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Effects of resonant magnetic perturbations on the loss of energetic ions in tokamak pedestal

Plasma Science and technology 2020年第10期22卷 52-61页

作者： Haotian HUANG Lu WANG International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China

Resonant magnetic perturbations(RMPs) are extensively applied to mitigate or suppress the edge localized mode in tokamak plasmas, but will break the axisymmetric magnetic field configuration and increase the loss of energetic ions. The mechanism of RMPs induced energetic ion loss has been extensively studied, and is mainly attributed to resonant effects. In this paper,in the perturbed non-axisymmetric tokamak pedestal, we analytically derive the equations of guiding center motion for energetic ions including the bounce/transit averaged radial drift velocity and the toroidal precession frequency modified by strong radial electric field. The loss time of energetic ions is numerically solved and its parametric dependence is analyzed in *** find that passing energetic ions cannot escape from the plasma, while deeply trapped energetic ions can escape from the plasma. The strong radial electric field plays an important role in modifying the toroidal precession frequency and resulting in the drift loss of trapped energetic ions. The loss time of trapped energetic ions is much smaller than the corresponding slowdown time in DIII-D pedestal. This indicates that the loss of trapped energetic ions in the perturbed non-axisymmetric pedestal is important, especially for the trapped energetic ions generated by perpendicular neutral beam injection.

关键词： resonant magnetic perturbations non-axisymmetric magnetic field energetic ions drift loss radial electric field

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Detection and Imputation based Two-Stage Denoising Diffusion Power System Measurement Recovery under Cyber-Physical Uncertainties

arXiv

引用

arXiv 2023年

作者： Pei, Jianhua Wang, Jingyu Shi, Dongyuan Wang, Ping State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China Department of Electrical Engineering and Computer Science Lassonde School of Engineering York University Toronto Canada

Power system cyber-physical uncertainties, including measurement ambiguities stemming from cyber attacks and data losses, along with system uncertainties introduced by massive renewables and complex dynamics, reduce the likelihood of enhancing the quality of measurements. Fortunately, denoising diffusion models exhibit powerful learning and generation abilities for the complex underlying physics of the real world. To this end, this paper proposes an improved detection and imputation based two-stage denoising diffusion model (TSDM) to identify and reconstruct the measurements with various cyber-physical uncertainties. The first stage of the model comprises a classifier-guided conditional anomaly detection component, while the second stage involves diffusion-based measurement imputation component. Moreover, the proposed TSDM adopts optimal variance to accelerate the diffusion generation process with subsequence sampling. Extensive numerical case studies demonstrate that the proposed TSDM can accurately recover power system measurements despite renewables-induced strong randomness and highly nonlinear dynamics. Additionally, the proposed TSDM has stronger robustness compared to existing reconstruction networks and exhibits lower computational complexity than general denoising diffusion models. Copyright © 2023, The Authors. All rights reserved.

关键词： Electric power system measurement

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Realization of divertor configuration discharge in J-TEXT tokamak

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Plasma Science and technology 2022年第12期24卷 102-113页

作者： Zhipeng CHEN Lizhi ZHU Xin XU Wei ZHENG Ming ZHANG Li GAO Minghui XIA Jie YANG Mingchong ZHU Zhigang HAO Shaodong JIAO Zhifeng CHENG Zhoujun YANG Xiaoqing ZHANG Zhongyong CHEN Nengchao WANG Yonghua DING Ge ZHUANG Kenneth W GENTLE Yunfeng LIANG Yuan PAN the J-TEXT Team International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China Department of Engineering and Applied Physics School of Physical Sciences University of Science and Technology of ChinaHefei 230026People's Republic of China Institute for Fusion StudiesUniversity of Texas Austin TX 78712United States of America Forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung-PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)Jülich 52425Germany Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China

To extend the operation region of the Joint-Texas Experimental tokamak(J-TEXT) to the divertor configuration and even the H-mode,the divertor configuration discharge has been realized for the first time in the J-TEXT *** with the establishment of a power supply for the divertor configuration,the construction of relevant diagnostics,and the installation of the divertor target on the high-field side,divertor discharge has been *** the equilibrium calculation and position stability analysis,the control strategy has evolved to be more ***-density experiments and auxiliary heating experiments have been carried out on the divertor *** special midplane single-null(MSN) divertor configuration is shown to be more stable than the limiter configuration in the density limit condition and can reach a higher density in the *** the ECRH experiment,the power injection enhances the electron temperature and density,while more heat outflux is loaded on the divertor target tiles and causes more intensive recycling and impurity *** future plan for the divertor configuration operation in the J-TEXT tokamak is also included.

关键词： tokamak high-field side midplane single null divertor

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Fast Searching of Extreme Operating Conditions for Relay Protection Setting Calculation Based on Graph Neural Network and Reinforcement Learning

arXiv

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arXiv 2025年

作者： Li, Yan Wang, Jingyu Zhang, Jiankang Li, Huaiqiang Ren, Longfei Li, Yinhong Shi, Dongyuan Duan, Xianzhong The State Key Laboratory of Advanced Electromagnetic Technology The School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China The Northwest Branch State Grid Corporation of China Shaanxi Xian710048 China The College of Electrical and Information Engineering Hunan University Changsha China

Searching for the Extreme Operating Conditions (EOCs) is one of the core problems of power system relay protection setting calculation. The current methods based on brute-force search, heuristic algorithms, and mathematical programming can hardly meet the requirements of today’s power systems in terms of computation speed due to the drastic changes in operating conditions induced by renewables and power electronics. This paper proposes an EOC fast search method, named Graph Dueling Double Deep Q Network (Graph D3QN), which combines graph neural network and deep reinforcement learning to address this challenge. First, the EOC search problem is modeled as a Markov decision process, where the information of the underlying power system is extracted using graph neural networks, so that the EOC of the system can be found via deep reinforcement learning. Then, a two-stage Guided Learning and Free Exploration (GLFE) training framework is constructed to accelerate the convergence speed of reinforcement learning. Finally, the proposed Graph D3QN method is validated through case studies of searching maximum fault current for relay protection setting calculation on the IEEE 39-bus and 118-bus systems. The experimental results demonstrate that Graph D3QN can reduce the computation time by 10 to 1000 times while guaranteeing the accuracy of the selected EOCs. Copyright © 2025, The Authors. All rights reserved.

关键词： Deep reinforcement learning

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Iron Electrodeposition-Induced Degradation on Industrial Alkaline Water Electrolyzer: Multiphysics Model and Economic Analysis

SSRN

引用

SSRN 2024年

作者： Huang, Danji Wen, Qunlei Xiong, Binyu Lu, Ang Ai, Xiaomeng Zhong, Zhiyao Hu, Kewei Fang, Jiakun State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China School of Automation Wuhan University of Technology 122 Luoshi Road Hongshan District Hubei Wuhan430070 China

This paper investigates the performance degradation in industrial Alkaline Water Electrolyzers (AWE), with a focus on iron electrodeposition reaction (IER) as the primary degradation mechanism. This degradation mechanism is characterized by its impact on hydrogen evolution reaction (HER) materials and membrane porosity, leading to increased HER activation and membrane ohmic overpotential. A multiphysics model is developed to quantitatively assess the effects of IER on AWE performance. Experimental validation of the model demonstrates a predictive accuracy within ±3% relative error. The paper also includes a detailed economic analysis of various operational strategies, providing insights into optimizing the sustainability of industrial hydrogen production. This comprehensive approach offers valuable guidance for optimizing AWE systems in industrial applications. © 2024, The Authors. All rights reserved.

关键词： Economic analysis

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Self-correction in protoacoustic range verification for different proton pulse widths 2021

Self-correction in protoacoustic range verification for diff...

引用

2021 International Symposium on Biomedical engineering and Computational Biology

作者： Jiadong Li Ping Tan Lige Zhang State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology China TRIUMF Canada

ISBN: (纸本)9781450384117

In proton therapy, the acoustic waves produced by the proton radiation can be measured to determine the proton range. The k-Wave MATLAB toolbox is used to simulate the propagation process of pressure waves in time and space. By measuring the time-of-flight (TOF) of the pressure wave, the Bragg peak distance is obtained. In this study, we obtain the error maps for different pulse widths, which show that angle is the influencing factor of protoacoustic TOF range calculations. To reduce the systematic errors, the angle θ (θ is the angle between the proton beam direction and the vector passing Bragg peak and the sensor) is mapped to the systematic error using a fifth-order polynomial to obtain the correction factor, . The presented simulations show that by correcting the distance with , the systematic error of protoacoustic range verification can be controlled within 1mm under different proton pulses widths.

关键词： Protoacousctics Self-correction Proton therapy Regression analysis Range verification

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Simplified Time-Domain Design Methodology for LLC Resonant Converter in EV Charging Station Application

Simplified Time-Domain Design Methodology for LLC Resonant C...

引用

Power Systems and Electrical technology (PSET), IEEE International Conference on

作者： Ye Yuan Lin Xu Chuan Yao Jialing Yuan Xuehua Wang Xinbo Ruan State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan P. R. China Wuhan Second Ship Design and Research Institute Wuhan P. R. China

ISBN: (数字)9798350353204

ISBN: (纸本)9798350353211

LLC resonant converter featuring excellent soft-switching characteristic has been widely used in electric vehicle (EV) charging stations and other applications requiring isolated voltage conversion. The Fundamental Harmonic Approximation (FHA) model has been widely used in the field of resonant converter due to its simple and intuitive characteristics. When the switching frequency deviates from the resonant frequency, the method no longer maintains high accuracy. In this paper, a more accurate parameter design method based on the simplified time-domain model is proposed, considering the load characteristic of the charging stations. Finally, the simulation model verifies that the simplified design method has higher accuracy in predicting voltage gain. Meanwhile, the resonant tank parameters designed based on this method make the converter more efficient in situations where voltage and frequency vary across a wide range.

关键词： Accuracy Design methodology Switching frequency Resonant frequency Resonant converters Voltage Charging stations Electric vehicle charging Time-domain analysis Load modeling

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A differential protection scheme with inverter power based on pearson similarity

A differential protection scheme with inverter power based o...

引用

Tsinghua University-IET Electrical engineering Academic Forum: Constructing Green and Sustainable Energy System 2021

作者： Yao, Hao Xiong, Yuwei Xi, Wei Chen, Wei Electric Power Research Institute of China Southern Power Grid Guangzhou China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology School of Electrical and Electronic Engineering Wuhan China Electric Power Research Institute of China Southern Power Grid Guangzhou China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology School of Electrical and Electronic Engineering Wuhan China

ISBN: (纸本)9781839536199

The connection of inverter-type power supply to the distribution network makes the fault characteristics of the system when a short circuit occurs quite different from that of the traditional distribution network. Traditional current protection is no longer suitable for the distribution network with inverter-type power supply. Therefore, this article firstly analyses the output characteristics of the inverter-type power supply when the power grid fails, and analyses the difference in the positive sequence current waveforms at both ends of the line when a single-phase ground fault occurs in the grid-connected system with the inverter-type power supply from the perspective of phase. This paper uses waveforms to propose a differential protection principle based on Pearson similarity. The simulation results show that the protection principle can reliably identify internal and external faults, has the ability to withstand strong transition resistance, and can still be accurate in isolated network operation Identify the fault. Compared with cosine similarity, the protection criterion based on Pearson similarity has a stronger ability to distinguish time series differences, and this protection scheme has stronger engineering application value. © 2021 Institution of engineering and technology. All rights reserved.

关键词： Electric grounding

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Li4-xSbxSn1-xS4 solid solutions for air-stable solid electrolytes

引用

Journal of Energy Chemistry 2020年第2期29卷 171-176页

作者： Zhuoran Zhang Jianxing Zhang Yulong Sun Huanhuan Jia Linfeng Peng Yunyang Zhang Jia Xie State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringWuhan 430074HubeiChina State Key Laboratory of Materials Processing and Die & Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina

The sulfide solid electrolytes have the characteristics of high ionic conductivity and low grain boundary resistance, which make them suitable for bulk-type all-solid-state batteries. However, most of them suffer from poor stability in air. Here, we explore the air stable sulfide solid electrolytes in Li4-xSbxSn1-xS4 system. The solid solutions of Li4-xSbxSn1-xS4(0 ≤ x ≤ 0.5) can be formed in Li4-xSbxSn1-xS4 system. Li3.8 Sb0.2 Sn0.8 S4 achieves the highest ionic conductivity of 3.5 × 10-4 S cm-1 in this system,which is 5 times as that of Li4 Sn S4 and 3 orders of magnitude higher than that of Li3 Sb S4, respectively. Li3.8 Sb0.2 Sn0.8 S4 crystallizes into the same structure with high ionic conductivity phase of β-Li3 PS4. Moreover, Li3.8 Sb0.2 Sn0.8 S4 owns good stability in humid air. Matching with LiCoO2 and Li4 Ti5 O12,Li3.8 Sb0.2 Sn0.8 S4 exhibits the potential to be applied in all-solid-state batteries.

关键词： Solid electrolyte Air stable sulfide Li4SnS4,β-Li3PS4 All-solid-state battery

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Numerical Simulation of the Positive Stem during Dark Period in Long Air Gap Discharge

Numerical Simulation of the Positive Stem during Dark Period...

引用

2022 IEEE International Conference on High Voltage engineering and Applications, ICHVE 2022

作者： Liu, Yang Xiao, Pei Zhao, Xiangen Liu, Xiaopeng Wang, Xiankang Du, Yaping He, Junjia Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Wuhan430074 China State Grid Hunan Electric Power Company Hunan Changsha410007 China Hong Kong Polytechnic University Department of Building Environment and Energy Engineering Hong Kong999077 Hong Kong

ISBN: (数字)9781665407502

ISBN: (纸本)9781665407502

The stem evolution during the dark period is important for subsequent corona pulses or leader initiation. To this end, a physical model is built to simulate the stem evolution, in which the migration process of space charge and thermodynamic processes of the stem channel (heat conduction, heat convection and thermal diffusion) are both considered. The effect of voltage rise rate, electrode shape, and air pressure on the stem evolution during dark period is investigated. Results show that the space charge migration contributes to the stem elongation on the axial length and be more influential than thermodynamic processes at high voltage rising rates. Moreover, the stem elongation in the axial direction is more evident with a smaller curvature radius of the electrode tip. In addition, as the air pressure decreases, the central temperature of the stem channel rapidly decreases, and the heat dissipation is dominant. This study can help to further understand the characteristics of the dark period and its effect on subsequent discharges. © 2022 IEEE.

关键词： Heat conduction

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