in the Matlab + Simulink software package. One-sided and two-sided fault location methods based on the parameters of emergency mode developed in ISPU are chosen as the studied methods. In the research methodology presented in the article, the values of the factors affecting the measurement of fault location, including the parameters of the network element models, are changed using a program in the MATLAB language with parallel calculations performed on different processor cores. A technique for automated research of fault location methods has been developed including a model of an ultra-high voltage electrical network in Simulink and a simulation model control program in Matlab. More than 100,000 computational experiments have been carried out for each fault location method. According to the study, the influence of transient resistance is excluded, and the influence of the network frequency is practically absent in the two-sided method. The change in the parameters of power transmission lines and equivalent systems is less affected in comparison with the one-sided method. The Monte Carlo method of fault location algorithms has shown that the errors of one-sided method do not meet the requirements of PJSC «FGC UES» standards in less than 20% of cases, and the errors of the two-sided method under the same modeling conditions do not meet the requirements only in 1% of cases. The developed research methodology makes it possible to evaluate the accuracy of fault location methods when changing the set of factors influencing the measurement in an automated mode. The carried-out research of one-sided and two-sided fault location methods based on emergency mode parameters and data of electronic transformers has showed sufficient accuracy on the model of a 500 kV overhead power transmission line with changes in individual factors affecting the measurement of fault location and when randomly setting a set of parameters of the network model.

Energy Harvesting Device for Smart Monitoring of MV Overhead Power Lines-Theoretical Concept and Experimental Construction.

Modern technological advancements have opened avenues for innovative low-energy sources in construction, with electric field energy harvesting (EFEH) from overhead power lines serving as a prime candidate for empowering intelligent monitoring sensors and vital communication networks. This study delves into this concept, presenting a physical model of an energy harvester device. The prototype was meticulously designed, simulated, constructed, and tested, to validate its foundational mathematical model, with implications for future prototyping endeavors. The findings illustrate the potential of harnessing ample power from this device when deployed on medium-voltage (MV) overhead power lines, facilitating the monitoring of electric and meteorological parameters and their seamless communication through the Internet of Things (IoT) network. The study focused on the medium voltage applications of the harvester. Two dielectric materials were tested in the present experiments: air and polyurethane. The measurement results exhibited satisfactory alignment, particularly with the air dielectric. Nevertheless, deviations arose when employing polyurethane rubber as the dielectric, due to impurities and defects within the material. The feasibility of generating the requisite 0.84 mW output power to drive process electronics, sensors, and IoT communications was established. The novelty of this work rests in its comprehensive approach, cementing the theoretical concept through rigorous experimentation, and emphasizing its application in enhancing the efficacy of overhead power line monitoring.

Characteristics of Wires of the Long-Operated Aluminum-Steel Cable at Different Places on an Overhead Power Line Span

During operation, cables of overhead power lines (OPLs) are exposed to the impact that differs in separate parts of the OPL span due to the different responses of cables near the clamps and far from them. This paper presents the results of a study of aluminum and steel wires cut from such separate parts of ACSR cables before and after exploitation. Structural, microstructural, and elastic–microplastic properties of wires and their changes during operation were studied through optical microscopy, energy-dispersive X-ray microanalysis, electron backscattering diffraction, X-ray diffraction, densitometry, and acoustic measurements. The characteristics of the properties of the wires along the span were found to change in a coordinated manner. Numerical estimates of the influence of the steel core on aging the ACSR cable were obtained. Changes in the properties of the wires, as well as oxidization and corrosion of their near-surface layers, were studied in detail. Quantitative values of the characteristics of properties, the most distant from those observed in the new wires, were revealed for samples of aluminum and steel wires cut from the cable at 1/4 span and near clamps. It is assumed that these cable parts should be the most crucial for cable durability.

Future projections of wet snow frequency and wet snow load on overhead high voltage conductors over Italy

Heavy snowfalls represent some of the most serious hazard for transmission and distribution grids because they trigger the formation of sleeves on overhead power lines whose loads may cause outages and, consequently, prolonged disruptions of the energy supply. In order to provide useful information in planning and decision making to cope with wet snow impacts and strength the resilience of the Italian transmission network, some future climate projections about the occurrences of wet snow events and the related loads on overhead power lines were elaborated for different 20-year periods until 2100 by using 12 high-resolution Euro-CORDEX models (spatial resolution of ∼12 km) under the two different emission pathways RCP8.5 (without mitigation) and RCP4.5 (with moderate reductions of greenhouse gases emission). In addition, the reanalysis dataset MERIDA OI was used to bias-correct the climate models as well as to implement a methodology aimed to estimate climatic wet snow scenarios, by the use of a wet snow accretion model on power lines. The results were validated comparing them with wet snow loads observed at the Vinadio WILD station (Italy) and with the recorded failures in energy supply during some serious wet snow events occurred in Italy. Referring to Extreme Value Analysis, probability maps of wet snow loads exceeding some infrastructural hazard thresholds were estimated by means of the “Generalized Extreme Values” distributions, assuming a stationary climate in each 20-year period. In order not to have to assume climate stationarity, two new frequency indices were calculated directly from the outputs of the models, and the Wilcoxon test was applied to investigate the statistical significant of the trends, as well the agreement among the models to test the robustness of the results. In both methods the results point out relatively complex patterns of climate change effects: wet snow events will generally decrease in frequency and intensity at medium-low altitude, particularly under RCP8.5 pathway where projections highlight a sharply reduction of the events, as rainfalls will prevail over snowfalls due to global warming. But, by the end of the Century, wet snow events are likely to intensify over high Apennine and Alpine regions so far spared because of their historical cold temperatures. Finally, the evolution of wet snow events was investigated and tested more specifically for some mountain sites.

Hybrid Active-Passive Shielding of Magnetic Field of Overhead Power Lines with Triangular Phase Conductors Arrangements

The aim of the work is to design a robust hybrid active-passive magnetic field shielding system created by overhead power lines with a triangular arrangement of phase wires, designed to increase the shielding efficiency of the initial magnetic field in residential premises to the level of sanitary standards and reduce the system's sensitivity to changes in system parameters. To achieve this goal, the following tasks were solved: the structure of a hybrid system of active-passive shielding was developed, and the synthesis of a system consisting of a double-circuit active and multi-circuit passive parts was performed. The synthesis of the system is reduced to solving a vector game, in which the vector payoff is calculated based on the solutions of the Maxwell equations in the quasi-stationary approximation using the COMSOL Multiphysics software. The solution of a multicriteria game is found on the basis of algorithms for optimizing a multi-swarm of particles from Pareto optimal solutions, taking into account binary preference relations. The most important results are theoretical and experimental studies of the effectiveness of the synthesized hybrid active-passive shielding system for the magnetic field created by overhead power lines with a triangular arrangement of phase wires in the shielding zone. The significance of the results obtained lies in the fact that in the course of designing a hybrid active and multiloop passive screens, the parameters of passive and active screens were calculated; as well as practical recommendations are given on the reasonable choice of the spatial arrangement of a multi-loop passive shield and two shielding windings of a robust system of hybrid shielding of the magnetic field created by overhead power lines with a triangular arrangement of phase wires.

Automatic Calculation of Graphic Area Change Rate for Icing Overhead Power Line Insulators Based on Bounding Box Automatic Matching and GrabCut Contour Automatic Segmentation

Image monitoring of icing insulators is valuable for ice-disaster risk management of overhead power lines. This paper proposes an automatic calculation method of graphic area change rate for icing insulators to address laborious manual viewing, computational complexity, poor generalization, weak interpretability, and label data demand of existing approaches. The method automatically identifies insulators in monitoring images by the trained YOLOv5 model, matches the ice-free and test images taken by the same terminal at the same angle utilizing intersection over union of identified bounding boxes, and segments them using an improved GrabCut algorithm. In the segmentation maps, insulator string contours before and after icing are automatically detected to compute the graphic area change rate. The graphic area change rate of insulators in 815 images monitored by 22 terminals from December 2017 to February 2018 is automatically calculated, which is separately data-fused with the tension monitoring value and equivalent ice thickness collected closest to the image acquisition time to obtain the 22 terminals' time series correlations. The correlations approximately follow normal distributions with mathematical expectations of 0.70 and 0.68 and reach 0.95 and 0.94 for high-quality image samples, respectively, verifying the effectiveness. The method enables real-time evaluation of insulators' icing degrees.

Intelligent System of Relay Protection of Electrical Network 6-10 kV with the Implementation of Automatic Correction of the Operation Set Point

The purpose of the study is to develop the architecture and working algorithm of intelligent relay protection of an electrical network with an isolated neutral. “Intellectualization” of relay protection is necessary to increase its sensitivity and reliability. This problem is relevant due to the accident rate of overhead power lines and incorrect operation of traditional relays. This is due to the fact that the set point is not adjusted according to the deviation of the line parameters with changing environmental and load conditions. The purpose of the study is achieved by solving the following problems: the concept of supplementing an electronic relay with a mechanism for correcting the operation set point is proposed. The use of the digital shadow of the electrical network is substantiated. The digital shadow interrogates the sensor system. The advantage of using a digital shadow as part of relay protection has been proven. This allows emulating faults and estimating currents to correct the setpoint. The most significant result of the study is an example of the implementation of intelligent relay protection using a digital shadow in the form of an artificial neural network. The application of a neural network for approximating the current function of a two-phase short circuit is demonstrated. The significance of the results lies in the improvement of the sensitivity and selectivity of current protection due to the digital shadow for working out emergency modes. The convenience of operating and reproducing a digital shadow in the form of a neural network is noted.

The Influence of Orographic Conditions of Terrain on the Methodology for Calculating the Lightning Transmission of Overhead Power Lines

The Influence of Orographic Conditions of Terrain on the Methodology for Calculating the Lightning Transmission of Overhead Power Lines

Improving the efficiency of medium voltage (MV) distribution lines using risk matrix for optimized maintenance

Medium Voltage overhead lines within North-West power utility companies in South Africa are confronted by higher volumes of deficiencies leading to frequent power failures. An essential quality of service factor considered in power distribution is the electricity supply to customers free of interruptions. Due to the higher number of electrical power line faults associated with the power system life span, achieving the desired level of reliability becomes an enormous task. The paper shares the findings of a study on performance improvement of MV distribution overhead lines using a risk matrix for deficiency analysis and clearing of such defects. A pilot study was conducted, and the risk matrix strategy developed in the study improved the reliability and key performance indicators by trimming down the overhead power line deficiencies. Defect clearing lowered outage frequency, durations, and power losses. The System Average Interruption Duration Index (SAIDI) was enhanced by lowering the outage duration by 108.64 h annually. The System Average Interruption Frequency Index (SAIFI) improved by reducing the outage frequency by 45.45 sustained occurrences annually and Reticulation Supply Loss Index (RSLI) by 8.31 MVA monthly.

Efficient unmanned aerial vehicle paths design for post‐disaster damage assessment of overhead transmission lines

AbstractThe widespread distribution of overhead transmission lines increases the vulnerability of power grids to failures. Thus, power lines need to be timely inspected, especially before or during emergency‐related situations to ensure stable operation of the power grid. Traditional methods of visual inspection (satellites and helicopters) are inconvenient, often cannot be deployed and if they are deployed present a slow response time and high cost, which is very critical for fast post‐disaster damage identification. On the other hand, employing an unmanned aerial vehicle (UAV) offers a more efficient, reliable, and faster means for the assessment process. This article proposes a novel approach for the post‐disaster UAV‐based damage assessment of overhead power lines. In the proposed approach, the UAVs paths over the most critical loads are formulated as an optimisation problem with the objective of minimising the total inspection time while considering the recharging of the UAVs' batteries. To solve the problem, an efficient framework that optimises the UAVs flight paths is proposed to inspect the critical loads in an efficient order, while accounting for the UAV recharging. This guarantees that the UAVs complete the assessment tasks unlike existing benchmarks.

Study of changes in leakage currents under a contaminated and moistened surface of insulators of the PS-6B, PS-120A, PSD-70E types of overhead power lines

In the process of operation, insulators are exposed to repeated pollution and atmospheric influences. This is due to the removal of pollutants from industrial metallurgical enterprises, chemical plants and their deposition on the surface of insulators near power transmission lines. In normal operation, when the insulators are dirty, but their surface is not wetted, the active component of the total leakage current can be neglected. It is another matter when the surface of the contaminated insulator is intensively moistened by atmospheric influences, for example: rain, fog, dew, respectively, and the value of the active component of the leakage current also increases in proportion to the conductivity of the formed electrolyte, the layer of contamination on the surface of the insulating surface of the insulator. The article discusses the method of measuring leakage currents on the contaminated surface of various types of glass plate insulators in laboratory conditions, with artificial and natural contamination. In the dry state, a leakage current flows through contaminated insulators, which mainly depends on the electrical capacity of the insulator. A method of calculating the active component of the leakage current is proposed, since the active component of the leakage current is the main parameter for determining energy losses due to its dissipation into the environment. The results of the change in the value of the leakage currents in the time characteristics after wetting the surface layer of pollution to the leakage current in the dry state of the insulator surface are given. The observation of drying processes of a contaminated and moistened surface due to the influence of leakage currents is given. The formation of dried zones on the surface of contaminated insulation of plate insulators of overhead power lines under the action of leakage currents was investigated. An analysis of the obtained results was carried out, conclusions were drawn.

Study of foreign experience in dealing with ice and frost deposits on the wires of overhead power lines

The means and technologies for predicting and preventing frost and ice deposits on the wires of overhead power lines in the power grids of foreign countries are presented. The focus is on such systems as Meteo, dynamic thermal rating, online monitoring of China Southern Power Grid, Variable resistance cable de-icing system and mobile ice melting units. The advantages and disadvantages of these systems are analyzed and it is found that such approaches require energy consumption and are relevant only for the relevant region of the power grid, depending on weather conditions and the distance of electricity transmission. The mechanical, electromechanical, electrothermal, and physicochemical methods of predicting frost and ice deposits on the wires of overhead power lines are considered. It was found that the consideration of dynamic processes is essential and effective in the study of power grids in extreme weather conditions, and the data on frost and ice deposits on overhead line wires are characterized by high dimensionality, nonlinearity, multimodality, and heterogeneity, which makes it impossible to create an accurate forecasting model using traditional methods of evaluation and decision-making. The method of time series analysis and the method of Ensemble Empirical Mode Decomposition are proposed to solve this problem. The basis of these methods is to maximize the use of inherent regularities represented by frequency and time characteristics for effective data analysis and to create the basis for subsequent models and improve their forecasting accuracy. On the basis of the research, the author proposes ways to adapt and integrate the experience of foreign countries into the power grids of Ukraine. The necessity of creating integrated information systems for monitoring meteorological parameters and operating modes of power grids using specialized forecasting models and IT systems is substantiated, which will automate the process of assessing the current state of overhead power lines based on meteorological data in order to timely prevent emergencies in power grids provoked by frost and ice deposits.

Selection of an optimal cable brand for high-voltage overhead power lines based on criterion analysis

This paper is aimed at developing a versatile approach to selecting an optimal cable brand for overhead transmission lines for use in design practice, adapted to conventional and new-generation cable types. To implement multi-criterion evaluation of external factors and limitations when selecting a cable type, the methods of systems, hierarchy and comparative analysis were used. A method for selecting an optimal cable brand based on hierarchy analysis was developed along with an algorithm for its implementation when designing new or modernizing existing overheadlines. The developed approach is demonstrated on the example of construction and modernization of 220 kV overhead lines with the conventional AC cable and such new-generation domestic brands, as АСВТ, АСВП, АСк2у and АСТ. In the considered examples, the technical feasibility of the construction of a new overhead line was limited by the value of the sag. For the modernization project, the specific weight of the cable was of greater importance. The selection criteria included the span length, cable cost and admissible continuous current. The АСВП and АСТ cable brands showed the greatest compliance with the selection criteria (27.5% and 55.9%, respectively). Therefore, at minimum capital investments, the АСВП brand ensures the optimum span length in the construction of a new overhead line, whereas the ACT brand ensures the maximum capacity in the modernization of an existing line. The conducted verification calculations confirmed the feasibility and versatility of the proposed method for selecting a cable brand.

The effects of habitat loss and fragmentation on the relative abundance and conservation of Ludwig’s Bustard Neotis ludwigii in South Africa

Ludwig’s Bustard Neotis ludwigii is near-endemic to the semi-arid shrublands of southwestern southern Africa and is listed as Endangered. The primary threat to this species is collisions with overhead powerlines; however, loss and fragmentation of its habitat may contribute to its population decline. The 1990 and 2020 land-use land-cover (LULC) maps prepared for South Africa were used to determine the LULC categories that best describe suitable habitat for Ludwig’s Bustard using beta regressions and data on exact localities, as recorded in the real-time BirdLasser logging app. Optimized Hot Spot Analysis was used to determine the priority areas for conserving Ludwig’s Bustard and its habitat. Beta regression models were compiled using the reporting rate for this bird and the total surface area of suitable habitat, and three other landscape metrics, calculated using the per pentad LULC categories considered suitable habitat for the bird. These analyses revealed that, between the first and second Southern African Bird Atlas Projects, the distribution range of Ludwig’s Bustard increased by 153 quarter-degree grid cells, whereas the reporting rate for the species declined by 5.6%, along with a small net decline in its quarterdegree-grid-cell-based area of occupancy, its pentad-based area of occupancy and habitat. The habitat of Ludwig’s Bustard is dominated by shrubland with limited grassland, in primarily the Nama Karoo and Succulent Karoo biomes, and the Grassy Karoo Biome in the eastern part of its distribution. In the relative abundance hot spot of Ludwig’s Bustard, there does not currently appear to be any significant loss or fragmentation (distance between patches) of its habitat. A landscape-based approach to conserving Ludwig’s Bustard can be achieved by expanding the current network of protected areas and conserving critical biodiversity areas and ecosystem support areas, especially in the bird’s relative abundance hot spots in the Nama Karoo and Succulent Karoo biomes.

Numerical Analysis of Fretting Wear Characteristics of Aluminum Cable Steel Reinforced Strands

In view of the concealment of the wind vibration of transmission lines and the technical problems that can easily lead to accidents caused by the wear of wires and fittings, overhead power lines are taken as a research object, and the contact and fretting wear characteristics of the transmission lines are studied. The important parameters such as stress during frictional contact, wear morphology and contact surface pressure during frictional wear are analyzed and appropriate conclusions are drawn from them. Taking the LGJ 150/8 transmission line as an example, through the theoretical analysis and calculation of the steel core-aluminum strand model, and according to the parameters of the power grid program, the contact mechanics model of the overhead line under the wind vibration is created using the three-dimensional modeling software. The change in the contact stress between the steel strand and the conductor layer, the change in the micro-displacement and the relationship between stress and vibration frequency are examined. The fretting properties of adjacent conductor contact points are calculated and analyzed, providing a mechanical basis for analyzing the mechanism of wear of overhead lines.

Исследование влияния переходного сопротивления на дистанционное определение места повреждения на основе одностороннего метода

Fault location on 110–220 kV overhead power lines is one of the main functions of modern relay protection devices. Currently, the actual errors of fault location based on emergency mode (EM) parameters in most cases are about 5 %. However, there are cases when they exceed 10–20 %. One-sided fault location based on EM parameters and improvement of its accuracy are important issues to study since there isn’t a communication channel on power lines for the transmission of emergency information everywhere. The main parameter that has a significant impact on the accuracy of fault location method is the transient resistance. The aim of the research is to study the effect of transient resistance on the one-sided fault location method based on EM parameters proposed by A.E. Arzhannikov. In the course of the study, the following tasks are set: assessment of the effect of transient resistance on the accuracy of the specified fault location method; determination of the polarizing value for fault location, which ensures greater accuracy of the method, including the presence of transient resistance at the place of a short circuit; defining a criterion to recognize the type of short circuit that does not depend on the transient resistance; development of a method to determine the value of the transient resistance at the fault location. To study and evaluate the errors of distance fault location based on EM parameters, a series of calculations of short circuit currents has been made for various transient resistances at the fault location and at various distances of the fault. The calculation of currents and data processing has been carried out in the ARM SRZA software package. A single overhead line with a voltage of 110 kV with a two-sided supply and a length of 70 km is chosen as the object under study. To perform the research, the primary converters are taken as ideal. The authors have obtained the estimation of the errors of the one-sided fault location method. It is proposed to use the zero-sequence current as a polarizing quantity in the indicated fault location method, which provides greater accuracy than the use of the negative sequence current. To ensure the stable operation of one-sided fault location based on EM parameters, especially in case of short circuit with significant transient resistances, the use of methods that are insensitive to transient resistances is justified. A parameter to identify the type of short circuit is proposed, the coefficient of the image Kobr. Its values are determined for each type of short circuit, a small dependence on transient resistances is found. A calculation substantiation is given for the value of the identification coefficient of two-phase faults (Phase-to-Phase and Phases-to-Earth) according to the ratio of negative and zero sequence currents. The authors have estimated the transient resistance at the fault site by the ratio of symmetrical components for the simulated power transmission line. The results of the study can be used to improve the existing methods of fault location based on EM parameters, namely: to improve their accuracy considering the transient resistance at the fault site; to improve their accuracy using a suitable polarizing value; to determine the type of short circuit more accurately by using the proposed identification parameter.

Optimization of spatial arrangement of magnetic field sensors of closed loop system of overhead power lines magnetic field active silencing

Aim. Development of a method for optimization of spatial arrangement and angular position of magnetic field sensors of a closed system to ensure maximum efficiency of active silencing canceling of the magnetic field generated by overhead power lines. Methodology. Spatial arrangement and angular position of magnetic field sensors of closed loop system of overhead power lines magnetic field active silencing determined based on binary preference relations of local objective for multi-objective minimax optimization problem, in whith the vector objective function calculated based on Biot–Savart law. The solution of this vector minimax optimization problem calculated based on nonlinear Archimedes algorithm of multi-swarm multi-agent optimization. Results. Results of simulation and experimental research of optimal spatial arrangement and angular position of magnetic field sensors of a closed system to ensure maximum efficiency of active silencing of the magnetic field generated by overhead power lines with a barrel-type arrangement of wires. Originality. The method for optimization of spatial arrangement and angular position of magnetic field sensors of a closed system to ensure maximum efficiency of active shielding of the magnetic field generated by overhead power lines is developed. Practical value. An important practical problem optimization of spatial arrangement and angular position of magnetic field sensors of a closed system to ensure maximum efficiency of active silencing of the magnetic field generated by overhead power lines has been solved.