mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Energy Management and Optimization of Vehicle-to-grid Systems for Wind Power Integration

An approach to smoothing the fluctuations of largescale wind power is investigated using vehicle-to-grid (V2G) systems. First, an energy management and optimization system is designed and modeled. By using the wavelet packet decomposition method, the target grid-connected wind power, the required electric vehicle (EV) power, and supercapacitor power are determined. The energy management model for EVs is then developed by introducing a knapsack problem that can evaluate the needs of an EV fleet. Furthermore, an optimized dispatch strategy for EVs and wind power is developed by using a dynamic programming method. A case study demonstrates that the energy management and optimization method for V2G systems achieves noticeable performance improvements over benchmark techniques.
Modeling Arbitrage of an Energy Storage Unit Without Binary Variables

Energy storage device cannot be operated in charging and discharging modes simultaneously. Existing model utilizes binary variables to enforce such a request of complementarity. This paper discusses the implementation of a non-complementary strategy and reveals that strict complementarity can be replaced with a weaker yet linear constraint without jeopardizing practical viability. Hence, the arbitrage of an energy storage unit can be modeled via a linear program. The proposed model provides additional dimension of flexibility which can improve the profit of electricity arbitrage. The linearity benefits theoretical analysis on more sophisticated optimization problems that entails using duality and convex analysis.
Status and Progress on an HTS Strand with Quasi-isotropic Critical Current

The coated conductors (CCs), also known as the second-generation high-temperature superconducting (2G HTS) tape, has attractive potential applications in transmissions at low magnetic field/liquid nitrogen temperatures and high-field applications at low temperatures due to their excellent critical current density and mechanical performance. Its critical current density has strong anisotropy, particularly at 77 K. Because the single tape has limited capacity of carrying current, the cable or strand making of multi-tapes, stacked in parallel, is necessary. Within recent years, several cables, such as the Roebel cable,CORC cable, TSTC cable,TS cable, and the HTS-CroCo cable,were proposed. This paper presents a status and progress on a type of HTS strand made from REBCO tapes. Its quasi-isotropic critical current is experimentally confirmed for liquid nitrogen temperature, mechanical characteristics, AC losses, thermal stability, and quench characterizations are also researched. Finally, the feasible process for the production of practical length of such strand is described by processing 10 m long sample, which is promising for applications of high fields or power transmission.
Optimal Auxiliary Frequency Control of Wind Turbine Generators and Coordination with Synchronous Generators

Auxiliary frequency control of a wind turbine generator (WTG) has been widely used to enhance the frequency security of power systems with high penetration of renewable energy. Previous studies recommend two types of control schemes, including frequency droop control and emulated inertia control, which simulate the response characteristics of the synchronous generator (SG). This paper plans to further explore the optimal auxiliary frequency control of the wind turbine based on previous research. First, it is determined that the virtual inertia control has little effect on the maximum rate of change of frequency (Max-ROCOF) if the time delay of the control link of WTG is taken into consideration. Secondly, if a WTG operates in maximum power point tracking (MPPT) mode and uses the rotor deceleration for frequency modulation, its optimal auxiliary frequency control will contain only droop control. Furthermore, if the droop control is properly delayed, better system frequency response (SFR) will be obtained. The reason is that coordination between the WTG and SG is important for SFR when the frequency modulation capability of the WTG is limited. The frequency modulation capability of the WTG is required to be released more properly. Therefore, when designing optimal auxiliary frequency control for the WTG, a better control scheme is worth further study.
Positive- and Zero-Sequence Impedance Estimation of YNynO+d-Connected Main Power Transformers in Wind Power Applications

With the increased penetration of non-conventional renewable energy resources, such as wind power plants (WPPs), into the power system, a lot of interest has been placed on studying their impact for system protection, planning and operations to ensure continued reliability of the electric grid. The impact of WPPs on the grid is typically identified during generation interconnection studies. One of the challenges faced by protection and planning engineers, at an early stage in this process, is that many of the studies involving these power plants must be performed without specific data available because the equipment is not built yet. Among all the needed data, a particular interest in this study is placed on the positive- and zero-sequence impedances of the main power transformer (MPT) that interconnects a wind power plant to the transmission system due to its contribution to short-circuit current during ground faults. The most commonly found in practice MPT winding configurations is a high-voltage winding in wye with neutral bushing; a low-voltage winding in wye with neutral bushing without phase shift between these windings, and a stabilizing tertiary winding connected in delta that is not designed for external loading designated as YNynO+d. Thus, this paper proposes a methodology to estimate the sequence impedances of YNynO+d transformers from a statistical point of view applying clustering and regression analyses on existing MPT test report data.
Active Cell Balancing Control Strategy for Parallelly Connected LiFePO_4 Batteries

While several recent studies have focused on eliminating the imbalance of energy stored in series-connected battery cells, very little attention has been given to balancing the energy stored in parallel-connected battery cells. As such, this paper aims at presenting a new balancing approach for parallel LiFePO_4 battery cells. In this regard, a Backpropagation Neural Network (BPNN) based technique is employed to develop a Battery Management System (BMS) that can assess the charging status of all cells and control its operations through a DC/DC Buck-Boost converter. Simulation results demonstrate the effectiveness of the proposed approach in balancing the energy stored in parallel-connected battery cells in which the state of charge (SoC) estimation error is found to be only 1.15%.
Stability Analysis of Multi-paralleled Grid-connected Inverters Including Distribution Parameter Characteristics of Transmission Lines

The sparse distribution characteristics of renewable energy resources can lead to there being tens of kilometers of transmission lines between a grid-connected inverter and the actual grid. Accurate analysis of the stability of such gridconnected inverter systems currently involves using a complex hyperbolic function to shaped model of the transmission line circuit. This has proved to be problematic, so, drawing upon the distribution parameter characteristics of transmission lines, this paper looks at how to use impedance-based stability criteria to assess the stability of multi-paralleled grid-connected inverters. First, the topology of multi-paralleled inverters connected to the grid via transmission lines is established, using each transmission line terminal as a grid connection point. Each grid-connected system is taken to be equivalent to a small-signal circuit model of the "current source-grid". Euler's formula and the Nyquist stability criterion are combined to assess the stability of the associated grid-connected current transfer functions and evaluate the stability of the grid-connected current. Finally, a simulation analysis circuit is constructed to verify whether power line intervention will cause stability problems in the grid-connected system. Overall, it is found that long-distance transmission lines are more likely to cause unstable output of the grid-connected current. It is also found that the number of grid-connected inverters, the short-circuit ratio (SCR), the distorted grid and the inverter parameters can all have a significant impact on the stability of the grid-connected current.
Coordinated Damping Optimization Control of Sub-synchronous Oscillation for DFIG and SVG

Currently, the power electronics-based devices, including large-scale non-synchronized generators and reactive power compensators, are widely used in power grids. This helps introduce the coupling interactions between the devices and the power grid, resulting in a new sub-synchronous oscillation phenomenon. It is a critical element for the stability operation of the power grid and its devices. In this paper, the sub-synchronous oscillation phenomenon of the power grid connected with largescale wind power generation is analyzed in detail. Then, in order to damp the sub-synchronous oscillation, a coordinated damping optimization control strategy for wind power generators and their reactive power compensators is proposed. The proposed coordinated control strategy tracks the sub-synchronous oscillation current signal to correct the corresponding control signal, which increases the damping of power electronics. The response characteristics of the proposed control strategy are analyzed, and a self-optimization parameter tuning method based on sensitivity analysis is proposed. The simulation results validate the effectiveness and the availability of the proposed control strategy.
Renewable Scenario Generation Using Controllable Generative Adversarial Networks with Transparent Latent Space

With the growing penetration of renewable energy sources in power systems, it becomes increasingly important to characterize their inherent variability and uncertainty. Scenario generation is a key approach to provide a series of possible power scenarios in the future for the system planner and operator to make decisions. In this paper, a data-driven method is presented for renewable scenario generation using stable and controllable generative adversarial networks with transparent latent space (ctrl-GANs). The machine learning based algorithm can capture the nonlinear and dynamic renewable patterns without the need for modeling assumptions and complicated sampling techniques. The orthogonal regularization and spectral normalization are adopted to improve the training stabilization of the GAN model. To control the generation process, a relationship is built between features of the generated scenarios and latent vectors on the manifold. Moreover, several new metrics for GANs are used to evaluate the quality of the scenarios. The proposed approach is applied to generate realistic time series data of wind and photovoltaic power. The results demonstrate that our method has a better performance on numerical stabilization and is able to control the generation process with latent space.
Interactive Visual Analysis on the Attack and Defense Drill of Grid Cyber-physical Systems

The open and distributed connection of the power system makes it vulnerable to various potential cyber-attacks, which may lead to power outages and even casualties. Therefore, the construction of attack and defense drill (ADD) platforms for attack mechanism investigation and protection strategy evaluation has become a research hotspot. However, for the massive and heterogeneous security analysis data generated during the drill, it is rare to have a comprehensive and intuitive method to visually and efficiently display the perspective of the attacker and defender. In order to solve this problem, this paper proposes a visual analysis scheme of an ADD framework for a grid cyberphysical system (GCPS) based on the interactive visual analysis method. Specifically, it realizes system weakness discovery based on knowledge visualization, optimization of the detection model and visualization interaction. Finally, the case study on the simulation platform of ADD proves the effectiveness of the proposed method.
The effect of iron on the sound velocities of δ-AlOOH up to 135 GPa

δ-(Al,Fe)OOH is considered to be one of the most important hydrous phases on Earth, remaining stable under the extreme conditions throughout the mantle. The behavior of δ-(Al,Fe)OOH at high pressure is essential to understanding the deep water cycle. δ-(Al_(0.956)Fe_(0.044))OOH crystals synthesized at 21 GPa and 1473 K were investigated by high-pressure Brillouin light scattering spectroscopy and synchrotron X-ray diffraction up to 135.4 GPa in diamond anvil cells. The incorporation of 5 mol% FeOOH increases the unit-cell volume of δ-AlOOH by ~1% and decreases the shear-wave velocity(VS)by ~5% at 20-135 GPa. In particular, the compressional(V_P)and shear(V_S)wave velocities of δ-(Al_(0.956)Fe_(0.044))OOH are 7%-16% and 10%-24% greater than all the major minerals in the mantle transition zone including wadsleyite, ringwoodite, and majorite. The distinctly high sound velocities of δ-(Al_(0.956)Fe_(0.044))OOH at 20-25 GPa may contribute to the seismic anomalies observed at ~560-680 km depths in the cold and stagnant slab beneath Izu-Bonin and/or Korea. Furthermore, the VS of δ-(Al_(0.956)Fe_(0.044))OOH is about 10% and 4%-12% lower than iron-bearing bridgmanite Mg_(0.96)Fe_(0.05)Si_(0.99)O_3 and ferropericlase(Mg_(0.92)Fe_(0.08))O, respectively, under the lowermost mantle conditions, which might partially contribute to the large low-shear-velocity provinces and ultralow velocity zones at the bottom of the lower mantle.
Depositional age and tectonic environment of the Gouap banded iron formations from the Nyong group, SW Cameroon: Insights from isotopic,geochemical and geochronological studies of drillcore samples

The discovery of the Gouap banded iron formations(BIFs)-hosted iron mineralization in the northwestern of the Nyong Group(Ntem Complex)in southwestern Cameroon provides unique insights into the geology of this region. In this contribution, we firstly report detailed study of geochemistry, isotopic and geochronology of well preserved samples of the Gouap BIFs collected from diamond drillcores. The Gouap BIFs consist mainly of amphibole BIFs and amphibole-pyrite BIFs characterized by dominant Fe_2O_3 + SiO_2 contents and variable contents of CaO,MgO and SO_3, consistent with the presence of amphibole, chlorite, epidote and pyrite, formed during amphibolite facies metamorphism and overprinted hydrothermal event. The amphibole-pyrite BIFs are typically enriched in trace and rare earth elements(REE)compared to the amphibole BIFs, suggesting the influence of detrital materials as well as secondary hydrothermal alteration. The Post Archean Australian Shale(PAAS)-normalized REE-Y profiles of the Gouap BIFs display positive La, Eu anomalies, weak negative Ce anomalies, indicating a mixture of low-temperature hydrothermal fluids and relatively oxic conditions probably under relative shallow seawater. We present here the first isotopic data of BIFs within the Ntem Complex. The δ~(30)Si_(NBS28) values of the quartz from the Gouap BIFs vary from -1.5‰ to -0.3‰ and from -0.8‰ to -0.9‰ for the amphibole BIFs and amphibole-pyrite BIFs, respectively. The quartz has δ~(18)OV-SMOW values of 6.8‰-9.5‰(amphibole BIFs)and 9.2‰-10.6‰(amphibole-pyrite BIFs). The magnetite from the Gouap BIFs shows δ~(18)O values ranging from -3.5‰ to -1.8‰ and from -3‰ to -1.7‰ for the amphibole BIFs and amphibole-pyrite BIFs, respectively. Moreover, the pyrite grains in the amphibole-pyrite BIFs display δ~(34)S values of 1.1‰-1.8‰. All isotopic data of the Gouap BIFs confirm that they might have precipitated from low-temperature hydrothermal fluids with detrital input distant from the volcanic activity. According to their geochemical and isotopic characteristics, we propose that the Gouap BIFs belong to the Superior type. In situ U-Pb zircon dating of BIFs was conducted to assess the BIF depositional age based on strong evidence of zircon in thin section. The Gouap BIFs were probably deposited at 2422 ± 50 Ma in a region where sediments extended from continental shelf to deep-water environments along craton margins like the Cau^e Formation of the Minas Supergroup, Brazil. The studied BIFs have experienced regional hydrothermal activity and metamorphism at 2089 ± 8.3 Ma during the Eburnean-Transamazonian orogeny. These findings suggest a physical continuity between the protocratonic masses of both Sao Francisco and Congo continents in the Rhyacian Period.
Microstructure and mechanical characteristics of AA6061-T6 joints produced by friction stir welding,friction stir vibration welding and tungsten inert gas welding:A comparative study

This study compared the microstructure and mechanical characteristics of AA6061-T6 joints produced using friction stir welding (FSW),friction stir vibration welding (FSVW),and tungsten inert gas welding (TIG).FSVW is a modified version of FSW wherein the joining specimens are vibrated normal to the welding line during FSW.The results indicated that the weld region grains for FSVW and FSW were equiaxed and were smaller than the grains for TIG.In addition,the weld region grains for FSVW were finer compared with those for FSW.Results also showed that the strength,hardness,and toughness values of the joints produced by FSVW were higher than those of the other joints produced by FSW and TIG.The vibration during FSW enhanced dynamic recrystallization,which led to the development of finer grains.The weld efficiency of FSVW was approximately 81%,whereas those of FSW and TIG were approximately 74% and 67%,respectively.
Tin recovery from a low-grade tin middling with high Si content and low Fe content by reduction–sulfurization roasting with anthracite coal

A new method for separating and recovering tin from a low-grade tin middling with high Si content and low Fe content by roasting with anthracite coal was researched by studying the reaction mechanism and performing an industrial test,in which the Sn was sulfurized into SnS(g) and then collected using a dust collector.The Fe–Sn alloy may be formed at roasting temperatures above 950°C,and like the roasting temperature increases,the Sn content and Sn activity in this Fe–Sn alloy decrease.Also,more FeS can be formed at higher temperatures and then the formation of FeO–FeS with a low melting point is promoted,which results in more serious sintering of this low-grade tin middling.And from the thermodynamics and kinetics points of view,the volatilization of the Sn decreases at extremely high roasting temperatures.The results of the industrial test carried out in a coal-fired rotary kiln show that the Sn volatilization rate reaches 89.7% and the Sn is concentrated in the collected dust at a high level,indicating that the Sn can be effectively extracted and recovered from the low-grade tin middling with a high Si content and low Fe content through a reduction–sulfurization roasting process.
Cell morphology,porosity,microstructure and mechanical properties of porous Fe–C–P alloys

Open cell steel foams were successfully fabricated through the powder metallurgy route using urea granules as the water leachable space holder in the present study.The influence of different amounts of phosphorus (0,0.5wt%,1wt%,2wt%,and 4wt%) was investigated on the cell morphology,porosity,microstructure of cell walls,and mechanical properties of steel foams.The cell morphology and microstructure of the cell walls were evaluated using an optical microscope equipped with image processing software and a scanning electron microscope equipped with an energy dispersive X-ray spectrometer.In addition,the compression tests were conducted on the steel foams using a universal testing machine.Based on microscopic images,the porous structure consists of spherical cells and irregularly shaped pores that are distributed in the cell walls.The results indicated that by increasing the phosphorus content,the porosity increases from 71.9% to 83.2%.The partially distributed ferrite and fine pearlite was observed in the microstructure of the cell walls,and α-Fe and Fe3P eutectic extended between the boundaries of agglomerated iron particles.Furthermore,elastic and long saw-toothed plateau regions were observed before fracture in the compressional stress –strain curves.According to the results,by increasing the phosphorus content from 0 to 4wt%,the plateau region of the stress–strain curves shifts to the right and upward.Therefore,increasing phosphorus content causes improvement in the mechanical properties of steel foams.
Effect of pH on the photocatalytic removal of silver ions by β-MnO_2 particles

The presence of silver ions (Ag(I)) in wastewater has a detrimental effect on living organisms.Removal of soluble silver,especially at low concentrations,is challenging.This paper presents the use of β-MnO_2 particles as a photocatalyst to remove Ag(I) ions selectively from aqueous solution at various pH levels.Inductively coupled plasma mass spectrometry (ICP-MS),X-ray diffraction (XRD),field emission electron microscope (FESEM),transmission electron microscopy (TEM),and X-ray photoelectron microscopy (XPS) were employed to determine the removal efficiency and to characterize the deposition of silver onto the surface of β-MnO_2 particles.The optimum pH for the removal of Ag(I) ions was at pH 4 with 99% removal efficiency under 1 h of visible light irradiation.This phenomenon can be attributed to the electrostatic attraction between β-MnO_2 particles and Ag(I) ions as well as the suppression of electron–hole recombination in the presence of H~+ions.
Development of calcium coke for CaC_2 production using calcium carbide slag and coking coal

A type of calcium coke was developed for use in the oxy-thermal process of calcium carbide production. The calcium coke was prepared by the co-pyrolysis of coking coal and calcium carbide slag, which is a solid waste generated from the chlor-alkali industry. The characteristics of the calcium cokes under different conditions were analyzed experimentally and theoretically. The results show that the thermal strength of calcium coke increased with the increase in the coking coal proportion, and the waterproof property of calcium coke also increased with increased carbonation time. The calcium coke can increase the contact area of calcium and carbon in the calcium carbide production process. Furthermore, the pore structure of the calcium coke can enhance the diffusion of gas inside the furnace, thus improving the efficiency of the oxy-thermal technology.
Highly transparent ceramics for the spectral range from 1.0 to 60.0 μm based on solid solutions of the system AgBr-AgI-TlI-TlBr

The article is devoted to the technology for obtaining optical ceramics of AgBr-TlI and AgBr-TlBr0.46I0.54 systems and manufacturing samples with different compositions. The new heterophase crystal ceramics are transparent without absorption windows in the spectral range from 1.0 to 60.0 μm. In the ceramics' transparency spectra based on the AgBr-TlI and AgBr-TlBr0.46I0.54 systems fusibility diagrams, with an increase in the thallium halides mass fraction, as well as the replacement of the bromine ion with iodine, the maximum transparency shifts to a long infrared region.