Global Energy

RAR RUS 5-16 6603036819 Peter the Great St. Petersburg Polytechnic University, Russia Titkov Vassiliy titkovprof@yandex.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Kolychev Aleksandr Gulov Aleksandr THE EFFECT OF A GROUNDED WIRE ON THE MAGNETIC COMPONENT OF INDUCED OVERVOLTAGES OF OVERHEAD TRANSMISSION POWER LINES In the electric grids of the Russian Federation, the reliable operation of distribution grids with a voltage of 6–35 kV is attracting more and more attention. Their operation is under significant influence of lightning overvoltages associated with a direct lightning strike into the line, and induced overvoltages when lightning strikes the ground near the overhead line. The lightning overvoltages affecting the 6–35 kV overhead lines lead to an increase in their accident rate during operation due to the relatively low impulse electric strength of the linear insulation of the lines. Cable protection against lightning overvoltages is not used for the 6–35 kV overhead lines in the Russian Federation. As calculations show, the installation of a grounded cable on overhead lines due to the coefficients of the connection between the cable and the wire reduces the magnitude of the induced overvoltages. The paper presents a mathematical model for calculating the electromagnetic component of an induced overvoltage based on an approach that uses the wave equation of a line with a voltage source distributed along its length, created by an EMF induced by lightning current in the presence of a grounded wire on 35 kV power lines. The issues of inductive overvoltage arising during repeated lightning discharges, which can lead to large amplitudes of the magnetic inductive component of overvoltages in comparison with the main discharge of the lightning current, are investigated. The electrostatic component of induced overvoltages has lower values during repeated lightning discharges, since the discharge occurs through a partially ionized channel, in which the leader stage of the discharge is characterized by lower electric field strengths. It is shown that the use of a grounded wire with distributed conductivity on a 35 kV overhead line causes a potential on the wire, which at steep fronts of the lightning current is close to 50% of the value of the magnetic component of the induced voltage on the phase wire. 10.18721/JEST.27301 621.315.1 Induced overvoltage magnetic component of overvoltage repeated return lightning strikes overhead line with grounded wire; lightning protection https://engtech.spbstu.ru/article/2021.117.1/ Titkov%2C-Kolichev%2C-Gulov.pdf

RAR RUS 17-26 Astafiev Georgiy Voloshin Kirill 6603036819 Peter the Great St. Petersburg Polytechnic University, Russia Titkov Vassiliy titkovprof@yandex.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

IMPROVING THE CHARACTERISTICS OF ELECTROSTATIC POWER SUPLY SYSTEM OF PERMANENT LIGHT MARKING OF OVERHEAD POWER LINES Gas-discharge lamp and electrostatic antenna are important elements of the system of permanent light marking of 35–110 kV overhead power lines. The paper considers the possibility of using electrostatic antennas of irregular shape to increase the luminous intensity of gas-discharge lamps. It is shown that the frame antennas under the conditions of limiting the maximum size allow higher operating current and brightness of the gas-discharge lamp than in case of a standard rectilinear antenna. To estimate the electrical capacity of the irregularly shaped antennas made of a thin circular cross-section profile, the authors applied the method of an integral equation of the first kind with respect to the distribution of the linear charge density on the structural elements. Using the COMSOL Compiler and MATLAB Compiler tools, the authors developed application software, which allows geometric parameters input, antenna design visualization, and calculation of the electrical capacitance. The spatial displacements of irregularly shaped antennas under the influence of wind loads are estimated. 10.18721/JEST.27302 621.327 overhead power line light marker gas-discharge lamp electric capacity integral equation calculations rectilinear antenna frame antenna wind loads https://engtech.spbstu.ru/article/2021.117.2/ Astafev%2C-Voloshin%2C-Titkov.pdf

RAR RUS 27-38 Krivosheev Sergey ksi.mgd@rambler.ru Kolodkin Ivan Magazinov Sergey Ochkovskaya Julia Reznikova Anastasiya WAVE PROCESSES MODELING IN THE VERTICAL GROUNDING ELECTRODE UNDER LIGHTNING IMPACT The paper presents the results of testing grounding devices (GD) of power lines under impulse impact. The modeling of current spreading in vertical electrodes of various lengths in soils with different electrophysical parameters in the wave formulation of a coupled electromagnetic field is carried out. On the basis of the results obtained, the main factors affecting the formation of wave processes of a vertical ground electrode were determined: in soils with high dielectric permittivity and/or specific resistance, wave processes are observed better; an increase in the length of the electrode leads to a decrease in the frequency of oscillations of the ground electrode current in the homogeneous soil. The observed wave processes can affect the transient impedance of the GD and the effectiveness of lightning protection using, for example, non-linear surge arresters. 10.18721/JEST.27303 621.3.053.1 grounding device impedance transient characteristics lightning impact lightning protection https://engtech.spbstu.ru/article/2021.117.3/ Krivosheev.pdf

RAR RUS 39-49 Kolobov Vitaliy Barannik Maksim Ivonin Viktor EXPERIENCE OF OPERATING A CONDITION MONITORING SYSTEM FOR METAL-OXIDE SURGE ARRESTERS The paper presents a low-cost system for monitoring the condition of metal-oxide surge arresters (MOSAs) in service. The developed system integrates two methods currently used for evaluating the condition of surge arresters: registration of transient overvoltages experienced by a MOSA and analysis of leakage current. The system includes a set of sensors, a surge counters equipped with leakage current sensors (SCLCS), and one measuring unit. The SCLCS measures the current pulse charge, performs threshold selection of pulses, and registers the date and time. The registration data is stored in non-volatile memory. A measurement module connected successively to each SCLCS reads the registered data and also performs a comprehensive analysis of the MOSA leakage current: it identifies the resistive component of the total current; determines the phase angle between the voltage applied to the surge arrester and the first harmonic of the leakage current; performs a harmonic analysis of the leakage current. The voltage of one of the phases of a substation potential transformer is used as a reference signal, which is received via the radio channel from the transmitting unit of the system. The developed system for monitoring the condition of metal-oxide surge arresters was installed at several distribution substations. Long-term pilot operation of the system has shown that a comprehensive analysis of the leakage current allows not only to identify the deterioration of the technical condition of the MOSA, but also to determine the causes of degradation of the characteristics of the protective device. Data obtained by a SCLCS provides useful information on lightning and switching transient overvoltages arising in a particular network segment, the efficiency of the arrester operation, and the amount of energy absorbed by the MOSA. The paper describes the hardware implementation, operational principles, and main technical specifications of the proposed system. The results of the pilot testing of the system are presented. 10.18721/JEST.27304 621.311 metal oxide surge arrester; condition monitoring; surge counter; discharge currents; the charge of surge current; leakage current analysis https://engtech.spbstu.ru/article/2021.117.4/ Kolobov%2C-Barannik%2C-Ivonin.pdf

RAR RUS 50-62 Vysogorets Svetlana visogorecsp@komienergo.ru Redkin Sergey Zhitenev Mikhail SEARCH OF MODERN ENGINEERING SOLUTIONS FOR AUTOMATIC CONTROL OF TRANSFORMER INSULATION TECHNICAL STATE The paper outlines the problems of transformer insulation operation as well as assesses the influence of moisture on dielectric characteristics of insulation, the rate of oxidation processes in oil and thermal aging of insulation. The influence of moisture content on the service life and load capacity of transformers is shown. A comparative analysis of traditional methods of solid insulation and liquid dielectric drying is carried out. We confirmed the need to develop online methods for insulation drying of operating transformers and formulated basic requirements for automatically controlled moisture management systems of transformer equipment. The British technology “TRANSEC” was modified on the basis of these requirements. The paper presents results of trial installations of improved automatically controlled moisture monitoring and management system on several operating transformers. We determined the scope of application for moisture management system. Introduction of such systems will improve reliability and operation efficiency of power transformers. 10.18721/JEST.27305 621.314.212 transformer insulation moisture automated system condition management https://engtech.spbstu.ru/article/2021.117.5/ Visogorets%2C-Redkin%2C-Zhitenev.pdf

RAR RUS 63-76 Poliakov Valeriy ONLINE DIAGNOSTICS OF THE ACTIVE PART OF POWER TRANSFORMERS The paper describes a method for obtaining the characteristics of the active part of power transformers online. The method is based on the processing of digital current and voltage wave-forms obtained at turning on of unloaded transformer with premagnetized core. The core of transformer, switched off by a circuit breaker, has residual induction value closing to nominal Bn = 1.5. Switching on of the transformer leads to addition of working AC field to residual one. Therefore full magnetic field may achieves saturation induction B = 3 T. In this case winding cur-rent is close to shorting one Idemag = (5-6)In. It let's to build magnetization curve – dependence of the magnetic flux on winding current. This dependence let's to get all the parameters of the active part of the transformers, which are usually measured on a disconnected transformer using an external voltage source. 10.18721/JEST.27306 621.317.33 Power transformer magnet circuit waveform unloaded mode demagnetization saturation induction magnetization curve active part parameters https://engtech.spbstu.ru/article/2021.117.6/ Polyakov.pdf

RAR RUS 77-85 Tadzhibaev Aleksei Draganchev Hristo Yarovoy Viktor Gayurov Lutfullo Korkin Leonid FORECASTING OF THE TECHNICAL CONDITION OF ROLLING BEARINGS BASED ON VIBRATION ANALYSIS The paper describes the results of research in the framework of creating a production asset management system by the example of determining the resource indicators of rolling bearings of electric motors. Mathematical models to predict the technical condition of rolling bearings In the frame of the research have been developed. The possibilities to take into account the factors of secondary impact on the bearing assembly showed on the example of coupling defects. The problem of choosing the frequency of control is solved, which consists in meeting the requirement that the bearing does not reach the maximum technical condition by the time of the next control. Two methods of assigning periodicity according to the rate of damage development are considered. The equations that take into account the stages of running-in, normal operation and increased wear at the maximum operating time are justified. The developed method of forecasting the technical condition allows to organize operation on the basis of technical condition management systems. The implementation of such systems ensures the minimization of the accident rate of bearing units and the increase of the reliability of electric motors. 10.18721/JEST.27307 620.178.53:621.313 rolling bearings electric motor frequency of monitoring wear and tear forecasting of the technical condition https://engtech.spbstu.ru/article/2021.117.7/ Tadzhibaev%2C-Yarovoy%2C-Gayurov%2C-Korkin.pdf

RAR RUS 86-96 Povolotskaya Anna Zadvorkin Sergey Putilova Evgeniya Mushnikov Aleksandr PECULIARITIES OF MAGNETIC BEHAVIOR OF LOW-ALLOY STRUCTURAL STEEL SPECIMENS UNDER ELASTIC DEFORMATION AFTER PRELIMINARY CYCLIC LOADING The paper shows results of studying the effect of zero-to-tension cyclic loading with an amplitude approximately corresponding to the conventional yield strength, and subsequent static elastic tension along the same direction on the magnetic behavior of low-alloy structural 08G2B steel. Magnetic characteristics were measured both in a closed magnetic circuit and with the use of attached transducers along and across the direction of the applied loading. The cyclic prehistory affects the magnetic behavior of the material during its subsequent elastic deformation since preliminary cyclic loading induces various compressive residual stresses along the direction of the loading. The study reveals the range of applied tensile stresses in which the magnetic characteristics measured on the specimens cyclically pretensioned with different numbers of cycles vary unambiguously. Thus, these parameters have potential application in the development of methods for evaluating stresses in 08G2B steel products in view of their history. Cyclic loading elastic tension magnetostriction coercive force attached transducer https://engtech.spbstu.ru/article/2021.117.8/ Povolotskaya.pdf

RAR RUS 97-108 Monastyrskiy Aleksandr MODERN SYSTEMS FOR MONITORING THE TECHNICAL CONDITION OF POWER OIL-FILLED TRANSFORMERS Continuous monitoring systems for power equipment have become more and more widespread in recent years, due to a number of reasons. First of all, this is determined by a significant aging of the power equipment park, which leads to a decrease in its operational reliability. Indeed, to maintain the required reliability, “old” equipment requires much more attention and especially a significant reduction in the period of its monitoring. The digitalization of the industry plays a significant role in this process. Digitalization is impossible without the use of the latest technologies, which include continuous monitoring of equipment. In addition, digitalization implies a reduction in the human factor in operation based on the wider use of computer technology. To the greatest extent, all this applies to transformer equipment. Systems for continuous monitoring of transformer equipment began to be used in the late 80s and by now, considerable experience has been accumulated in their development and operation. The paper analyses the basic principles of constructing systems for continuous monitoring of power transformers of higher voltage classes, shows the need to use them, especially for transformers with a long service life, defines the requirements for these systems, gives the parameters that need to be monitored by these systems. As an example of a continuous monitoring system, the authors describe SKIT system developed at Peter the Great St. Petersburg Polytechnic University. SKIT has been introduced and is being commercialized at a number of energy facilities. 10.18721/JEST.27309 621.314 continuous monitoring power transformers construction principles required para-meters basic requirements for systems https://engtech.spbstu.ru/article/2021.117.9/ Monastirskiy.pdf

RAR RUS 109-119 Makhmutov Tagir Razumov Nikolay n.razumov@inbox.ru Popovich Anatoliy popovicha@mail.ru DEVELOPMENT OF SYNTHESIS METHOD FOR SINGLE-PHASE HIGH-ENTROPY CERAMIC MATERIALS WITH A HIGH DEGREE OF CHEMICAL HOMOGENEITY ON THE EXAMPLE OF EQUIATOMIC HIGH-ENTROPY CARBIDE (TIZRHFTANB)C The paper presents the synthesis results of high-entropy carbides using pre-mechanically alloyed powders of high-entropy alloys (HEA). The use of HEA as a starting material for synthesizing high-entropy ceramics allows obtaining one-phase and chemically homogeneous high-entropy carbides due to preliminary mixing of metals at the atomic level, accompanied by the formation of a single-phase solid solution. We showed that in the process of sintering a mechanical mixture of pre-mechanically alloyed HEA powders with graphite at temperatures of about 1600°C, high-entropy carbide with the chemical formula MeC and space group Fm-3m is formed. However, according to the phase composition and microstructure analysis, inclusions are formed in the form of zirconium-hafnium oxide and a transition layer between oxide inclusions and the main carbide phase. Raising the temperature up to 2000°C produces a single-phase and chemically homogeneous high-entropy carbide (TiZrHfTaNb)C. 10.18721/JEST.27310 669.017: 621.762.2:621.926 high-entropy alloys ceramics carbides mechanical alloying spark plasma sintering https://engtech.spbstu.ru/article/2021.117.10/ Mahmutov%2C-Razumov%2C-Popovich.pdf

RAR RUS 120-133 JSC "Atomproekt" Rogozhkin Vladimir Gorynin Vladimir z1dehy97@mail.wplus.net A-9655-2014 7007045735 0000-0001-7385-147X Peter the Great St. Petersburg Polytechnic University, Russia Kondrat'ev Sergey petroprom2013@yandex.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Mischin Evgeniy B. Kolenov Evgeniy V. COOLER AGAINST OVERHEATING OF EUROPE The paper proposes a principle and presents a Land Coolers aerothermal system (cooler) for the correction of abnormal warming (of the climate) of the European regions. The cooler generates high-altitude technogenic clouds over problem areas using atmospheric moisture in the waters of the near seas, excessive thermal energy consumption of thermal and nuclear power plants, and the prevailing flow of high-altitude tropospheric winds. The cirrus-type umbrella cloud generated by the aerothermal cooler into the troposphere weakens the solar load and overheating of the problem areas of Europe. For high-altitude clouds over 6 km, the system employs a vertical steam-air jet from a coastal energy facility modified by an injector. It forms optically dense clouds of the upper and middle tier of the troposphere with an area of up to 100 thousand square kilometers, protecting the surface air from overheating and ensuring the territories of Europe are covered by Atlantic rains. 10.18721/JEST.27311 551.583 Land Coolers aerothermal system (cooler); regional correction of abnormal warming (climate); high-altitude technogenic cloud cover of the cirrus type; troposphere; thermal energy saving; heat-saving power plants; atmospheric moisture of the sea area https://engtech.spbstu.ru/article/2021.117.11/ Rogozhkin.pdf

RAR RUS 134-144 Strelnikova Angelina Skotnikova Margarita INVESTIGATION OF THE EFFECT OF HIGH-TEMPERATURE DEFORMATION ON THE PROPERTIES OF THE α- AND β-PHASES OF TITANIUM ALLOY The article studies the influence of the high-temperature deformation on phase composition and physico-mechanical properties of the titanium alloy. Research into the topic allows increasing durability, reliability, and the resource of machines and equipment. Materials and designs of machines and equipment are constantly getting upgraded in the world, therefore, it is very important not only to use already known methods of materials research, but also to develop and improve research methods and techniques. In this scientific project, a two-phase titanium alloy 3M was investigated at different degrees of high-temperature deformation (80%, 83%, 86%, 90%, 93%). The authors carried out phase studies using the methods of optical metallography and instrumental indentation. The relationships between the structural-phase state, physical and mechanical properties of titanium alloy 3M with a change in the degree of deformation have been established. The study of the phase composition, properties of the α- and β-phase by the method of indentation of samples with different degrees of hot deformation of the 3M alloy made it clear that with an increase in the degree of deformation, the fraction of the α-phase in the alloy increases, and the material becomes harder and less plastic. 10.18721/JEST.27312 669 titanium alloy high-temperature deformation mechanical properties phase composi-tion optical microscopy instrumental indentation https://engtech.spbstu.ru/article/2021.117.12/ Strelnikova%2C-Skotnikova.pdf