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Showing records 2476 to 2500 of 41325. [First] Page: 96 97 98 99 100 101 102 103 104 Last
Active Power Filters and Power Quality
Marcin Maciążek
April 27, 2023 (v1)
The transmission of electricity from the source to the load is mainly carried out using a three-phase line [...]
Characteristics of Natural Background Radiation in the Lubin Mine, Poland
Agata Walencik-Łata, Katarzyna Szkliniarz, Jan Kisiel, Kinga Polaczek-Grelik, Karol Jędrzejczak, Marcin Kasztelan, Jacek Szabelski, Jerzy Orzechowski, Przemysław Tokarski, Włodzimierz Marszał, Marika Przybylak, Lech Stolecki, Tomasz Selerowicz, Krzysztof Fuławka
April 27, 2023 (v1)
Subject: Other
Keywords: natural radiation, radioisotopes concentration, underground research laboratory
There has been growing interest in using underground locations for applications in various fields, including research. In Poland, for several years, attempts have been made to build an underground laboratory. For this purpose, selecting an appropriate location requires a detailed analysis of the level of natural radioactivity. The present study presents detailed characteristics of the natural background radiation in close vicinity to shaft L-VI of the Lubin mine, at the depth of 910 m (2275 m w.e.). The in situ measurement of the photon flux in the 7−3150 keV energy range was equal to 8.08 ± 0.90 cm−2s−1, and the gamma-ray dose rate of 0.070 ± 0.010 µSv/h with the highest contribution from 40K and 214B isotopes. The thermal neutron flux measured using helium counters was equal to 4.2 ± 0.9 × 10−6 cm−2s−1. The radon concentration in the air measured with the RAD7 monitor showed low values ranging from 0 to 15.3 Bq/m3. Laboratory measurements of rocks using alpha and gamma spectrometry t... [more]
Study on the Impact of Clean Power Investment on Regional High-Quality Economic Development in China
Xianrong Zhuang, Lingying Pan
April 27, 2023 (v1)
Keywords: clean power investment, high-quality development, spatial Durbin model
In 2017, the 19th CPC National Congress proposed to “establish a sound economic system of green, low-carbon and circular development”, which indicates the direction of high-quality economic development in the new era of China. Clean power investment is a powerful way to promote high-quality economic development by adopting non-fossil-energy utilization and low-emission technologies, as well as creating new jobs. Meanwhile, large-scale investment and a long investment return period result in negative effects on local economies. To better understand the effect of clean power investment, this paper selects panel data of thirty provinces in China from 2010 to 2019 to establish a spatial Durbin model to explore the impact of clean power investment on regional high-quality economic development. The results show that inter-regional high-quality economic development shows significant spatial auto-correlation characteristics. Clean power investment has not only a positive direct effect on high-... [more]
Hydrogen Production by Immobilized Rhodopseudomonas sp. Cells in Calcium Alginate Beads
Eleftherios Touloupakis, Angeliki Chatziathanasiou, Demetrios F. Ghanotakis, Pietro Carlozzi, Isabella Pecorini
April 27, 2023 (v1)
Keywords: calcium alginate, hydrogen production, photobioreactor, photofermentation, Rhodopseudomonas sp.
The present investigation concerns the potentiality of Rhodopseudomonas sp. cells to produce clean energy such as molecular hydrogen (H2). The abovementioned goal could be reached by improving the capability of purple non-sulfur bacteria to produce H2 via a photofermentative process through the enzyme nitrogenase. Rhodopseudomonas sp. cells were immobilized in calcium alginate gel beads and cultured in a cylindrical photobioreactor at a working volume of 0.22 L. The semi-continuous process, which lasted for 11 days, was interspersed with the washing of the beads with the aim of increasing the H2 production rate. The maximum H2 production rate reached 5.25 ± 0.93 mL/h with a total output of 505 mL. The productivity was 40.9 μL (of H2)/mg (of cells)/h or 10.2 mL (of H2)/L (of culture)/h with a light conversion efficiency of 1.20%.
On the Kinetic Mechanisms of the Reduction and Oxidation Reactions of Iron Oxide/Iron Pellets for a Hydrogen Storage Process
Bernd Gamisch, Lea Huber, Matthias Gaderer, Belal Dawoud
April 27, 2023 (v1)
Keywords: iron/iron oxide redox reactions, reaction kinetics, shrinking-core model, thermochemical hydrogen storage
This work aims at investigating the kinetic mechanisms of the reduction/oxidation (redox) reactions of iron oxide/iron pellets under different operating conditions. The reaction principle is the basis of a thermochemical hydrogen storage system. To simulate the charging phase, a single pellet consisting of iron oxide (90% Fe2O3, 10% stabilising cement) is reduced with different hydrogen (H2) concentrations at temperatures between 600 and 800 °C. The discharge phase is initiated by the oxidation of the previously reduced pellet by water vapour (H2O) at different concentrations in the same temperature range. In both reactions, nitrogen (N2) is used as a carrier gas. The redox reactions have been experimentally measured in a thermogravimetric analyser (TGA) at a flow rate of 250 mL/min. An extensive literature review has been conducted on the existing reactions’ kinetic mechanisms along with their applicability to describe the obtained results. It turned out that the measured ki... [more]
Orderliness in Mining 4.0
Sergey Zhironkin, Magerram Gasanov, Yulia Suslova
April 27, 2023 (v1)
Keywords: Data Mining, disorder, Industry 4.0, Industry 5.0, Mining 4.0, Mining 5.0, orderliness
Mining of minerals is an important part of the technical sciences, for which the certainty and unambiguity of terms and the correct application of definitions is an absolute requirement. At the same time, the expansion of Industry 4.0 technologies, both in practice and in scientific discussions, brings new terms to mining that are far from the original meaning. These terms include Data Mining and Mining 4.0, which, having a common digital core, refer to fundamentally different areas of human activity, and have the opposite meaning in relation to the use of resources (digital ones—endless, and the natural ones—finite). The indiscriminate use of the term “mining” is especially dangerous in the context of Mining 4.0, in which digital technologies allow the intensification of the exploitation of natural resources. This brief Perspective paper will show the role of terminology in Mining 4.0 and offer an interpretation of its relationship with Data Mining.
Seismic Description of Deep Strike-Slip Fault Damage Zone by Steerable Pyramid Method in the Sichuan Basin, China
Qingsong Tang, Shuhang Tang, Bing Luo, Xin Luo, Liang Feng, Siyao Li, Guanghui Wu
April 27, 2023 (v1)
Subject: Materials
Keywords: carbonate exploitation, fault damage zone, fractured reservoir, Sichuan Basin, steerable pyramid processing, strike-slip fault
Large quantities of gas resources have been found in the Paleo-Mesozoic carbonate rocks in the Sichuan Basin. However, many wells cannot obtain high production in deep low porosity-permeability reservoirs. For this contribution, we provide a steerable pyramid method for identifying the fault damage zone in the Kaijiang−Liangping platform margin, which is infeasible by conventional seismic methods. The results show that steerable pyramid processing could enhance the seismic fault imaging and a series of NW-trending strike-slip faults are found along the trend of the carbonate platform margin. The steerable pyramid attribute presents distinct vertical and horizontal boundaries of the fault damage zone, and heterogeneous intensity of an un-through-going damage zone. The width of the fault damage zone is generally varied in the range of 100−500 m, and could be increased to more than 1000 m in the fault overlap zone, intersection area, and fault tips. Further, the fault damage zone plays a... [more]
Investigation of Effects of Different High Voltage Types on Dielectric Strength of Insulating Liquids
Fatih Atalar, Aysel Ersoy, Pawel Rozga
April 27, 2023 (v1)
Subject: Materials
Keywords: breakdown voltage, dielectric liquid, electrical stress, partial discharge, transformer
Liquid dielectrics are different from each other, but are used to perform the same tasks in high-voltage electrical equipment, especially transformers. In similar conditions, the insulation performance of transformer oils under different types of voltage will provide dielectric resistance. In this study, three different dielectric liquids applied in transformers, namely mineral oil, natural ester and synthetic ester, were tested. Tests under AC and negative DC voltage were performed at electrode gaps of 2.5 mm, 2 mm and 1 mm using disk and VDE type electrodes as per ASTM D1816-84A and ASTM D877-87 standards, respectively. In turn, the impulse voltage tests were performed under an electrode configuration suggested by the IEC 60897 standard. The current data of 500 ms prior to breakdown under AC electrical field stress was decomposed using the empirical mode decomposition (EMD) and variational mode decomposition (VMD) methods. These analyses were conducted before the full electrical brea... [more]
Thermo-Economic Performance Analysis of a Novel Organic Flash Rankine Cycle Using R600/R245fa Mixtures
Guangbiao Fu, Songyuan Zhang, Zhong Ge, Jian Li, Jian Xu, Jianbin Xie, Zhiyong Xie, Dong Yao, Tao Zhao, Zhijie Wang, Shuaikun Yue, Siyu Zhao, Fanhan Liu, Qiuping Jiang
April 27, 2023 (v1)
Keywords: economics, exergy analysis, mixed working fluid, organic flash cycle, thermal performance
The organic flash cycle (OFC) is a novel power cycle with small exergy loss in the endothermic process. However, the low-pressure throttle valve in the cycle has a large throttling loss. Aiming to reduce the cycle exergy loss and improve the system performance, this study constructs a new configuration named the organic flash Rankine cycle (OFRC). Using the R600/R245fa mixture as the circulating working fluid and 200 °C geothermal water as the heat source, the effects of the change in working fluid composition on the thermal properties of the OFRC were studied based on the first and second laws of thermodynamics. Then, the economic performance of the proposed OFRC was investigated and then compared with that of the conventional OFC. The results show that the OFRC system has a significant improvement in thermal performance and economy compared with the OFC system. When the mole composition of the R600/R245fa mixture is 0.5/0.5, the net output work, thermal efficiency, and exergy efficie... [more]
Application Characteristics of Zeolite-Based Stuffing for Nanofluidic Packer Rubber
Yafei Zhang, Jingwei Liang, Rui Luo, Shiwei Min, Yihua Dou
April 27, 2023 (v1)
Subject: Materials
Keywords: deformation capacity, nanofluidic stuffing, packer rubber, pressure threshold, zeolite
Aiming at obtaining the application characteristics of more nanofluidic stuffing to enrich the database of nanofluidic packer rubber, three zeolite-based nanofluidic types of stuffing with water, glycerin, and a saturated aqueous solution of KCl (hereinafter referred to as saturated KCl solution) as the functional liquids were studied using experiments. The results showed that all the three zeolite-based nanofluidic stuffing types could be applied as stuffing for nanofluidic packer rubber. The setting pressure ranges for zeolite/water, zeolite/glycerin, and zeolite/saturated KCl solution stuffing were 21.71 to 30.62 MPa, 15.31 to 23.57 MPa, and 27.50 to 38.83 MPa, and the specific deformation quantities of the three stuffing types were 72.76, 102.07, and 77.54 mm3∙g−1, respectively. In zeolite/saturated KCl solution stuffing, the number of liquid molecules retained in the nanochannels was the minimum; thus, this stuffing type was the most stable during application. The order of the equ... [more]
Energy Security of Hydropower Producing Countries—The Cases of Tajikistan and Kyrgyzstan
Katarzyna Kosowska, Piotr Kosowski
April 27, 2023 (v1)
Subject: Energy Policy
Keywords: Central Asia, electricity, Energy, energy security, hydropower, Kyrgyzstan, Tajikistan
Energy security, as one of the most important components of state security, is a permanent element of academic debates and political discussions. Owing to the multidimensional and multifaceted nature of energy security, defining it is a complex process, requiring the consideration of a wide range of factors straddling economics, geology, ecology and geopolitics which decide whether we are dealing with the state of energy security or the lack of it. Energy security is usually equated with the security of supply. Another group of definitions of energy security focuses on the concept of security of services. A different approach to energy security issues is presented by energy exporting countries, whose objective is to ensure sufficiently high and stable income from sales of energy resource exports (security of demand). The subject of this paper is an analysis of the energy security of hydropower-producing countries—Tajikistan and Kyrgyzstan. Energy security has been analyzed in the conte... [more]
Influence of Standard Image Processing of 3D X-ray Microscopy on Morphology, Topology and Effective Properties
Romain Guibert, Marfa Nazarova, Marco Voltolini, Thibaud Beretta, Gerald Debenest, Patrice Creux
April 27, 2023 (v1)
Subject: Other
Keywords: computed micro-X-ray microscopy, digital rock physics, effective properties, image processing, pore scale, porous media, segmentation
Estimating porous media properties is a vital component of geosciences and the physics of porous media. Until now, imaging techniques have focused on methodologies to match image-derived flows or geomechanical parameters with experimentally identified values. Less emphasis has been placed on the compromise between image processing techniques and the consequences on topological and morphological characteristics and on computed properties such as permeability. The effects of some of the most popular image processing techniques (filtering and segmentation) available in open source on 3D X-ray Microscopy (micro-XRM) images are qualitatively and quantitatively discussed. We observe the impacts of various filters such as erosion-dilation and compare the efficiency of Otsu’s method of thresholding and the machine-learning-based software Ilastik for segmentation.
Comparison of LID and Electrical Injection Regeneration of PERC and Al-BSF Solar Cells from a Cz-Si Ingot
Siqi Ding, Chen Yang, Cheng Qin, Bin Ai, Xiaopu Sun, Jianghai Yang, Quan Liu, Xueqin Liang
April 27, 2023 (v1)
Subject: Materials
Keywords: boron–oxygen defects, Czochralski silicon, iron–boron pairs, light-induced degradation (LID), passivated emitter and rear cell (PERC), regeneration, solar cell
In order to study the effect of device structures and silicon wafer positions on light-induced degradation (LID) and regeneration, five groups of industrial PERC and Al-BSF solar cells were fabricated by using silicon wafers from different positions of a B-doped Czochralski silicon (Cz-Si) ingot. Then, the cells were subjected to a dark annealing (200 °C, 30 min), the first LID (45 °C, 1 sun, 12 h), an electrical injection regeneration (175 °C, 18 A, 30 min) and the second LID (45 °C, 1 sun, 12 h) in order, and the variations of performance of the cells with processing time were measured. It was found that after the electrical injection regeneration, the efficiency losses of PERC cells decreased from 1.28−1.76solute in the first LID to 0.09−0.16solute in the second LID, while those of Al-BSF cells decreased from 0.3−0.66solute in the first LID to 0 in the second LID. The efficiency losses of PERC cells during the first LID were caused by the co-action of B-O-defect-induced LID (BO-LID)... [more]
Induction Motor Supplied with Voltage Containing Symmetrical Subharmonics and Interharmonics
Piotr Gnaciński, Damian Hallmann, Adam Muc, Piotr Klimczak, Marcin Pepliński
April 27, 2023 (v1)
Keywords: AC motors, harmonic distortion, induction motors, vibrations, voltage fluctuations
Sinusoidal voltage fluctuations can be considered a specific result of the occurrence of voltage subharmonics and interharmonics, which are components of low frequency or not being an integer multiple of the frequency of the fundamental voltage harmonic. These components—symmetrical subharmonics and interharmonics—are of the same magnitude, while their frequencies are symmetrical with respect to the fundamental frequency. Depending on their phase angles, various kinds of voltage fluctuations can be distinguished: amplitude modulation, phase modulation and intermediate modulation. In this study, the effect of phase angles on noxious phenomena in induction motors was analyzed. Additionally, torque pulsations and vibrations of an induction motor under sinusoidal voltage fluctuation and a single voltage subharmonic or interharmonic were compared. The investigations were performed with the finite element method and an experimental method. Among other findings, it was found that for some pha... [more]
Double Cathode Modification Improves Charge Transport and Stability of Organic Solar Cells
Tao Lin, Tingting Dai
April 27, 2023 (v1)
Keywords: charge transport, double cathode modification layer, organic solar cells
Introducing a cathode modification layer is an effective method to obtaining highly efficient organic solar cells (OSCs) and improving their stability. Herein, we innovatively introduced a double cathode modification layer (SnO2/ZnO) into a non-fullerene OSCs based on PM7:IT-4F and explored the mechanisms. The effects of SnO2/ZnO film on charge carriers transfer in OSCs are studied via a variety of electrical testing methods including Photo-CELIV measurements. As a result, a cathode buffer layer with low recombination rate and high carrier mobility could be introduced, which is beneficial to electron transport and collection. The champion device based on the double cathode modification layer acquires an efficiency of 12.91%, obviously higher than that of the single cathode modification layer (SnO2 or ZnO) device. Moreover, The SnO2/ZnO double layer is demonstrated to be of great help in the improvement of device stability, and our work could provide a new inspiration for the preparatio... [more]
Management Accounting System in the Management of an Intelligent Energy Sector Enterprise
Iwona Posadzińska, Małgorzata Grzeszczak
April 27, 2023 (v1)
Keywords: energy sector, intelligent management, managerial accounting
The aim of the article was to assess the implementation of the management accounting tools in managing an intelligent energy sector enterprise. The energy industry, characterized by high price fluctuation, rising costs, and the development of modern technologies, will in the future look for diversified sources of income and changes in business models. Energy entities will move towards intelligent management using management accounting tools, providing access to complete and up-to-date information from internal and external sources and extended management capabilities. In order to obtain answers to the questions, we conducted standardized interviews and an in-depth interview (IDI—individual in-depth interview) with large enterprises, with particular emphasis on the case of Hager Polo Ltd.
Composite Hydration Process of Clay Minerals Simulating Mineral Clay Components and Influence Mechanism of Cations
Huang Siyao, Xu Mingbiao, Xu Peng, Zhang Yu, Wang Xinying
April 27, 2023 (v1)
Subject: Other
Keywords: bentonite, clay minerals, hydration, mud shale hydration
Clay minerals are an important part of the mud shale reservoir, and their type of content has a great impact on the hydration of the formation. The hydration of clay minerals causes a decrease in drilling fluid performance, an increase in pore pressure, and a decrease in rock strength, leading to wellbore wall collapse. Therefore, it is important to study the influence of clay mineral hydration on well-wall stability. In this paper, we analyze the hydration process of clay minerals qualitatively and quantitatively by simulating the mineral clay fraction and the effect of the change in cations on their hydration and clarify the difference in the hydration of different clay minerals. The results show the following: (1) montmorillonite has the most obvious hydration and swelling effect, while the hydration of illite is mainly based on hydration and dispersion, which easily produce exfoliations and fall off in the stratum; kaolinite has poor hydration performance, while chlorite shows cert... [more]
Electricity Demand Elasticity, Mobility, and COVID-19 Contagion Nexus in the Italian Day-Ahead Electricity Market
Carlo Andrea Bollino, Maria Chiara D’Errico
April 27, 2023 (v1)
Keywords: COVID pandemia, electricity demand, energy–mobility–COVID nexus, lockdown effect
The magnitude of the impact of the pandemic on key variables, such as electricity demand, mobility of people and number of COVID-19 hospitalization cases, has been unprecedented. Existing economic models have not estimated the impact of sucokh events. This paper fills this gap, investigating the nexus among electricity demand elasticity, shifting behaviors of mobility and COVID-19 contagion with econometric estimation techniques. Firstly, using the single bids to purchase recorded in the Italian day-ahead wholesale electricity market in 2020, we estimate hourly electricity demand and price elasticity directly from short-run consumer behavior. Then, we analyze the effects of the main aspects of the pandemic, the health situation and the mobility contraction at the national level, on the estimated price elasticities. The period of heavy lockdown between 10 March and 3 June recorded a reduction in the price elasticity of electricity demand. However, when the pandemic broke out again at th... [more]
Effect of Slot Opening on Permanent Magnet Power Loss of a Permanent Magnet Synchronous Machine Driven by PWM
Guohui Yang, Xiaolu Wang, Chaofan Yang, Danyang Wang, Hao Wu, Xin Wang
April 27, 2023 (v1)
Keywords: finite element method (FEM), inverter driving, permanent magnet loss, permanent magnetic synchronous machine (PMSM)
In this study, the influence of slot opening on the leakage reactance, power factors, winding current, and air gap flux density, as well as other parameters of the surface-mounted permanent magnet synchronous motor driven by an inverter is analyzed using the two-dimensional time-step finite element method. Thus, the law of permanent magnet power loss caused by slot opening under PWM qa obtained. The results show that the leakage reactance of the motor increased when the slot opening decreased from 7 mm to 2 mm. Then, the armature ripple current caused by the inverter was found to be suppressed well, and the high harmonic current was filtered well. This reduced the amplitude of the high-order harmonic of the air gap flux density, and the permanent magnet power loss was reduced by nearly 75%. Finally, two prototypes with different slot openings were tested for permanent magnet temperature rise, which verified the analysis method and calculation results proven in this paper.
The Review and Development of Devices with an Increasing Rate of Penetration (ROP) in Deep Formation Drilling Based on Drill String Vibration
Yongwang Liu, Yixiang Niu, Zhichuan Guan, Shuquan Lyu
April 27, 2023 (v1)
Subject: Other
Keywords: bottom-hole pressurization, drill string vibration reduction, energy of drill string vibration, high-pressure pulsed jet, ROP increase
The oil and gas resources stored in deep strata are an important replacement field of the petroleum industry. Accelerating the exploration and development of deep oil and gas is of great significance to the security of energy strategy. Drilling is the primary link and necessary means of deep oil and gas exploration and development. Slow drilling speed is one of the key problems restricting the exploration and development of deep oil and gas. The research and development of down-hole equipment with an increasing ROP provides a technical means for increasing the ROP. However, the energy of existing down-hole equipment with an increasing ROP comes from the drilling circulation medium, and the ROP increase effect of such equipment is relatively obvious in shallow and middle formations. However, with the increase in well depth, energy in the circulation medium increasingly struggles to reach deeper formations, and the ROP increase effect is not good at the later stage of drilling. In the dr... [more]
Solar Thermochemical CO2 Splitting Integrated with Supercritical CO2 Cycle for Efficient Fuel and Power Generation
Xiangjun Yu, Wenlei Lian, Ke Gao, Zhixing Jiang, Cheng Tian, Nan Sun, Hangbin Zheng, Xinrui Wang, Chao Song, Xianglei Liu
April 27, 2023 (v1)
Keywords: cerium dioxide, concentrated solar, solar fuel, thermochemical cycle, thermodynamic analysis
Converting CO2 into fuels via solar-driven thermochemical cycles of metal oxides is promising to address global climate change and energy crisis challenges simultaneously. However, it suffers from low energy conversion efficiency (ηen) due to high sensible heat losses when swinging between reduction and oxidation cycles, and a single product of fuels can hardly meet multiple kinds of energy demands. Here, we propose an alternative way to upsurge energy conversion efficiency by integrating solar thermochemical CO2 splitting with a supercritical CO2 thermodynamic cycle. When gas phase heat recovery (εgg) is equal to 0.9, the highest energy conversion efficiency of 20.4% is obtained at the optimal cycle high pressure of 260 bar. In stark contrast, the highest energy conversion efficiency is only 9.8% for conventional solar thermochemical CO2 splitting without including a supercritical CO2 cycle. The superior performance is attributed to efficient harvesting of waste heat and synergy of CO... [more]
Advanced Energy Efficiency Systems in Buildings
David Borge-Diez
April 27, 2023 (v1)
Energy efficiency is becoming one of the key research topics in the energy field and has, therefore, attracted extensive attention in recent research [...]
Experimental Study on the Behavior of Aluminum Fuse Element Inside 24 kV, 50 kA High-Voltage Fuses
Cristian-Eugeniu Sălceanu, Marcel Nicola, Claudiu-Ionel Nicola, Daniel Ocoleanu, Cătălin Dobrea, Daniela Iovan, Sorin Enache
April 27, 2023 (v1)
Keywords: aluminum, heating, high power, high–voltage fuses, maximum breaking current, time–current
High-voltage fuses are found in most electrical installations, where they are used for overcurrent protection and are the pieces of equipment providing the highest degree of protection for the lowest initial cost. This article focuses on the behavior of high-voltage fuses containing a fuse element entirely made of aluminum. We made high-power linear electrical circuits for experiments on these fuses under the most severe operating conditions. The article presents the construction details of the fuse element and its features, as well as various arc extinguishing media. The heating behavior and time−current characteristics were studied in comparison with fuses made of copper. We obtained the maximum instantaneous value of the current reached during interruption for a 24 kV, 50 kA, 50 A fuse, as well as the value of the minimum breaking current.
Seismic Response Sensitivity Analysis of the Raft Foundation NPP Reactor Building under Different Site Conditions
Liang Li, Rong Pan, Yu Lu
April 27, 2023 (v1)
Keywords: automatic seismic trip systems, ground motion parameters, nuclear power plant, soil–structure interaction
The seismic sensors used for automatic seismic trip systems (ASTS) of nuclear power plants (NPPs) are mainly arranged on the raft foundation of reactor buildings; however, the arrangement principle of seismic sensors is not clear. In order to analyze the seismic response sensitivity of the raft foundation of reactor building in NPPs, this paper carried out the seismic response sensitivity research at seven positions on the raft foundation of a reactor building under three site conditions, with two sets of time histories as input. The results show that (1) the peak acceleration of the outer ring point of the raft foundation was the largest, and the peak acceleration of the center point was the smallest; (2) the peak value of the floor response spectrum at the outer ring point of the raft foundation was the largest, and the peak value at the center point was the smallest. In an earthquake, the outer ring point of the raft foundation of the reactor building was the most sensitive. It was... [more]
An Approach for Determining Voltage Imbalance Contributions Based on Complex Independent Component Analysis
Márcio Arvelos Moraes, Vinícius Henrique Farias Brito, José Carlos de Oliveira
April 27, 2023 (v1)
Keywords: assigning imbalance contributions, complex independent component analysis, power quality, superposition method, voltage imbalance
In the context of power quality problems, the voltage imbalance index is relevant, given its harmful impacts on the networks and loads. Thus, reliable and viable methodologies for practical use are necessary to determine agents’ contributions. This article presents a noninvasive method for sharing responsibility for imbalances based on the principle of superposing the individual voltage imbalance produced by the parties. A procedure based on the Complex Independent Component Analysis (CICA) technique is proposed to meet the parameters required by the superposition method. Based on the measurements of voltages and currents carried out on the point of common coupling (PCC), the negative sequence impedances are determined using the CICA method under the terms needed by the superposition principle. The methodology’s effectiveness is evaluated through performance comparisons carried out over the process, in light of the response from the methods for sharing responsibilities currently publis... [more]
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