Global Energy

RAR RUS 5-20 Ahmed Osman B-7916-2013 6601971248 0000-0002-1173-8727 Peter the Great St. Petersburg Polytechnic University, Russia Korovkin Nikolay nikolay.korovkin@gmail.com

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Optimal reactive power dispatch in power system comprising renewable energy sources by means of a multi-objective particle swarm algorithm The electricity grid is developing fast today, with more renewable energy sources (RES) penetrating the industry. The traditional optimal reactive power dispatch (ORPD) is a complex and non-linear optimization problem and one of the sub-problems of the optimal distribution of the power flows in an energy system. The incorporation of RES further exacerbates this complex problem. In this paper, the ORPD problem solved as a single-objective as well as a multi-objective optimization problem in a power system comprising RES. This paper aims to minimize the active power loss and improve voltage profile by introducing renewable energy sources, such as wind and solar sources, in addition to the existing traditional sources. The optimization in a power system is achieved by adjusting control variables, such as generator voltages, tap ratios of a transformer, shunt capacitors, without violating technical constraints that are presented as equalities and inequalities. A multiobjective particle swarm optimization (MOPSO) algorithm is proposed to obtain the optimal values of the control variables of the power system. In the first stage, the modified PSO (MPSO) used to determine the optimal location of RES for IEEE 14 bus and IEEE 30 bus test systems. In the second stage, MPSO and genetic algorithm (GA) were used for individual optimization of objectives, and in the third stage, the objective functions are treated as competing objectives and optimized simultaneously in a single run. Finally, the best compromise solution was extracted from the optimal Pareto set and supplied to the decision-maker by fuzzy set theory. Also, the results of MOPSO are compared to MPSO, GA, and multi-objective GA. 10.18721/JEST.27101 621.316 multi-objective optimization particle swarm optimization photovoltaic panels renewable energy sources wind energy power loss voltage deviation https://engtech.spbstu.ru/article/2021.115.1/ Ahmed%2C-Osman%2C-Korovkin-(na-angl_).pdf

RAR RUS 21-30 Peter the Great St. Petersburg polytechnic university Kalimov Alexander Vazhnov Sergey Govor Vladislav Development of a solenoidal magnet with high uniformity of the magnetic field in the aperture The article discusses an effective procedure for optimizing the shape of the winding and ferromagnetic shield of a solenoid magnet, which is part of the focusing system for a charged particle beam. The main purpose of the study is the formation of a uniform magnetic field in the aperture of a solenoid. The peculiarity of this optimization procedure is its division into several stages. On the first of them, the best distribution of the current density in the winding is determined, which provides the maximum possible extent of the area of uniformity of the magnetic field. At the second stage, a practically realizable structure of the magnet winding is formed, which simulates the optimal current density distribution in the first approximation. At the last stage, amendments are made, allowing the use of the magnet in the mode of both stationary and rapidly changing current in the winding. The external ferromagnetic shield of the magnet selected ensures good quality of the magnetic field in the aperture and negligible power losses at the same time. 10.18721/JEST.27102 621.3.013.22 magnetic field solenoid optimization electron lens ferromagnetic shield https://engtech.spbstu.ru/article/2021.115.2/ Kalimov%2C-Vazhnov%2C-Govor.pdf

RAR RUS 31-40 Popov Aleksey Fedorovich Evgeny Kulakov Egor Denisova Irina Influence of number of electric condensate pumps on feedwater pump operating reliability in the BREST-OD-300 power unit circuit Thermal power plants with a closed-feed cycle. This analysis includes a comparison of the available cavitation reserve of feedwater pumps (FWPs) of operating units with that of BREST-OD-300. We established that the number of electric condensate pumps (ECPs) on closed-feed cycle units is equal to the number of FWPs. A preferable system cycle was selected. We used a dynamic model of the BREST-OD-300 power unit to calculate and analyze the mode with failure of the ECP-2 without switching on the reserve pump. Based on the calculation results, we formulated certain characteristics requirements ECP-2 should meet in case their number agrees with that of FWPs. According to the characteristics obtained from the manufacturers, a calculation was made for the same ECP failure mode with an ECP-and-FWP number ratio equal to one. The use of the dynamic model of a power unit makes it possible to assess the reliability of equipment in modes with equipment failure even before the construction of the plant. Based on the study results, it is clear that the number of ECPs of the BREST-OD-300 unit should be no less than the number of FWPs. 10.18721/JEST.27103 621.311.25.621.039 NPP reliability feedwater pump cavitation reserve closed-feed cycle dynamic model https://engtech.spbstu.ru/article/2021.115.3/ Popov%2C-Fedorovich.pdf

REV RUS 41-50 Morachevski Andrey morachevski@mail.ru Popovich Anatoliy popovicha@mail.ru Progress in researching batteries with potassium The number of studies of rechargeable current sources with potassium and its compounds, such as potassium-ion batteries, potassium-chalcogen (sulfur, selenium) and potassium-oxygen (air) based batteries, has been growing since 2015 and in 2020, it exceeded 350 papers in total. This mini review continues a series of our publications about the development of the studies in the field of rechargeable systems based on alkaline metals and magnesium and considers only the papers published in 2020. As before, due to abundant experimental researches, we primarily considered the reviews and only a few of original w orks. Creation of lithium-ion batteries, their mass production (in 2021, it is the 30th anniversary since the launch of their production) became one of the greatest successes of the modern applied electrochemistry. In 2019, the authors of the pioneering works in this field were awarded the Nobel prize. Nonetheless, because of various requirements to autonomous electric sources (electrochemical parameters, accessibility and cost of materials for their manufacturing, operational safety, etc.), there is a never ending and intent search for new electrode materials and electrolytes for Li-ion batteries, and new electrochemical systems which could compete with the lithium batteries. Modern conferences on current sources provide a separate section: “Beyond Li-ion”. 10.18721/JEST.27104 546.32 rechargeable power supplies potassium-ion batteries potassium-sulfur system potassium-selenium system potassium batteries https://engtech.spbstu.ru/article/2021.115.4/ Morachevskiy%2C-Popovich.pdf

RAR RUS 51-73 Fuks Mihail Frolov Maksim Tcemenko Alina Analysis of the structure, phase composition and mechanical properties of a pipe welded joint made of heat-resistant HP40NBTI alloy The authors studied the microstructure and phase composition of a pipe welded joint made of HP40NbTi alloy based on the Fe-25Cr-35Ni system of an ethylene pyrolysis furnace using light and scanning electron microscopy and energy-dispersive spectroscopy. The short-term mechanical properties at room and elevated temperatures, as well as the long-term strength of the base metal of the pipe and the welded joint are determined. The paper shows that the structural heterogeneity of the weld and the formation of the G-phase in the structure of the HP40NbTi alloy in the thermal influence zone have the following impact: the strength and plastic characteristics of the welded joint are not affected at room temperature; the ductility is slightly reduced at elevated temperatures; the long-term strength is significantly reduced at operating temperatures of pyrolysis plants. The paper investigates the nature of the fracture of the base metal and the welded joint. The results reveal the role of the G-phase in the formation of cracks during the operation of the w elded joint made of the HP40NbTi alloy. 10.18721/JEST.27105 669.017.15:669.018.44:620.18:621.791.051 heat-resistant austenitic alloys welded joint microstructure phase composition G-phase mechanical properties https://engtech.spbstu.ru/article/2021.115.5/ Fuks%2C-Frolov%2C-Tsemenko.pdf

RAR RUS 74-86 Zaytsev Igor' Blokhin Aleksandr Strengthening of epoxy resins with carbon nanomaterials The paper studies the current state of the art in the field of creating composites based on epoxy matrices with carbon nanomaterials. These composites are considered major competitors to many traditional structural materials. The article studies carbon nanomaterials such as graphene, graphene oxide,carbon nanotubes, which can improve the physical and mechanical or operational characteristics of composite materials. Methods of their introduction into a polymer matrix are considered and way oriented to industrial production are selected, and comparative results of improving the strength characteristics of the obtained nanocomposites are presented. The improvement of the physical and mechanical properties of a polymer composite material with a filler in the form of modified carbon nanotubes has been investigated. The best sample containing 0.1 mass. % of fluorinated CNTs in the composite showed an increase in tensile strength by 48%. 10.18721/JEST.27106 669-539.5 composite polymer epoxy resin carbon nanotubes strength https://engtech.spbstu.ru/article/2021.115.6/ Zaytsev%2C-Blohin.pdf

PER RUS 87-88 . In memory of professor Mikhail Romanovich Petrichenko . . . . https://engtech.spbstu.ru/article/2021.115.7/ Hronika-(Petrichenko-M_R_).pdf