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E-Journal N3(59)2023

"PROBLEMS of the REGIONAL ENERGETICS (https://doi.org/10.52254/1857-0070.2023.3-59)"

CONTENTS

1	Hybrid Active-Passive Shielding of Magnetic Field of Overhead Power Lines with Triangular Phase Conductors Arrangements Authors: Kuznetsov B.I., Kutsenko A.S., Nikitina T.B., Bovdui I.V., Chunikhin K.V., Dobrodeyev P.N. Anatolii Pidhornyi Institute of Mechanical Engineering Problems of the National Academy of Sciences of Ukraine Kharkiv, Ukraine
	Abstract: 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.
	Keywords: overhead power lines, triangular arrangement of phase conductors, magnetic field, robust hybrid active-passive shielding system, theoretical and experimental studies. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.01
2	Intelligent System of Relay Protection of Electrical Network 6-10 kV with the Implementation of Automatic Correction of the Operation Set Point Authors: Shilin A.A., Dement’ev S.S., Dikarev P.V. Volgograd State Technical University Volgograd, Russian Federation
	Abstract: 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.
	Keywords: power supply reliability, relay protection and automation, digital shadows, artificial neural networks, adaptive systems, smart grid. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.02
3	Reduction of Overvoltages under Connection on a High-Voltage Cable Line Due to Optimal Controlled Switching Authors: Lobodzinskiy V., Buryk N., Spinul L., Chibelis V., Illina О. National technical university of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” Kyiv, Ukraine
	Abstract: The purpose of the work is to develop a mathematical model of a cable transmission line, which allows modeling and choosing the optimal conditions for controlled switching to limit overvoltage at the development and design stage. The goal is achieved by solving the problem of determining the initial angle of each phase, so that each phase has an initial switching angle equal to zero with a time delay. A high-voltage cable line for a voltage of 330 kV, implemented using Matlab, has been chosen as the object of study. The most significant result is the method of numerical simulation of the cable line that allows you to analyze transients when each phase of a three-phase cable line is connected to a three-phase source with a time delay, the switching angle of all phases is zero. This, in turn, makes it possible to limit switching overvoltages. The significance of the results obtained lies in the possibility of the proposed technique to choose the optimal conditions for controlled switching, which makes it possible to use it in the design of switching nodes, as well as the use of controlled switching to eliminate unwanted electrical transients during planned switching. The simulation results showed that the greatest effect of using numerical simulation is when each phase of a three-phase cable line is connected to a three-phase source with a time delay of 1/150 second, then the switching angle of all phases is zero, which makes it possible to limit switching overvoltages.
	Keywords: three-phase cable line, switching overvoltage, transient processes, controlled switching, theory of multipoles, modeling of electrical engineering objects. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.03
4	Reduction of High-Voltage Cable Line Capacity Caused by Implementation of Magnetic Field Shielding Techniques Authors: Grinchenko V. 1, Tkachenko O. 2 1 General Energy Institute of National Academy of Sciences of Ukraine, Kyiv, Ukraine 2 Anatolii Pidhornyi Institute of Mechanical Engineering Problems of the National Academy of Sciences of Ukraine, Kharkiv, Ukraine
	Abstract: The paper deals with a capacity of high-voltage cable line made of three single-core cross-linked polyethylene insulated power cables. We consider three cases. First is a single-point bonded cable system when no magnetic field shielding technique is implemented and the capacity achieves maximum values. Second is a solidly bonded cable system when a thermal effect of induced shield currents causes a capacity reduction. The third case under study is a single-point bonded cable system covered by the passive loop. The passive loop mitigates the cable line magnetic field as well as the solidly bonding does, but also the thermal effect of passive loop currents reduces the capacity. The goal of the paper is to evaluate the relative change of cable line capacity when implementing magnetic field shielding techniques comparably to unshielded case. To achieve the goal we use a standard IEC 60287 when calculating the cable line capacity in the first and the second cases, and we use a thermal field simulation when the passive loop is used. Iterations are stopped when the conductor temperature reaches the maximum operating temperature. We show that the increase in cable spacing does not guarantee the capacity increase when the solid bonding of cable shields or the passive loop is used. The most significant result is the substantiation of the advantages of passive loop, which provides the greater cable line capacity in comparison with solid bonding at equivalent magnetic field shielding efficiencies. The obtained results can be used when choosing the type of bonding and the technique of cable line magnetic field mitigation.
	Keywords: cable line, capacity, magnetic field, shielding, passive loop, bonding. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.04
5	Reduction of Voltage Fluctuations in Electrical Networks Supplying Motors with a Rapidly Changing Load by Installing Longitudinal Compensation Batteries Authors: Basmanov V.G., Kalinina E.A., Cherepanov V. V. Vyatka State University Kirov, Russian Federation
	Abstract: The article deals with the reduction of voltage fluctuations in electrical networks of industrial enterprises with the help of longitudinal compensation batteries. The purpose of the article is to develop a method for calculating the optimal parameters of the longitudinal compensation instal-lation, which makes it possible to perform calculations using numerical characteristics of the range of changes in the voltage and flicker dose. To achieve this goal, it is necessary to solve the following tasks: to develop a method for selecting the parameters of reducing voltage fluctua-tions, taking into account the random nature of the change in the parameters of network modes; using the proposed method, to develop a calculation method that allows choosing optimal pa-rameters of capacitor units. The most significant result is the experimental and theoretical con-firmation that the proposed method for selecting the parameters of longitudinal compensation batteries, taking into account the random nature of the change in the flicker dose, makes it pos-sible to effectively apply longitudinal compensation to reduce voltage fluctuations in electrical networks of industrial enterprises with a rapidly changing load. The significance of the results is proved by the fact that the proposed method makes it possible to select a longitudinal compensa-tion installation to limit voltage fluctuations at the design stage, thereby ensuring the quality of electric energy in networks with consumers having a rapidly changing load. The resulting calcu-lation method is planned to be used in distribution electrical networks when performing tech-nical measures to ensure the quality of electrical energy.
	Keywords: asynchronous motors, rapidly changing load, voltage swing, flicker dose, active power, reactive power, longitudinal compensation installation. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.05
6	Study of the Efficiency of Heat-Supply Systems with Steam Turbine CHP Plants, Taking into Account Changes in the Temperature of the Delivery Water during Transportation Authors: Suvorov D.M., Tatarinova N.V., Lyskova E.A. Vyatka State University Kirov, Russian Federation
	Abstract: The aim of the work is to study the efficiency of steam turbine CHPPs in heat-supply systems, taking into account changes in the temperature of delivery water during transportation for vari-ous initial and extended heating regulation schedules. To achieve this goal, the following tasks were solved: calculation of the dependences of the delivery water cooling in the supply and re-turn pipelines on the air temperature, construction of temperature and flow rate schedules of de-livery water adjusted for heat losses during transportation, calculation of energy efficiency indi-cators for the operation of a model CHPP with various options for correcting schedules of deliv-ery water. The most significant results are the following. Firstly, for the first time the method of the degree-by-degree calculation of heat losses during transportation and their distribution be-tween pipelines of heating networks was used. Secondly, the dependences of the delivery water cooling in these pipelines on the outside air temperature are calculated. Thirdly, it has been es-tablished that the specific reference fuel consumption for electricity supply significantly de-creases when switching to more efficient temperature schedules for heating regulation, but changes slightly when switching from natural regulation by flow rate to regulation by the tem-perature of the delivery water. The significance of the obtained results lies in the possibility of their use for an accurate assessment of the efficiency of heat supply systems with different heat-ing control schedules and for determining the feasibility of correcting temperature schedules in order to take into account the cooling of delivery water during transportation.
	Keywords: heat-supply system, heating load, heat-transfer agent transportation, temperature schedule, CHPP, delivery water cooling. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.06
7	The Method of Selecting Boiler Houses under Technical Re-Equipment in a Mini-CHP Authors: Myshkina L.S., Frolova Y.A., Ivanova E.M. Novosibirsk State Technical University Novosibirsk, Russian Federation
	Abstract: The development of the energy sector is aimed at improving the energy efficiency of heat and electricity. One way is to use cogeneration technologies. A large number of boiler houses created the preconditions for the creation of a mini-CHPP through their technical re-equipment. The purpose of the work is to develop a methodology for selecting and ranking boiler houses for transformation into a mini-CHPP. To achieve the goal, the following tasks were solved: the ef-fects of the formation of a mini-CHP in the energy district were revealed; a system of criteria has been developed that determines the feasibility of transforming a boiler house; a ranking co-efficient was proposed that reflects the potential for improving efficiency; the methodology was tested. The difference of the work is the complexity of the methodology, which takes into ac-count both the advantages of cogeneration technologies and energy balances, as well as individ-ual features of each boiler house. Multi-criteria selection of boiler houses is based on the pur-pose, fuel used, heat output and functions in heat supply systems. The technical condition, pro-spective balances of production and consumption of electricity in the energy district of a mini-CHPP are taken into account. The significance of the results lies in the fact that the proposed methodology makes it possible to increase the validity of decisions when transforming a boiler house into a mini-CHPP. The use of the selection results will lead to an increase in the economic efficiency of the heat supply system.
	Keywords: cogeneration, mini-CHPP, energy efficiency, boiler house transformation, distributed energy, efficiency, reliability, environmental friendliness, economy. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.07
8	Methodology for Determining Heat Losses through Translucent Construction Authors: Malyarenko V.1, Alyokhina S.2, Orlova N.3 1O.M. Beketov National University of Urban Economy in Kharkiv, Kharkiv, Ukraine 2University of Applied Sciences Technikum Wien, Vienna, Austria, 3Anatoly Pidhorny Institute of Mechanical Engineering Problems of the National Academy of Sciences of Ukraine, Kharkiv, Ukraine
	Abstract: The purpose of this work is to determine the heat transfer coefficient of translucent fences, considering the number of storeys of buildings, climatic factors, such as wind velocity and outdoor temperature. To achieve this goal, the following tasks were solved: analysis of heat transfer in translucent enclosures as a quasi-stationary process; analysis of heat transfer processes in translucent barriers, which are a combination of solid transparent plates and air gaps connected by a frame structure; determination of the heat transfer coefficient on the glass surface depending on climatic factors and the radiant component. The most important result is the empirical dependence of the heat transfer coefficient on the outer surface of the window block on the Reynolds criterion, the dependences for determining the heat transfer coefficient of window blocks are improved, considering climatic parameters. The heat transfer coefficient of the window block as a whole is presented in the form of analytical ratios, considering the location of the building and its height, changes in wind velocity and outdoor temperature. This methodology was tested on the example of a civil administrative building, for which the heat transfer coefficients of window structures of non-standard series were evaluated. The significance of the research results lies in the possibility of using the obtained dependencies to assess the thermal characteristics of window structures of non-standard shapes. The dependences of the heat transfer coefficient on wind speed and outside air temperature given in the paper can be used in the energy audit of buildings.
	Keywords: heat losses, heat transfer coefficient, Nusselt number, Grashof number, window, wind, external disturbances. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.08
9	Energy-Efficient Modes of Dehydration of Pome Fruits during Microwave Treatment in Combination with Convection Authors: Popescu V., Vișanu V., Balan M., Melenciuc M., Volconovici O., Balan T. Technical University of Moldova Chisinau, Republic of Moldova
	Abstract: The aim of the work is to significantly increase the efficiency of the dehydrating process of fruits with seeds, by treating it with microwaves in combination with convection. To achieve the purpose, an electrical installation was designed, produced, tested, optimized and implemented, which applies the combined technological treatment method in the dehydration process. Pears were selected as the object of the research in particular, because currently the production of these seeded fruits is not fully exploited, but they are of an increased interest for the agricultural producers and for specialized enterprises, and their dehydration by the methods currently used is difficult, especially because of the browning effect that occurs in the heat treatment process. The essential results obtained based on the research carried out, regarding the application of the elaborated installation, are: reduction of electricity consumption and treatment duration, increase in productivity and quality of dehydrated fruits. At the same time, the developed installation is simple in construction, has low cost and is easy to use, and during fruit processing it allows strict monitoring of the technological parameters, and researches demonstrated a high level of safety in operation. The significance of the obtained results lies in the solution to a series of problems, which are currently faced by the enterprises specialized in fruit processing, in particular by significantly increasing the efficiency of the process of dehydration of pears, based on the proposed method of combined treatment, predominantly with increasing the speed of dehydration, energy efficiency, quality of final products and profitability.
	Keywords: electrical installation, dehydration process, fruit with seeds, energy efficiency, microwave, convection. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.09
10	Development of a New Approach to the Problem of Detecting the Integrity Violations of a Digital Image Authors: Bobok I., Kobozeva A. Odesа Polytechnic National University Odesa, Ukraine
	Abstract: The energy sector is an integral part of the critical infrastructure of any state and is particularly sensitive to the quality of information security systems. Due to the diversity of activities of vari-ous organizations in the energy industry, almost all threats to information security are relevant to them, in particular, unauthorized changes in information content. The aim of the work is to de-velop the new approach to the examination of the integrity of images, which will provide the possibility of building universal methods for detecting its violations, effective regardless of the strength and type of influences that change them. The aim was achieved by: introducing the concept of “frequency index” for the singular vector of the image matrix, and study of the properties of the dependence of the frequency index of a singular vector on its number. The most important result of the work is the almost constant rate of increase the trend of the studied function, which results in the linearity of the frequency index of singular vectors for digital im-ages, the integrity of which is not violated. This characteristic is sensitive to any changes in the image matrix. The significance of the obtained result lies in the fact that the use of the estab-lished properties for the function of the dependence of the frequency index of singular vectors on its number makes it possible to develop universal integrity examination methods that are ef-fective regardless of the strength and type of disturbances that violated the integrity of the im-age.
	Keywords: digital image, integrity violation, singular vector, frequency index, sensitivity. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.10
11	Congestion Management Using an Optimized Deep Convolution Neural Network in Deregulated Environment Authors: Dhanadeepika B.1, Vanithasri M.2, Chakravarthi M. 1,2Annamalai University, India, Tamil Nadu 3Vasavi College of Engineering, Telangana, India.
	Abstract: The technical issue of congestion, which is predominantly found in deregulated power systems, is caused by the failure of transmission networks to satisfy load power demands. This failure is primarily caused due to an increase in loads or loss of transmission lines or generators in modern restructured power networks. This work introduces a CM approach using Deep Convolution Neural Network (DCNN) for minimizing congestion and supporting Independent System Operators (ISOs). The purpose of the work is to generate enhanced prediction outputs for congestion management with reduced error values. These objectives were achieved through the actual power rescheduling of generators. The proposed work adopts DCNN which is optimized using an Improved Lion Algorithm (LA) and aids in providing significant outcomes for congestion management with reduced error. By implementing customized IEEE 57-bus, IEEE 30-bus, and IEEE 118-bus test systems, the suggested approach has been successfully verified for its performance on test systems of varied sizes. This analysis incorporates restrictions such as line loads, bus voltage influence, generator, line limits, etc. The most important results for the test system indicating convergence profile, congestion cost, and change in real-power and voltage magnitude are obtained by the simulation in MATLAB, and on the basis of the obtained simulation outcomes, it is evident that the proposed Improved Lion Algorithm optimized Deep Convolution Neural Network displays phenomenal computation performance in minimizing congestion losses at minimum congestion costs. When compared to several contemporary optimization techniques, the suggested technique performs better in terms of congestion cost and losses by generating improved prediction outputs with reduced errors.
	Keywords: congestion management, DCNN, ISO, improved Lion Algorithm, deregulated power. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.11
12	The Method for Generating a Set of Reference Images for Assessing the Condition of Critical Infrastructure Facilities Using Mobile Robots Authors: Tymochko O.1, Burdin M.2, Najafli E.2, Tsukan O.2, Olizarenko S.1, Biryukov I.3, Biriukov О.4, Tiurina V.5, Zakirov S.6, Padalka I.1 1Flight Academy of National Aviation University, Kropyvnytskyi, Ukraine 2Kharkiv National University of Internal Affairs, Kharkiv, Ukraine 3National Academy of the National Guard of Ukraine, Kharkiv, Ukraine 4Kyiv Institute of the National Guard of Ukraine, Kyiv, Ukraine 5Kharkiv National Air Force University named after Ivan Kozhedub , Kharkiv, Ukraine 6Research Institute of Military Intelligence, Kyiv, Ukraine
	Abstract: The purpose of this work is to improve the accuracy of critical infrastructure condition assessment using mobile robots by considering the geometric distortions of the current images during the formation of a set of reference images. The goal is achieved by determining the sampling step values by angles and sighting height without loss of accuracy. The most important result is the determination of acceptable discretization values in the range of angles and heights of a correlation-extreme navigation system. The significance of the obtained results is in solving the problem of forming a set of reference images, which will reduce the impact of changes in the geometry of sighting on the accuracy of the evaluation of objects. A special feature of the results obtained is the establishment of maximum permissible sampling steps in angles and heights of sight to ensure the required accuracy of object state estimation. When forming a set of reference images, the sampling step by height should be (0.06....0.11)% and (0.12....0.2)% relative to the initial flight altitude for the sighting surface with normal and high object saturation, respectively. The angular sampling step is 10...17 degrees and 6...10 degrees, respectively, for the same surface types. The difference from known works is that the perspective and scale distortions are considered at the stage of formation of a set of reference images, which ensures high accuracy of the system functioning in conditions of orientation and sighting geometry changes.
	Keywords: mobile robot, critical infrastructure object, set of reference images, correlation-extremal navigation system, discretization by angles and height. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.12
13	Studies of the Change in the Time Constants of the Discharge of the Capacitor to Predict the Residual life of the Operation of the Electric Motor Authors: Kryvonosov V., Matviienko A. National University of Bioresources and Nature Management of Ukraine, Kyiv, Ukraine
	Abstract: Forecasting the resource of the electric motor makes it possible to increase the reliability of the operation of the electrical complex. The aim of the work is to study the possibility of using changes in the capacitor discharge time constants under conditions of local reactive power compensation as a criterion parameter for predicting the life of an electric motor. To achieve this goal, the following tasks were solved: an analysis of methods for predicting the resource of an electric motor was carried out, a differential equation was analyzed, and relationships between the insulation resistance and the capacitor discharge time constants were established. The most important result is the establishment of the relationship between the state of the insulation and the value of the time constant of the discharge of the capacitor. The most significant result is that the change in the time constant of the discharge is used as a criterion parameter for predicting the resource of the electric motor. The significance of the study is that the value obtained after the first shutdown of the electric motor is taken as the base value of the discharge time constant. The limiting values of the discharge time constants make it possible to estimate the resource of the electric motor after each shutdown. A method and a device for monitoring open-phase network modes are proposed, and when disconnected, control the value of the insulation resistance of the electric motor and predict the residual life of the electric motor.
	Keywords: motor winding insulation, prediction, residual life, reactive power compensation, damping time constant. DOI: https://doi.org/10.52254/1857-0070.2023.3-59.13