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Forecasting Scenario Generation for Multiple Wind Farms Considering Time-series Characteristics and Spatial-temporal Correlation

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Journal of Modern Power Systems and Clean Energy 2021年第4期9卷 837-848页

作者： Qingyu Tu Shihong Miao Fuxing Yao Yaowang Li Haoran Yin Ji Han Di Zhang Weichen Yang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Electric Power Security High Efficiency Key Laboratory School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhanChina Department of Electrical Engineering Tsinghua UniversityBeijingChina

Scenario forecasting methods have been widely studied in recent years to cope with the wind power uncertainty problem. The main difficulty of this problem is to accurately and comprehensively reflect the time-series characteristics and spatial-temporal correlation of wind power generation. In this paper, the marginal distribution model and the dependence structure are combined to describe these complex characteristics. On this basis, a scenario generation method for multiple wind farms is proposed. For the marginal distribution model, the autoregressive integrated moving average-generalized autoregressive conditional heteroskedasticity-t (ARIMA-GARCH-t) model is proposed to capture the time-series characteristics of wind power generation. For the dependence structure, a time-varying regular vine mixed Copula (TRVMC) model is established to capture the spatial-temporal correlation of multiple wind farms. Based on the data from 8 wind farms in Northwest China, sufficient scenarios are generated. The effectiveness of the scenarios is evaluated in 3 aspects. The results show that the generated scenarios have similar fluctuation characteristics, autocorrelation, and crosscorrelation with the actual wind power sequences.

关键词： Scenario generation wind farm regular vine Copula spatial-temporal correlation time-series characteristics

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Using Deep Reinforcement Learning in Optimal Energy Management for Residential House Aggregators with Uncertain User Behaviors 7

Using Deep Reinforcement Learning in Optimal Energy Manageme...

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7th IEEE Student Conference on Electric Machines and Systems, SCEMS 2024

作者： Lin, Yujun Yan, Linfang Hui, Hongxun Chen, Yin Chen, Xia Wen, Jinyu School of Electrical and Electronic Engineering Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology Wuhan China City & Energy Research Institute Suzhou China University of Macau State Key Laboratory of Internet of Things for Smart City Department of Electrical and Computer Engineering China University of Strathclyde Department of Electronic and Electrical Engineering Glasgow United Kingdom

ISBN: (纸本)9798350366945

In this study, the home energy management problem, which can be regarded as a high-dimensional optimization problem, for numerous residential houses, is addressed. The concept of the aggregator is utilized to reduce the state and action space and to handle the high dimensionality. A two-stage deep reinforcement learning (DRL)-based approach is proposed for the aggregators to track the schedule from a superior grid and guarantee the operation constraints. In the first stage, a DRL control agent is set to learn the optimal scheduling strategy interacting with the environment based on the soft-actor-critic framework and generate the aggregate control actions. In the second stage, the aggregate control actions are disaggregated to individual appliances considering the users' behaviors. The uncertainty of an electric vehicle's charging demand is quantitatively expressed based on the driver's experience. An aggregate anxiety concept is introduced to characterize the driver's anxiety on the electric vehicle's range and uncertain events. Finally, simulations are conducted to verify the effectiveness of the proposed approach under dynamic user behaviors, and comparisons show the superiority of the proposed approach over other benchmark methods. © 2024 IEEE.

关键词： Deep reinforcement learning

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Magnetic diagnostics for magnetohydrodynamic instability research and the detection of locked modes in J-TEXT

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Plasma Science and technology 2021年第5期23卷 49-58页

作者： Dongliang HAN Chengshuo SHEN Nengchao WANG Da LI Feiyue MAO Zhengkang REN Yonghua DING 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

Magnetohydrodynamic(MHD)instabilities are widely observed during tokamak plasma *** diagnostics provide important information which supports the understanding and control of MHD *** paper presents the current status of the magnetic diagnostics dedicated to measuring MHD instabilities at the J-TEXT tokamak;the diagnostics consist of five Mirnov probe arrays for measuring high-frequency magnetic perturbations and two saddle-loop arrays for low-frequency magnetic perturbations,such as the locked *** recent years,several changes have been made to these *** structure of the probes in the poloidal Mirnov arrays has been optimized to improve their mechanical strength,and the number of in-vessel saddle loops has also been improved to support better spatial *** to the installation of high-field-side(HFS)divertor targets in early 2019,some of the probes were removed,but an HFS Mirnov array was designed and installed behind the *** to its excellent toroidal symmetry,the HFS Mirnov array has,for the first time at J-TEXT,provided valuable new information about the locked mode and the quasi-static mode(QSM)in the ***,various groups of magnetic diagnostics at different poloidal locations have been systematically used to measure the QSM,which confirmed the poloidal mode number m and the helical structure of the *** including the HFS information,the 2/1 resonant magnetic perturbation(RMP)-induced locked mode was measured to have a poloidal mode number m of~2.

关键词： J-TEXT tokamak locked mode magnetic diagnostics magnetohydrodynamic instabilities

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In Situ Coupling of Highly Dispersed Ni/Fe Metal-NC Sites and N-Doped 3D Carbon Fibers Toward Free-Standing Bifunctional Cathode for Flexible Zinc-Air Battery

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Energy & Environmental Materials 2024年第1期7卷 121-130页

作者： Chenglong Lai Mengjun Li Yi Shen Min Zhou Wei Wang Kai Jiang Haomiao Li Kangli Wang State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhanHubei 430074China Engineering Research Center of Power Safety and Efficiency Ministry of EducationWuhanHubei 430074China

Designing flexible free-standing air-electrode with efficient OER/ORR performance is of vital importance for the application of Zinc-air batteries in flexible ***,a flexible free-standing electrode(Ni/Fe-NC/NCF/CC)is synthesized by in-situ coupling of binary Ni/Fe-NC nanocubes and N-doped carbon nanofibers(NCF)rooted on carbon *** highly dispersed binary Ni/Fe-NC sites ensure excellent ORR activity and create efficient OER active sites relative to Ni-NC and *** in-situ coupling of Ni/Fe-NC and NCF constructs a 3D interconnected network structure that not only provides abundant and stabilized reactive sites but also guarantees fast electron transfer and gas transportation,thus achieving efficient and fast operation of ORR/***,Ni/Fe-NC/NCF/CC displays a much positive potential(0.952 V)at 4.0 mA cm^(-2)for ORR and a low OER overpotential(310 mV)at 50 mA cm^(-2).The Zinc-air battery with Ni/Fe-NC/NCF/CC air-electrode exhibits excellent battery performance with outstanding discharge/charge durability for 2150 *** flexible Zn-air batteries with foldable mechanical properties display a high power density of 105.0 mW cm^(-2).This work widened the way to prepare flexible bifunctional air-electrode by designing composition/structure and in-situ coupling.

关键词： binary Ni/Fe-NC sites in-situ coupling synergistic catalytic effect Zn-air battery

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Thermal Balance-Based Evaluation Method for Safe Operating Areas and Its Degradation of IGBT Power Module

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IEEE Journal of Emerging and Selected Topics in Power Electronics 2025年

作者： Han, Tongyao Luo, Yifei Liu, Binli Yuan, Hao Shi, Zenan Naval University of Engineering National Key Laboratory of Electromagnetic Energy China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430033 China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University Xi’an710049 China

Insulated gate bipolar transistors (IGBTs) power module experience significant thermal stress during short-time overload conditions, and their electro-thermal characteristics exhibit strong nonlinearities. As a result, the two-dimensional safe operating area (SOA) provided in the datasheet is unable to meet the need of device reliability assessments. In this paper, we propose a quantitative assessment method based on the thermal balance principle to define the SOA for IGBTs and assess its degradation. A three-dimensional SOA that incorporates voltage, current, and junction temperature is established to prevent IGBT from thermal failures. The proposed SOA indicates that IGBT can operate safely at more than twice the rated current, and the junction temperature can exceed 448.15K(175° C) without thermal failures. This work provides theoretical support for IGBT application design and reliability assessment. According to the physical mechanisms associated with thermal failures of IGBT power module, a criterion to characterize the thermal instability of devices is established. Further, the net heat flux analysis model that integrates semiconductor physics with heat conduction theory is established, enabling the formulation of the three-dimensional SOA of IGBT. Moreover, the effects of the degradation of electro-thermal characteristics on the SOA throughout the long-term operation of the device is considered. In addition, an electro-thermal coupling model that simulates the electro-thermal characteristics of the device is established. The results from both simulation and experiment demonstrate that the established SOA and its degradation effectively predict the reliability of the IGBT under short-time overload conditions. © 2013 IEEE.

关键词： Insulated gate bipolar transistors (IGBT)

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Transient Process Analysis of Grid-Forming Converter under Severe Voltage Sags with Different Q-V Controllers 2

Transient Process Analysis of Grid-Forming Converter under S...

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2nd Asia Power and Electrical technology Conference, APET 2023

作者： Xie, Chenyang Lin, Xinchun Sun, Huiqiang Zhang, Jiayan Wei, Juntian Fang, Tianyu Liu, Dan Jiang, Kezheng Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China Electric Power Research Institute State Grid Hubei Electric Power Co. LTD Wuhan China

ISBN: (纸本)9798350359428

Grid-forming VSCs based on Virtual Synchronous Generator (VSG) control strategy provide primary frequency regulation and voltage support for weak grids or VSC-dominated grids. Analyzing the transient stability of VSG-VSCs under large disturbances is useful for maintaining the security of the grid. However, different control strategies in grid-forming converters will cause the VSC to operate at different transient processes, and this topic is little studied. In this paper, the impacts of Q-V controller on transient process under severe voltage drops are elaborately studied. In particular, it is shown that the change of controller will change the transient process of the VSC, which impacts the transient stability of VSG-VSCs. Simulations verify the validity of the transient stability analysis. © 2023 IEEE.

关键词： Controllers

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Small-Signal Stability Analysis of Parallel Grid-Connected System with Grid-Forming Converter and Grid-Following Converter

Small-Signal Stability Analysis of Parallel Grid-Connected S...

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Electrical engineering (CIYCEE), IEEE China International Youth Conference on

作者： Xiayan Li Changsong Chen Lin Gan Chenxi Bai Taihang He State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798331530174

ISBN: (纸本)9798331530181

In order to guarantee the stable operation of new energy sources when connected to the power system through converters, it is of paramount importance to conduct thorough research the small-signal stability of parallel grid-connected system with grid-forming converter (GFM) and grid-following converter (GFL). Initially, the state-space small-signal model of the parallel grid-connected system with GFM and GFL are derived. Subsequently, the impact of the phase-locked loop (PLL) bandwidth, virtual inertia, and reactive power loop integral coefficient on system stability is assessed using the eigenvalue locus method. Moreover, the participation factor analysis method is employed to identify the dominant state variables of the oscillatory mode. Finally, the correctness of the theoretical analysis is validated using PLECS.

关键词： Reactive power Grid following Bandwidth Power system stability Stability analysis Eigenvalues and eigenfunctions Circuit stability Phase locked loops Integrated circuit modeling Grid forming

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Improvement of stability and solid-state battery performances of annealed 70Li_(2)S–30P_(2)S_(5) electrolytes by additives

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Rare Metals 2022年第1期41卷 106-114页

作者： Hao-Tian Ren Zi-Qi Zhang Jun-Zhao Zhang Lin-Feng Peng Zhen-Yuan He Ming Yu Chuang Yu Long Zhang Jia Xie Shi-Jie Cheng State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China Clean Nano Energy Center State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China School of Physics Huazhong University of Science and TechnologyWuhan 430074China Wuhan National High Magnetic Field Center and School of Physics Huazhong University of Science and TechnologyWuhan 430074China

The replacement of liquid electrolyte with solid electrolyte can significantly improve the safety and power/energy density of lithium batteries.70Li_(2)S–30P_(2)S_(5) is one of the most promising solid electrolytes with high conductivity for solid–state *** this work,the ionic conductivity and stability toward moisture and lithium metal of 70Li_(2)S–30P_(2)S_(5) were enhanced by introducing the different amounts of Li_(2)O additives.65Li_(2)S–30P_(2)S_(5)–1%Li_(2)O delivered the highest conductivity,while 65Li_(2)S–30P_(2)S_(5)–5%Li_(2)O showed the best moisture stability and improved lithium ***-state batteries using 65Li_(2)S–30P_(2)S_(5)–5%Li_(2)O electrolyte and high-voltage LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2) cathode exhibited low initial discharge capacity(100 mAh·g^(-1))and Coulombic efficiency(69%).Li_(3)InCl_(6) electrolytes were introduced both in the cathode mixture to replace sulfide electrolyte and in the interface layer to improve the cathode compatibility for the solid-state batteries,showing enhanced discharge capacity(175 mAh·g^(-1))and improved initial Coulombic efficiency(86%).Moreover,it also exhibited good performance at-20℃.

关键词： Solid electrolyte 70Li2S–30P2S5 Stability Additives Solid-state batteries

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Characterization of on-state resistance of electrically triggered vacuum surface flashover switch

Characterization of on-state resistance of electrically trig...

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Electrical engineering and Control Science (IC2ECS), International Conference on

作者： Yingjie Fu Luokang Dong Mengbing He Zhengzheng Liu The State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798331510107

ISBN: (纸本)9798331510114

Electrically triggered Vacuum Surface Flashover Switches (VSFS) are suitable for high voltage and high power conversion applications because of their advantages of high turn-on speed, high insulation recovery speed, small size, and simple structure. Low on-state resistance, which determines the output efficiency of the pulsed power system and its own lifetime, is an important index of high-performance VSFS. In this paper, the variation rule of the on-state resistance of VSFS under square wave current condition and exponential decay current condition and the influencing factors are investigated by experiment. The experimental results show that in the on-state stage, the operating voltage has a greater effect on the VSFS on-state resistance, and the trigger energy have a smaller effect on the VSFS on-state resistance.

关键词： Electrical engineering Insulation Surface waves Surface resistance High-voltage techniques Flashover Market research Power conversion Voltage control Pulsed power systems

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The Impact Analysis of Line Inductance on System Amplitude and Frequency Stability in the Converter Interfaced System

The Impact Analysis of Line Inductance on System Amplitude a...

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International Conference on Power and Energy technology (ICPET)

作者： Qiumeng Xu Sicheng Wang Xiaoming Yuan State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798350375855

ISBN: (纸本)9798350375862

With the transition to cleaner energy sources, a high proportion of renewable devices often needs to be connected to the grid through long transmission lines, which increases the risk of system instability. The system is composed of device and network, both of which have influence on system stability. The impact of device control parameters on system stability has been widely studied, but the impact of network on system stability should not be overlooked. This paper focuses on the line inductance in the network. Firstly, it elucidates the implications of the system Amplitude and Frequency (A&F) stability, considering the dynamic characteristics of both device and the network. Secondly, it analyzes the high-order dynamic characteristics of the inherent relationship between the excitation of the amplitude/frequency of internal voltage and the response of active/reactive current, under the constraints imposed by line inductance in the network. This analysis reveals the essence of the dominant feature of this relationship, which is influenced by the system oscillation frequency. Finally, the system oscillation frequency was analyzed through closed-loop simulation, which affects the A&F stability of the system by affecting the energy storage capacity of the line inductance. This paper establishes a general understanding of the energy storage capacity of line inductor in the grid and lays the foundation for further understanding and analyzing of the mechanism of power system instability problems.

关键词： Inductance Renewable energy sources Power transmission lines Power system dynamics Voltage Power system stability Stability analysis Inductors Oscillators Energy storage

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