Hasil untuk "Production of electric energy or power. Powerplants. Central stations"

Min Wang, Chunliang Wang, Zimo Liu et al.

Kratika Yadav, Mukesh Singh

Jiawen Chen, Yuan Zou, Jun Zhang et al.

Nader Younis, Tarek Younis, Mahmoud A. Gaafar et al.

Ahmed Eleslambouly, Tarek Khalifa, Omar Aldhanhani et al.

The Penobscot Field, located within the Scotian Basin offshore Nova Scotia, Canada, represents an underexplored hydrocarbon field with potential for future development. Previous studies have been confined to specific reservoir intervals without integrating multiple stratigraphic levels, and a comprehensive static reservoir characterization and volumetric assessment of the Penobscot Field has yet to be undertaken, constraining its full development evaluation. This study presents a comprehensive characterization of the field by integrating geological, geophysical, and petrophysical datasets, leading to static hydrocarbon reserve estimation. The workflow involves seismic interpretation, structural modeling, petrophysical evaluation, and static volumetric calculations. Seismic analysis revealed a structurally complex setting dominated by normal and inverted faults, with reservoir intervals primarily within the Missisauga Formation, which is subdivided into upper, middle, and lower units. Petrophysical evaluation from well logs and core data identified key reservoir properties, including porosity ranging from 12 % to 28 %, permeability spanning from 1 to 1000 mD, and variable water saturations. Stochastic modeling of facies and petrophysical attributes provided insights into lateral and vertical heterogeneity. The Penobscot Field's original oil-in-place ranges from 41.6 × 106 m3 to 109.7 × 106 m3, with the Middle Missisauga sands presenting the highest reservoir potential. Fault seal analysis indicated predominantly sealing behavior in the shallow sections and semi-permeable conditions at greater depths, suggesting potential lateral migration pathways. The results underscore the field's hydrocarbon potential while emphasizing the significance of structural complexity, facies distribution, and petrophysical variability in reservoir quality, as well as its potential for future development or utilization of similar sand reservoirs for CO2 storage utilization. This work provides the first fully integrated static reservoir model of the Penobscot Field, offering critical insights for delineating the hydrocarbon reservoirs potential and future production strategies in the Scotian Basin.

Shevchenko S., Danylchenko D., Hanus R. et al.

The article discusses methods for calculating the moisture discharge voltage of insulators under various operating conditions (pollution, humidity, etc.) to identify patterns of environmental influence on operational characteristics, as well as to improve the reliability and safety of power grids. The main aim of the study is to compare two approaches to calculating the moisture discharge characteristics of insulators: the classical method based on the Tepler formula and an alternative approach that utilizes generalized parameters. These parameters can be easily obtained from the technical characteristics of insulators or design standards for automated calculations. To achieve this goal, the authors addressed several important tasks. First, a comprehensive analysis of the behavior of electrical discharges on the surface of insulators under various operating conditions, including standard and adverse environments, was conducted. Second, an automated tool was developed to quickly and accurately determine the values of moisture discharge voltage. Third, the proposed method was experimentally validated using the LK 70-110 insulator. The tests revealed a discharge voltage of 549 kV and an electric field intensity of 2.1 kV/cm, confirming the accuracy of the calculation method. The key findings of the study highlight the importance of considering factors such as the properties of insulator surfaces and the degree of contamination, especially in underground substations where humidity and pollution exhibit specific characteristics. The proposed approach proved effective both in standard and challenging operating conditions. The significance of the results lies in the creation of a tool that simplifies the calculation of moisture discharge characteristics of insulators.

Mihitha Maithripala, Zongli Lin

The increasing deployment of distributed Battery Energy Storage Systems (BESSs) in modern power grids necessitates effective coordination strategies to ensure state-of-charge (SoC) balancing and accurate power delivery. While distributed control frameworks offer scalability and resilience, they also raise significant privacy concerns due to the need for inter-agent information exchange. This paper presents a novel privacy-preserving distributed control algorithm for SoC balancing in a networked BESS. The proposed framework includes distributed power allocation law that is designed based on two privacy-preserving distributed estimators, one for the average unit state and the other for the average desired power. The average unit state estimator is designed via the state decomposition method without disclosing sensitive internal states. The proposed power allocation law based on these estimators ensures asymptotic SoC balancing and global power delivery while safeguarding agent privacy from external eavesdroppers. The effectiveness and privacy-preserving properties of the proposed control strategy are demonstrated through simulation results.

Yun Shi, Qingshan Xu, Aoxue Cheng

Zhaoqiang Yang, Longtan Li, Rui Yao et al.

Yuanshi Zhang, Wenyan Qian, Jun Shao et al.

Active power sharing and voltage regulation are two of the major control challenges in the operation of the voltage source converter based multi-terminal high-voltage DC (VSC-MTDC) system when integrating large-scale offshore wind farms (OWFs). This paper proposes two novel adaptive voltage reference based droop control methods to regulate pilot DC voltage and share the power burden autonomously. The proposed Method I utilizes DC grid lossy model with the local voltage droop control strategy, while the proposed Method II adopts a modified pilot voltage droop control (MPVDC) to avoid the large errors caused by the DC grid lossless model. Dynamic simulations of a five-terminal MTDC grid are carried out using MATLAB/Simulink SimPowerSystems /Specialized Technology to verify the proposed autonomous control methods under various types of disturbance and contingency. In addition, comparative study is implemented to demonstrate the advantages of the proposed methods.

Junkun Zhang, Rong Han, Ertao Lei et al.

The rapid and large-scale renewable energy development poses new challenges for the traditional power grid, particularly with the increasing utilization of high-power electronic interfaces. To address this, a novel grid simulator topology and its control strategy are proposed, which can generate various required waveforms with high performance. The grid simulator adopts a modular multilevel structure, a three-phase PWM module, and an H-bridge module with a shared DC bus. Model predictive control (MPC) outputs high-quality, fast voltage waveforms for accurate voltage tracking. Additionally, the model reference adaptive control (MRAC) is integrated into the PWM converter in the pre-stage to estimate the network side inductance value, which is used to improve the system’s robustness. Moreover, a switching distribution method is proposed for feedforward control to enhance reliability. Through simulation and experiment, it is verified that the proposed power grid simulator and its control strategy can effectively and accurately generate various fault waveforms such as voltage drop, voltage abrupt change, and abrupt frequency change. As a result, it can be used as test equipment for renewable energy or power electronic equipment.

Shoya Ohsumi, Yoshiki J. Sato, Ryuji Okazaki

Materials with axis-dependent conduction polarity are known as p×n-type or goniopolar conductors that can be used for transverse thermoelectric devices, allowing the longitudinal thermal current to be converted into the transverse electrical current. Here, we have performed experimental and computational studies on the transport properties of WSi_{2} single crystals, in which such axis-dependent conduction polarity of the thermopower and the Hall coefficient have recently been reported, and demonstrated the transverse thermoelectric effect by applying the temperature gradient in a direction rotated 45^{∘} from the crystallographic axis. We have observed strongly sample-dependent transport properties, which have also been observed in previous studies, and together with first-principles calculations we show that such sample-dependent transport properties originate from the band-dependent scattering rates of carriers. The calculated band-resolved Peltier conductivity shows that the mixed-dimensional electronic structure consisting of a quasi-one-dimensional electron Fermi surface and a quasi-two-dimensional hole surface is a key property for the axis-dependent conduction polarity. The directly obtained transverse thermoelectric figure of merit is comparable to that of the anomalous Nernst materials, implying that the present material is a potential candidate for transverse thermoelectric conversion.

Xiao Li, Jizheng Zhong, Songyang An et al.

Body weight support (BWS) systems are crucial in gait rehabilitation for individuals incapacitated due to injuries or medical conditions. Traditional BWS systems typically employ either static mass–rope or dynamic mass–spring–damper configurations, which can result in inadequate support stiffness, thereby leading to compromised gait training. Additionally, these systems often lack the flexibility for easy customization of stiffness, which is vital for personalized rehabilitation treatments. A novel BWS system with online variable stiffness is introduced in this study. This system incorporates a drive mechanism governed by admittance control that dynamically adjusts the stiffness by modulating the tension of a rope wrapped around a drum. An automated control algorithm is integrated to manage a smart anti-gravity dynamic suspension system, which ensures consistent and precise weight unloading adjustments throughout rehabilitation sessions. Walking experiments were performed to evaluate the displacement and load variations within the suspension ropes, thereby validating the variable-stiffness capability of the system. The findings suggest that the online variable-stiffness BWS system can reliably alter the stiffness levels and that it exhibits robust performance, significantly enhancing the effectiveness of gait rehabilitation. The newly developed BWS system represents a significant advancement in personalized gait rehabilitation, offering real-time stiffness adjustments and ongoing weight support customization. It ensures dependable control and robust operation, marking a significant step forward in tailored therapeutic interventions for gait rehabilitation.

Hannes Gernandt, Bernardo Severino, Xinyi Zhang et al.

Electric vehicles (EV) are an important part of future sustainable transportation. The increasing integration of EV charging stations (EVCSs) in the existing power grids require new scaleable control algorithms that maintain the stability and resilience of the grid. Here, we present such a control approach using an averaged port-Hamiltonian model. In this approach, the underlying switching behavior of the power converters is approximated by an averaged non-linear system. The averaged models are used to derive various types of stabilizing controllers, including the typically used PI controllers. The pH modeling is showcased by means of a generic setup of an EVCS, where the battery of the vehicle is connected to an AC grid via power lines, converters, and filters. Finally, the control design methods are compared for the averaged pH system and validated using a simulation model of the switched charging station.

Pikkin Lau, Lingfeng Wang, Wei Wei et al.

In this paper, a novel cyber-insurance model design is proposed based on system risk evaluation with smart technology applications. The cyber insurance policy for power systems is tailored via cyber risk modeling, reliability impact analysis, and insurance premium calculation. A stochastic Epidemic Network Model is developed to evaluate the cyber risk by propagating cyberattacks among graphical vulnerabilities. Smart technologies deployed in risk modeling include smart monitoring and job thread assignment. Smart monitoring boosts the substation availability against cyberattacks with preventive and corrective measures. The job thread assignment solution reduces the execution failures by distributing the control and monitoring tasks to multiple threads. Reliability assessment is deployed to estimate load losses convertible to monetary losses. These monetary losses would be shared through a mutual insurance plan. To ensure a fair distribution of indemnity, a new Shapley mutual insurance principle is devised. Effectiveness of the proposed Shapley mutual insurance design is validated via case studies. The Shapley premium is compared with existent premium designs. It is shown that the Shapley premium has high indemnity levels closer to those of Tail Conditional Expectation premium. Meanwhile, the Shapley premium is nearly as affordable as the coalitional premium and keeps a relatively low insolvency probability.

Hongyu Liu, Cheng Wang, Jiawei Zhu

Claudia C. Zuluaga-Gómez, Balram Tripathi, Christian O. Plaza-Rivera et al.

In this study, we are reporting the impact of the incorporation of ferroelectric nanoparticles (FNPs), such as BaTiO₃ (BTO), BiFeO₃ (BFO), Bi₄NdTi₃Fe_0.7Ni_0.3O₁₅ (BNTFN), and Bi₄NdTi₃Fe_0.5Co_0.5O₁₅ (BNTFC), as well as the mass loading of sulfur to fabricated solvent-free sulfur/holey graphene-carbon black/polyvinylidene fluoride (S/FNPs/CBhG/PVDF) composite electrodes to achieve high areal capacity for lithium-sulfur (Li-S) batteries. The dry-press method was adopted to fabricate composite cathodes. The hG, a conductive and lightweight scaffold derived from graphene, served as a matrix to host sulfur and FNPs for the fabrication of solvent-free composites. Raman spectra confirmed the dominant hG framework for all the composites, with strong D, G, and 2D bands. The surface morphology of the fabricated cathode system showed a homogeneous distribution of FNPs throughout the composites, confirmed by the EDAX spectra. The observed Li⁺ ion diffusion coefficient for the composite cathode started at 2.17 × 10⁻¹⁶ cm²/s (S₂₅(CBhG)₆₅PVDF₁₀) and reached up to the highest value (4.15 × 10⁻¹⁵ cm²/s) for S₂₅BNTFC₅(CBhG)₆₀PVDF₁₀. The best discharge capacity values for the S₂₅(CBhG)₆₅PVDF₁₀ and S₂₅BNTFC₅(CBhG)₆₀PVDF₁₀ composites started at 1123 mAh/g_s and 1509 mAh/g_s and dropped to 612 mAh/g_s and 572 mAh/g_s, respectively, after 100 cycles; similar behavior was exhibited by the other composites that were among the best. These are better values than those previously reported in the literature. The incorporation of ferroelectric nanoparticles in the cathodes of Li-S batteries reduced the rapid formation of polysulfides due to their internal electric fields. The areal capacity for the S₂₅(CBhG)₆₅PVDF₁₀ composites was 4.84 mAh/cm² with a mass loading of 4.31 mg_s/cm², while that for the S₂₅BNTFC₅(CBhG)₆₀PVDF₁₀ composites was 6.74 mAh/cm² with a mass loading of 4.46 mg_s/cm². It was confirmed that effective FNP incorporation within the S cathode improves the cycling response and stability of cathodes, enabling the high performance of Li-S batteries.

Minjie Lai, Dongying Zhang, Fenghua Chen et al.

Quinone organic materials are promising electrodes for the next lithium-ion batteries (LIBs) owing to their versatile molecular designs, high theoretical capacity, flexibility, sustainability, and environmental friendliness. However, quinone organic electrode materials can easily dissolve in organic electrolytes during the cycling process, which leads to the decay of capacity and poor cycling stability. Here, two metal-organic frames (MOFs), one-dimensional (1D) linear structural anthraquinone-2,3-dicarboxylate zinc coordination polymer (ZnAQDC) and two-dimensional (2D) structural anthraquinone-2,3-dicarboxylate manganese coordination polymer (MnAQDC), are synthesized by using anthraquinone 2,3-dicarboxylic acid, zinc acetate, and manganese acetate in a simple hydrothermal reaction. The formed 1D and 2D structures facilitate the insertion and extraction of lithium ions in and from carbonyl groups of anthraquinone. When MnAQDC is used as cathodes for LIBs, MnAQDC electrodes show an initial discharge capacity of ~63 mAh g⁻¹ at 50 mA g⁻¹. After 200 cycles, the MnAQDC electrode still maintains the specific capacity of ~45 mA h g⁻¹, which exhibits good cycle stability. the ZnAQDC electrode displays a initial discharge capacity of ~85 mA h g⁻¹ at 50 mA g⁻¹, and retains the specific capacity of ~40 mA h g⁻¹ after 200 cycles, showing moderate cyclic performance. The lithium-inserted mechanism shows that lithium ions are inserted and extracted in and from the carbonyl groups, and the valences of the Zn and Mn ions in the two MOFs do not change, and coordination metals do not contribute capacities for the two MOFs electrodes. The strategy of designing and synthesizing MOFs with 1D and 2D structures provides guidance for suppressing the dissolution and improving the electrochemical performance of quinone electrode materials.

Wei Yu, Yan Zheng, Yongqiang Zhang

With the enhancement of environmental awareness, China has put forward new carbon peak and carbon neutrality targets. Electric vehicles can effectively reduce carbon emissions in the use stage, and some retired power batteries can also be used in echelon, so as to replace the production and use of new batteries. How to calculate the reduction of carbon emission by the echelon utilization of retired power batteries in energy storage power stations is a problem worthy of attention. This research proposes a specific analysis process, to analyze how to select the appropriate battery type and capacity margin. Taking the BYD power battery as an example, in line with the different battery system structures of new batteries and retired batteries used in energy storage power stations, emissions at various stages in different life cycles were calculated; following this in carbon emission, reduction, by the echelon utilization of the retired power battery, was obtained. Finally, the overall carbon emissions that might be reduced by echelon utilization in the future were calculated according to the BYD’s battery loading volume and China’s total power battery loading volume in 2021. This research provides a quantitative analysis idea for the carbon emission reduction of power battery echelon utilization. Using this method could improve the process of echelon utilization, optimize the supply chain of power batteries, drive the development of the new-energy vehicle industry, and explore new business models, so as to achieve the environmental protection goal of carbon neutrality.