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

Jian Chen, Zhiyuan Tang, Yuan Huang et al.

William Yourey, Kayla Nong, Bhanu Babaiahgari

With the goal of increasing energy density in lithium–ion cells, new active materials continue to be developed and evaluated. Similarly, in commercial lithium–ion cells, inert materials present in manufactured cells should also be evaluated. The impact of the thickness of inert materials on EV-sized lithium–ion cells was evaluated. The impact of the thicknesses of the positive current collector, negative current collector, separator, and aluminum laminate package on cell properties is presented. The impact of these materials varies greatly over different cell designs, with one of the largest impacts being from a decrease in separator material thickness, especially in cells with a high number of electrode pairs, specifically, cells with a larger thickness or cells with low-capacity loadings. For high-capacity positive electrode loading, a decrease in separator thickness from 16 to 8 microns results in an increase in stack volumetric energy density from 502 to 531 Wh/L or an increase of 5.7%.

Zahra Hosseini, Haidar Samet, Masoud Jalil et al.

The incipient faults (IFs) in underground power cables (UPCs) are primarily caused by insulation failure in power cables, defects in splices, and water penetration. IF modeling is crucial for generating data under various conditions to ensure the performance and accuracy of algorithms in IF detection. This paper aims to establish and develop a robust yet practical model for IFs, utilizing real data. Practical records obtained from a laboratory are utilized in the process of identifying the models. Although many papers have been presented on arc modeling in other applications, none have been dedicated to modeling the IF in UPCs, except for two papers published by the authors of this paper. However, this paper presents the third model based on the time-varying property of the IF. This paper focuses on developing effective models based on Kopplin equations. Therefore, two modified Kopplin models are presented for modeling the IFs, and both proposed models demonstrate exemplary performance in modeling this fault. In the proposed models, the concept of time-varying coefficients is employed to illustrate the time-varying properties of IFs. Also, the new approach in this study, which utilizes the Levenberg-Marquardt algorithm, updates the model coefficients for each cycle. Finally, for robustness, the proposed models were evaluated using two error indices, which yielded low error indices. Since the model coefficients change in every cycle, to demonstrate their stochastic behavior, probability distribution functions (PDFs) were employed. Consequently, for every set of models’ coefficients, several PDFs are tested, and the PDF with the best match to real data is selected.

Daniela Galatro, Manav Shroff, Cristina H. Amon

This work presents an adaptive transfer learning approach for predicting the aging of lithium-ion batteries (LiBs) in electric vehicles using capacity fade as the metric for the battery state of health. The proposed approach includes a similarity-based and adaptive strategy in which selected data from an original dataset are transferred to a clean dataset based on the combined/weighted similarity contribution of feature and stress factor similarities and times series similarities. Transfer learning (TL) is then performed by pre-training a model with clean data, with frozen weights and biases to the hidden layer. At the same time, weights and biases toward the output node are recalculated with the target data. The error reduction lies between −0.4% and −8.3% for 20 computational experiments, attesting to the effectiveness and robustness of our adaptive TL approach. Considerations for data structure and representation learning are presented, as well as a workflow to enhance the application of transfer learning for predicting aging in LiBs.

Yu Shi, Haicheng Xie, Xinhong Wang et al.

Against the backdrop of automobile electrification, an increasing number of battery-swapping stations for electric vehicles have been launched to address the issue of slow battery charging under cold temperature conditions. However, due to the separation of the discharging and charging processes for lithium-ion batteries (LIBs) at swapping stations, and the circulation of batteries across different vehicles and stations, the operating data become fragmented, making it difficult to accurately identify the battery state-of-health (SOH). This study proposes a BiLSTM-Transformer framework that extracts the Constant Voltage Time (CVT) feature using only charging data, enabling the precise estimation of battery capacity degradation. Validation experiments conducted on battery samples under different operating temperatures showed that the model achieved a normalized RMSE of less than 1.6%. In ideal conditions, the normalized RMSE of the estimation reached as low as 0.11%. This model enables SOH estimation without relying on discharge data, contributing to the efficient and safe operation of battery swapping stations.

Oumaima Laguili, Julien Eynard, Marion Podesta et al.

The residential sector is energy-consuming and one of the biggest contributors to climate change. In France, the adoption of photovoltaics (PV) in that sector is accelerating, which contributes to both increasing energy efficiency and reducing greenhouse gas (GHG) emissions, even though the technology faces several issues. One issue that slows down the adoption of the technology is the “duck curve” effect, which is defined as the daily variation of net load derived from a mismatch between power consumption and PV power generation periods. As a possible solution for addressing this issue, electric water heaters (EWHs) can be used in residential building as a means of storing the PV power generation surplus in the form of heat in a context where users’ comfort—the availability of domestic hot water (DHW)—has to be guaranteed. Thus, the present work deals with developing model-based predictive control (MPC) strategies—nonlinear/linear MPC (MPC/LMPC) strategies are proposed—to the management of EWHs in individual dwellings equipped with grid-connected PV systems. The aim behind developing such strategies is to improve both the PV power generation self-consumption rate and the economic gain, in comparison with rule-based (RB) control strategies. Inasmuch as DHW and power demand profiles are needed, data were collected from a panel of users, allowing the development of profiles based on a quantile regression (QR) approach. The simulation results (over 6 days) highlight that the MPC/LMPC strategies outperform the RB strategies, while guaranteeing users’ comfort (i.e., the availability of DHW). The MPC/LMPC strategies allow for a significant increase in both the economic gain (up to 2.70 EUR) and the PV power generation self-consumption rate (up to 14.30%ps), which in turn allows the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>CO</mi><mn>2</mn></msub></mrow></semantics></math></inline-formula> emissions to be reduced (up to 3.92 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="normal">k</mi><mi mathvariant="normal">g</mi><mtext> </mtext><msub><mi>CO</mi><mrow><mn>2</mn><mo>.</mo><mi>eq</mi></mrow></msub><mrow><mo>)</mo></mrow></mrow></semantics></math></inline-formula>. In addition, these results clearly demonstrate the benefits of using EWHs to store the PV power generation surplus, in the context of producing DHW in residential buildings.

Lang Xu, Zhipeng Wang, Ya Li et al.

Copper (Cu) doping is recognized as an effective strategy to enhance the electrochemical properties of LiNi_1−x−yCo_xMn_yO₂ (NCM) cathode materials. However, the influence of Cu²⁺ doping on particle size and grain boundary fusion remains insufficiently explored. A simple microwave-assisted solution combustion synthesis method was used to introduce Cu²⁺ into LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523), aiming to regulate particle size and grain boundary fusion. The results demonstrate that increasing the Cu²⁺ doping content promotes particle growth, while an appropriate doping level reduces the degree of grain boundary fusion and cation mixing. Benefiting from these structural improvements, the optimized LiNi_0.5Co_0.2Mn_0.29Cu_0.01O₂ (Cu–1) cathode exhibits significantly enhanced electrochemical performance, delivering a discharge capacity of 128.6 mAh g⁻¹ after 100 cycles at 0.2 C, which is 32 mAh g⁻¹ higher than value of the undoped sample (96.6 mAh g⁻¹). These findings underscore that tailored Cu²⁺ doping can effectively optimize the microstructure of NCM523, leading to superior cycling stability, and provide new insights into the design of high-performance NCM cathodes.

Fan Gui, Zheng Guo, Xinrui Shan et al.

Marina Guindi, Rashad M. Kamel

Hyun Moo Hur, Jung Won Seo, Kyung Ho Moon et al.

We developed an electro-mechanical actuator for use as a steering device for railway vehicles. The specifications for a 50 kN-class electro-mechanical actuator capable of steering control for a sharp of a railway radius curve of up to 250 m, and with Direct Drive motor (DD motor) specifications, were derived as a power source to drive it. The DD motor and an electric mechanical steering actuator equipped with it were designed and a prototype was manufactured. As a result of testing laboratory tests on motor and actuator prototypes, all performance requirements were satisfied. We conducted a field test on the actuator prototype by installing it on a railway vehicle to verify the steering angle performance. The steering action of the actuator worked well when running in curved sections, and the steering angles measured for each curve were in line with the target steering angles. The mean error between the target steering angle and the measured steering angle was only 3.4%, indicating that the wheel steering action of the developed steering system was working very well. Therefore, the developed electro-mechanical actuator is expected to be fully utilized as a steering device for railway vehicles by meeting all the performance requirements of the steering system.

Yuan Chi, Yao Zou, Xinying Zheng et al.

The increasing wind power penetration and proliferation of induction motor loads, of which dynamic impact cannot be revealed through steady-state analysis, bring challenges to the short-term voltage stability of modern power systems. This study proposes a hybrid model-data-driven approach for dynamic VAR source planning to enhance the short-term voltage stability of wind-penetrated power systems to reduce the computation burden of electro-mechanical transient models. Firstly, the theoretical background of Stochastic Spectral Embedding (SSE) is introduced. Then, a surrogate model for the electromechanical transient model is established using SSE following efficient expansion coefficient calculation and a designed partition strategy for the studied problem. Furthermore, a hybrid model-data-driven VAR deployment optimization model is established with 3 objectives, which is solved by a dual-population-based evolutionary algorithm (DPEA). The accuracy and effectiveness of the model are verified on a modified New England 39-bus system. Simulation results prove that the computational cost is reduced significantly in comparison with conventional model-based method without a compromise in accuracy and the proposed method is also more accurate than methods based on other surrogate models. The proposed SSE-based model can be applied to other power system analysis with electro-mechanical transient models to alleviate the computational cost.

Lang Li, Lingfang Zheng, Wei Gao et al.

Charge transport materials constitute a relatively large portion of the cost in the production of perovskite solar cells (PSCs). Therefore, developing cheap and efficient charge transport materials is of great significance for the commercialization of PSCs. In this study, three low-cost hole transport materials (HTMs), specifically 4,4'-(3,3'-bis(4-methoxy-2,6-dimethylphenyl)-[2,2'-bithiophene]-5,5'-diyl)bis(N,N-bis(4-methoxyphenyl)aniline) (TP-H), 4,4'-(3,3'-bis(4-methoxy-2,6-dimethylphenyl)-[2,2'-bithiophene]-5,5'-diyl)bis(3-methoxy-N,N-bis(4-methoxyphenyl)aniline) (TP-OMe), and 4,4'-(3,3'-bis(4-methoxy-2,6-dimethylphenyl)-[2,2'-bithiophene]-5,5'-diyl)bis(3-fluoro-N,N-bis(4-methoxyphenyl)aniline) (TP-F), were designed and synthesized using a bulky group-substituted 2,2'-bithiophene core and methoxy- or F-functionalized triphenylamine derivatives. Compared to the HTMs without F atoms, TP-F using F substitution exhibited enhanced intermolecular packing, a lower highest occupied molecular orbital energy level, and increased hole mobility and conductivity. The PSC incorporating the doped TP-F as the hole transport layer achieved the highest power conversion efficiency (over 24%) among the three devices. The high performance of TP-F can be attributed to the passivation effect of S and F atoms on uncoordinated Pb2+ within the perovskite (PVSK) film, which significantly reduces the density of defect states and the incidence of trap-mediated recombination in PSCs. This study demonstrates the effectiveness of the 3,3'-bis(4-methoxy-2,6-dimethylphenyl)-2,2'-bithiophene building block for constructing cost-effective HTMs and highlights the impact of F substitution on enhancing the photovoltaic performance of PSCs.

Hong‐Jin Son, Jeemin Hwang, Min Young Choi et al.

Abstract This study explores a symmetric configuration approach in anion exchange membrane (AEM) water electrolysis, focusing on overcoming adaptability challenges in dynamic conditions. Here, a rapid and mild synthesis technique for fabricating fibrous membrane‐type catalyst electrodes is developed. Our method leverages the contrasting oxidation states between the sulfur‐doped NiFe(OH)2 shell and the metallic Ni core, as revealed by electron energy loss spectroscopy. Theoretical evaluations confirm that the S–NiFe(OH)2 active sites optimize free energy for alkaline water electrolysis intermediates. This technique bypasses traditional energy‐intensive processes, achieving superior bifunctional activity beyond current benchmarks. The symmetric AEM water electrolyzer demonstrates a current density of 2 A cm−2 at 1.78 V at 60°C in 1 M KOH electrolyte and also sustains ampere‐scale water electrolysis below 2.0 V for 140 h even in ambient conditions. These results highlight the system's operational flexibility and structural stability, marking a significant advancement in AEM water electrolysis technology.

Jianlin Li, Honghao You

Abstract This paper proposes a distributed cooperative control scheme for multiple energy storage unit (ESU) in DC microgrids to achieve the control objectives of SoC balancing, power sharing, and bus voltage recovery. In the primary control part, the proposed scheme constructs a control function between the SoC values of each ESU and the droop coefficients to dynamically adjust the droop coefficients. Through a communication network, information is exchanged with neighbouring ESUs to achieve SoC convergence. In the secondary control part, by exchanging power information with neighbouring ESUs, precise power distribution is achieved. Additionally, the proposed scheme maintains bus voltage stability. Finally, a DC microgrid simulation model and experimental platform were developed, demonstrating the feasibility and plug‐and‐play capability of the proposed control strategy through both simulation and experimental case tests.

Md. Robiul Islam, Maisha Islam, Tania Sarkar et al.

Tianchen Li, Xing Chen, Xieting Ni et al.

Anna Traupmann, Matthias Greiml, Josef Steinegger et al.

Abstract The high emission intensity of coal‐fired power plants (CFPP) leads to the inevitable next step towards energy transition, the coal phase‐out. One challenge is the subsequent use of still‐functioning assets. Re‐purposing these assets avoids value loss and creates new opportunities for coal regions. Therefore, this study considers the sector coupling technologies Power‐to‐Gas (PtG) and Gas‐to‐Power (GtP) as re‐purposing options. First, a multi‐variable Mixed‐Integer Linear Programming optimisation model is established. This model includes the participation of the plant in the current (2020) and future (2030, 2040) electricity and natural gas spot‐markets and the balancing power market while fulfilling existing contracts, and allows for determining the re‐purposing technologies' operating profiles. By applying a techno‐economic analysis, investment recovery periods of the considered re‐purposing technologies are assessed, which range between two (GtP) and over ten (PtG) years. A sensitivity analysis accounting for current energy prices and technological advancements reveals capital expenditure has the highest impact on this Return‐On‐Investment period. Additionally, a case study considering the Austrian energy grids is performed to account for the grid impact of integrating these technologies at former CFPP sites. Thus, it is found that the investigated sector coupling technologies have the potential to compensate for grid congestions even in profit‐optimised operation.

Wenting Chen, Yikun Yi, Feng Hai et al.

Ionic gel electrolyte retains the characteristics of non-volatilization, non-flammability and outstanding electrochemical stability of ionic liquid, and shows good electrochemical performance combined with the excellent characteristics of different matrix materials, which is considered to be the best choice to achieve high energy density and safety at the same time. In this paper, a flexible and self-healing ionic gel electrolyte was prepared using a solvent-assisted method based on a zteric ion (ZI) copolymer. Abundant hydrogen bonds and synergistic interaction of ions in the electrolyte system endowed it with remarkable self-healing ability. An ionic conductivity of 9.06 × 10⁻⁴ S cm⁻¹ at room temperature was achieved. Moreover, the lithium-ion transference number was increased to 0.312. The ionic gel electrolyte has a self-healing function which guarantees long-term tolerance during charging and discharging. The capacity retention rate of the Li//LiFePO₄ battery was 96% after 155 cycles at 0.1 C at 60 °C. This polymer electrolyte is expected to solve the problem of increasing polarization, which is caused by the low lithium ions migration number in ionic liquid electrolyte. And ultimately, it gave rise to a good rate performance.

Mario A. Mejia, Leonardo H. Macedo, Gregorio Muñoz-Delgado et al.

Tassneem Zamzam, Khaled Shaban, Ahmed Gaouda et al.