Global Energy

MIS RUS 7-15 Jiang H. Proton exchange membrane fuel cells . . https://engtech.spbstu.ru/article/2023.125.1/ Hetsin-Tszyan.pdf

RAR RUS 24-30 Busarov Sergei S. Kobilskiy Roman DESIGN OF PISTON SEALS WITH INCREASED SERVICE LIFE FOR LUBRICATION-FREE LOW-FLOW LOW-SPEED RECIPROCATING COMPRESSORS OF MEDIUM AND HIGH PRESSURE Within the research devoted to improving the workflow of lubrication-free low-flow low-speed long-stroke piston compressors of medium and high pressure, we carried out experimental studies, which made it possible to substantiate the minimum number of cuff seals used to ensure a feed rate of at least 70%. To create an energy efficient machine, the required number of seals is seven. We analyzed the increase in the service life of cuff seals, which made it possible to give practical recommendations for the design of low-speed reciprocating compressors. Thus, to provide a service life of 100,000 hours, fourteen cuffs are needed: their gradual wear also provides a service life with the required level of feed rate. A further increase in the service life is possible with an increase in the number of seals, but this would increase the dimensions of the compressor stage as well. 10.18721/JEST.29301 621.512.2 low-speed compressor service life lip seals feed rate workflow efficiency https://engtech.spbstu.ru/article/2023.125.2/ Busarov%2C-Kobilskiy.pdf

RAR RUS 31-42 Gulov Aleksandr Kolychev Aleksandr OVERHEAD LINE TOWER MODEL IN TASKS OF LIGHTNING PROTECTION A lightning strike at the top of the tower results in dangerous overvoltages, which can lead to back flashover from the tower to the phase wire. Back flashovers are one of the reasons for the transmission line outage. Therefore, various models of overhead line tower have been developed and continue to be developed to analyze transient processes in the tower during lightning overvoltages. Several tower models were compared to calculate the lightning protection of a double-circuit 110 kV overhead line. In Russia, the most common tower model is a set of inductances, while foreign countries employ tower models from surge impedances: the article compares both models. Curves of critical lightning current for several types of tower models are calculated for 110 kV overhead line in EMTP-ATP. The tower footing resistance varies to study the effect of voltage drop at the tower. 10.18721/JEST.29302 621.315.1 transmission line lightning protection tower model overvoltages tower footing resistance https://engtech.spbstu.ru/article/2023.125.3/ Gulov%2C-Kolichev.pdf

RAR RUS 43-56 Zavalov Artem Kuzmin Ilya Kulikovsky Valery INFLUENCE OF REACTIVE POWER COMPENSATION ON THERMAL STABILITY OF NEUTRAL WIRE IN LOW VOLTAGE CITY NETWORKS The use of modern single-phase household electrical appliances and office equipment leads to significant reactive power consumption by power consumers of cities. Unbalanced load by phases in urban four- and five-wire electrical networks up to 1000 V creates conditions for thermal destruction of neutral wire due to the flow of currents close in value or exceeding currents in phases. To justify a rational reactive power compensation system, it is necessary to analyze the electrical consumption of urban power consumers. To confirm the relevance of current reducing task in neutral wire of network, it is necessary to analyze accident rate of urban electrical networks up to 1000 V. Solution to the problem of eliminating conditions for thermal destruction of neutral wire can be the reconstruction of urban cable lines in order to replace them with lines with a large neutral wire section. However, this solution is very labor intensive and expensive. The purpose of this study is to determine whether it is possible to reduce current in neutral wire to acceptable continuous values using effective reactive power compensation. 10.18721/JEST.29303 621.316.727 uneven and unbalanced load neutral wire burnout reactive power compensation computer simulation Matlab/Simulink urban power supply systems https://engtech.spbstu.ru/article/2023.125.4/ Zavalov%2C-Kuzmin%2C-Kulikovskiy.pdf

RAR RUS 57-73 Zavalov Artem Kuzmin Sergey Kuzmin Roman Menshikov Vitalii REACTIVE POWER COMPENSATION IN ELECTRICAL NETWORKS OF 0.4–10 KV IN CITIES OF NORTHERN REGIONS This article substantiates the urgent need for reactive power compensation in power supply systems of cities located in the northern regions of Russia. For this purpose, power consumption of 30 consumers of Dudinka city was studied using power quality analyzer (PKK-57). It was established that the measured power factor for some consumers exceeded the calculated values specified in regulatory documents. The consumers’ total harmonic distortion of voltage was within limits of values normalized by state standard. Total harmonic distortion of current can exceed 30% and have a negative impact on efficiency and failure rate of capacitor units designed to compensate for reactive power. Consumption of active and reactive power in one of the phases of network may differ from the consumption in others by 5.6 and 7.6 times, respectively. The article proposes a method for complex compensation of reactive power in urban power supply systems based on low-voltage capacitor units. According to the proposed method, in networks up to 1000 V, independent individual phase compensation is carried out at inputs of multistory residential and municipal buildings, while in networks of 6–10 kV, compensation is carried out using capacitor units connected through a power transformer of 6(10)/0.4 kV at the low side of the winding. 10.18721/JEST.29304 621.316.727 urban power supply systems power losses reactive power compensation power factor power quality higher harmonics https://engtech.spbstu.ru/article/2023.125.5/ Zavalov%2C-Kuzmin%2C-Kuzmin%2C-Menshikov-(1).pdf

REP RUS 74-89 Mannanov E. Kostelov Andrey Filin A. Zheleznyak Vladimir IMPROVEMENT OF OPERATIONAL RELIABILITY OF AIR-COOLED TURBOGENERATORS FOR A GAS TURBINE PLANT Modern mobile power plants driven by gas turbines traditionally use air-cooled turbogenerators, the levels of operational impacts of which are quit high. The system of electrical insulation of stator windings is a structural element that largely determines the reliable operation of turbogenerators, especially those with air cooling, taking into account the coupled impact of increased thermal, mechanical and electrical loads. An urgent task is to ensure high reliability of such turbogenerators. JSC Power Machines used the technology of vacuum pressure impregnation of the stator (Global VPI) for the production of air-cooled turbogenerators with a capacity of up to 225 MW. However, this technical solution cannot be viewed as successful, since during operation, a number of generators manufactured in recent years had malfunctions that led to unscheduled repairs. The production of a line of air-cooled turbogenerators, including a new turbogenerator for the GTE-170 project, was transferred to the technology of pre-impregnated tapes (Resin Rich). Such a transfer made it possible to ensure a commensurate level of influencing temperatures, modernize the system of slot seals and corona protection layers based on the use of elastic radial and lateral sealing of the rod in the slot. The existing problems of discharge activity, thermomechanical displacements and maintainability of stators were solved, which makes it possible to predict an increase in the operational reliability of such turbogenerators. In the design of the turbogenerator insulation system for the Resin Rich technology, only domestic materials were used, which is an important advantage in the current conditions. 10.18721/JEST.29305 62-1/-9 electrical insulating material stator winding thermal conductivity insulating system reliability https://engtech.spbstu.ru/article/2023.125.6/ Mannanov%2C-Kostelov%2C-Filin%2C-Zheleznyak.pdf

RAR RUS 90-99 Erutin Danil Popovich Anatoliy popovicha@mail.ru Sufiiarov Vadim EFFECT OF SCANNING ANGLE ON THE DENSITY OF 1CP/COPPER SELECTIVE LASER MELTED COMPOSITE MATERIAL In this work, results of the investigation of selective laser melted samples of a mixture of 1CP and copper powders with varying scanning angle are presented. The initial powder material was formed by mixing 1CP iron alloy powder and 10 wt% pure copper powder. The samples of the composite material were obtained using a selective laser melting setup with a varying scanning angle. Macrostructure, phase composition and amorphization degree data of the samples were obtained using optical microscopy, X-Ray diffraction analysis and differential scanning calorimetry. The investigation results can be used for further research and development of the technology of soft-magnetic composites manufacturing via selective laser melting. 10.18721/JEST.29306 621.762 Selective laser melting amorphous phase soft-magnetic alloy scanning strategy additive manufacturing https://engtech.spbstu.ru/article/2023.125.7/ Erutin%2C-Popovich%2C-Sufiyarov.pdf

RAR RUS 100-110 Lavrentev Alekseii Kakorin Daniil Barchukov Dmitry HIGH-PERFORMANCE METHOD OF MANUFACTURING A BIMETALLIC DISC KNIFE The article describes the designs of disc knives for cutting various materials, discusses the known designs and methods of production of disc knives, their advantages and disadvantages. Solid knives made of tool steel are expensive to manufacture and do not allow efficient use of the material. It is advisable to manufacture disk knives of bimetallic design. A method of manufacturing a disc knife is proposed, including the assembly of a package of blanks with subsequent batch surfacing. The surfacing provides a working layer of tool steel. Heat treatment and grinding of work pieces on a cylindrical surface is carried out in a package. The package is divided into individual products using laser cutting. The paper provides a review of several published works devoted to the study of the structure and properties of tool steels after laser exposure. The developed method is protected by a patent of the Russian Federation. 10.18721/JEST.29307 621.715.2, 66.040.2 disc knife bimetal surfacing heat treatment laser cutting package of work pieces https://engtech.spbstu.ru/article/2023.125.8/ Lavrentev%2C-Kakorin%2C-Barchukov.pdf

RAR RUS 111-123 Trotsky Mikhail Popovich Anatoliy popovicha@mail.ru Kaminskii Vladimir Petrovich Sergey lmpa2010@mail.ru DEVELOPMENT OF TECHNOLOGICAL FUNDAMENTALS FOR PRODUCTION OF MULTICOMPONENT COMPOUNDS BASED ON TITANIUM NITROBORIDES (TI3B2N) BY MECHANOCHEMICAL SYNTHESIS AND SPS This work is devoted to the synthesis of titanium nitroborides by mechanochemical synthesis followed by spark plasma sintering (SPS) and plasma spheroidization. The obtained materials did not meet the requirements of the grain size composition for further plasma spraying and use as wear-resistant sprayed coatings. To consolidate the particles, spray drying of the material was carried out. The absence of the stoichiometric composition of Ti3B2N after 20 hours of mechanical treatment of the TiN – TiB2 mixture indicates that either the time or the energy saturation of the process for synthesis is insufficient. However, if we use metallic titanium (Ti), boron nitride (BN) and titanium diboride (TiB2) instead of the above binary compounds as initial components, the processing time can be reduced to 5 hours: this period already produces a compound with the stoichiometry close to the required one. The range of hardness values for the obtained compounds after SPS is from 16800 to 22560 MPa, 19570 MPa on average. 10.18721/JEST.29308 621.762 mechanosynthesis wear-resistant coatings corrosion-resistant coatings ceramic materials titanium nitroboride SPS plasma spheroidization spray drying https://engtech.spbstu.ru/article/2023.125.9/ Trotskiy%2C-Popovich%2C-Kaminskiy%2C-Petrovich.pdf

RAR RUS 124-133 Evsin Mark RHEOLOGICAL AND TRIBOLOGICAL PROPERTIES OF GRAPHENE FLUORIDE MODIFIED LUBRICATING COMPOSITIONS The article studies the influence of graphene fluoride on the structure and properties of greases by optical microscopy, rotational viscometry and tribometry. The tribological properties of the basic and modified lubricating compositions were evaluated using a four-ball friction tester according to the main indicators: the average diameter of the wear spot, the load-wear index, the critical load and the welding load. Rheological studies showed that the introduction of graphene fluoride into the studied basic lubricating compositions increased their viscosity properties and had a positive effect on the strength of the frame structure of the thickener. The study of the microstructure of the samples showed that graphene fluoride is an active component of the system and participates in the process of structure formation of greases. Tests showed an improvement in the tribological properties of modified lubricating compositions. The prospects of using graphene fluoride as a friction modifier for greases was confirmed. 10.18721/JEST.29309 621.89.017 Graphene fluoride grease rotary viscometer four-ball friction tester https://engtech.spbstu.ru/article/2023.125.10/ Evsin.pdf