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10th Renewable Power Generation Conference, RPG 2021

作者： Wang, Qin Yao, Wei Fang, Jiakun Xu, Mengyao Ai, Xiaomeng Wen, Jinyu State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781839536069

With the growing proportion of photovoltaic (PV) generation in power systems, DC optimizers (DCOs) based distributed MPPT technologies are recently developed to mitigate the waste of solar energy due to the partial shadow in PV arrays. However, incorporating a large scale of PV capacity into power systems requires frequency regulation enhancement due to the reduced system inertia and PV power fluctuations. In this paper, a novel coordination control strategy for unit-level DCOs and grid-connected inverter is proposed to provide active frequency support from PV units. The proposed control scheme combines the f-P droop control for the power generation of PV-DCO units and the virtual inertia emulation for the DC-link capacitor of the voltage source inverter (VSI), to realize a communication-free cooperative control strategy between large-scale PV systems and grid systems. After that, a flexible power reserve for PV systems is achieved with the improvement of the rate of change of frequency (RoCoF), the frequency nadir, and the steady-state frequency deviation during under/over-frequency events in power systems. Case studies are performed to validate the effectiveness of the proposed control strategy. © The Institution of engineering and technology.

关键词： Solar energy

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Research on electron evolution of atmospheric pressure pulsed dielectric barrier discharge based on two-dimensional symmetrical fluid model

Research on electron evolution of atmospheric pressure pulse...

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2021 International Conference on Electrical engineering and Computer technology, ICEECT 2021

作者： Chen, Xingyu Lu, Chen Xiong, Zilan State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Hubei WuHan430074 China

In recent years, plasma technology under atmospheric pressure has been widely used, and it is urgent to study the mechanism of plasma microcosmic particles. With the development of computer technology, it may be a promising method to describe the microcosmic discharge process by simulation. In this study, a two-dimensional symmetrical fluid model of ns pulse dielectric barrier discharge (DBD) at atmospheric pressure was constructed using COMSOL software. The movement behavior of electrons in different working gas, different gap distance and different electrode radius was analyzed. It was found that in helium, the electrons would move to the outside electrode area with low electron density obviously. In argon, the electrons would always be mainly constrained within the electrode area, and the electron density is more than 105 times than that of the initial value. Changing the gap distance will change the diffusion rate and maximum density of electrons. The electron distribution will be more homogeneous, and the density within the electrode area will increase 102-103 times at large gap distance. Changing the electrode diameter has little impact on electron movement behavior. The validity of the model is verified by comparing experimental and simulated voltage and current waveforms. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Atmospheric pressure

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Redundant Strategy of T-Type DC/DC MMC Based on Third Harmonic Injection for Submodule Failure

Redundant Strategy of T-Type DC/DC MMC Based on Third Harmon...

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

作者： Pengfei Tang Dan Wang Hongyu Zhang Ruoxuan Fan Chengxiong Mao State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798331530174

ISBN: (纸本)9798331530181

In this paper, an endogenous AC optimization strategy for T-type topology DC/DC MMC(TDC-MMC) is proposed and applied to the protection strategy for sub-module faults. The endogenous AC model of TDC-MMC is established under the dq coordinate system. Based on this model, two endogenous AC strategies are derived under the conditions of loss minimization and voltage minimization, respectively. The optimization of endogenous AC is achieved by further introducing the third harmonic and redefining the voltage vector relationship under the minimum voltage condition. The optimal amplitude and phase of the third harmonic for each bridge arm are then determined. In a simulation of a 3 kV/1 kV DC transmission system, the working principle of the strategy is verified by applying the protection strategy to the sub-module fault cases of the HV Arm, MV Arm and LV Arm.

关键词： Simulation Bridge circuits Switches Minimization Harmonic analysis Transformers Vectors Topology Protection Optimization

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Highly luminescent zero-dimensional lead-free manganese halides forβ-ray scintillation

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Nano Research 2022年第9期15卷 8486-8492页

作者： Linyuan Lian Wei Qi Huaiyi Ding Hao Tian Qi Ye Yong-Biao Zhao Long Zhao Jianbo Gao Daoli Zhang Jianbing Zhang School of Optical and Electronic Information Huazhong University of Science and Technology1037 Luoyu RoadWuhan 430074China Hubei Key Laboratory of Bioinorganic Chemistry&Materia Medica School of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China Key Laboratory of Yunnan Provincial Higher Education Institutions for Optoelectronics Device Engineering School of Physics and AstronomyYunnan UniversityKunming 650504China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China Department of Physics and Astronomy Ultrafast Photophysics of Quantum Devices LaboratoryClemson UniversityClemsonSC 29634USA Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Shenzhen Huazhong University of Science and Technology Research Institute Shenzhen 518057China

Because of their moderate penetration power,β-rays(high-energy electrons)are a useful signal for evaluating the surface contamination of nuclear ***,the development ofβ-ray scintillators,which convert the absorbed high-energy electrons into visible photons,is hindered by the limitations of materials ***,we report two highly luminescent zerodimensional(0D)organic-inorganic lead-free metal halide hybrids,(C_(13)H_(30)N)_(2)MnBr_(4)and(C_(19)H_(34)N)_(2)MnBr_(4),as scintillators exhibiting efficientβ-ray *** hybrid scintillators combine the superior properties of organic and inorganic *** example,organic components that contain light elements C,H,and N enhance the capturing efficiency ofβparticles;isolated inorganic[MnBr_(4)]2−tetrahedrons serve as highly localized emitting centers to emit intense radioluminescence(RL)underβ-ray *** hybrids show a narrow-band green emission peaked at 518 nm with photoluminescence quantum efficiencies(PLQEs)of 81.3%for(C_(13)H_(30)N)_(2)MnBr_(4)and 86.4%for(C_(19)H_(34)N)_(2)MnBr_(4),*** enable the solution processing of this promising metal halide hybrid,we successfully synthesized(C_(13)H_(30)N)_(2)MnBr_(4)colloidal nanocrystals for the first *** excited byβ-rays,(C_(13)H_(30)N)_(2)MnBr_(4)scintillators show a linear response toβ-ray dose rate over a broad range from 400 to 2,800 Gy·s^(−1),and also display robust radiation resistance that 80%of the initial RL intensity can be maintained after an ultrahigh accumulated radiation dose of 240 *** work will open up a new route for the development ofβ-ray scintillators.

关键词： zero-dimensional metal halide hybrids radiation sterilization β-ray scintillation nanocrystals

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An Improved Crowbar Control Circuit of DFIG during LVRT 4

An Improved Crowbar Control Circuit of DFIG during LVRT

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4th IEEE China International Electrical and Energy Conference, CIEEC 2021

作者： Li, Jinxin Qiu, Qi Zhan, Meng State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology School of Electrical and Electronic Engineering Hubei China

ISBN: (纸本)9781728171494

In recent decades, the installed capacity of wind power is increased greatly, and doubly fed induction generator (DFIG) occupies a dominant position among wind power generators due to its excellent characteristics. However, how to improve the low voltage ride through (LVRT) success rate of doubly fed induction generator during the grid fault especially unsymmetrical grid fault of great value. Based on an improved crowbar control strategy, this paper designs a new control circuit, optimizes the control process, and improves its control speed. Finally, the simulation of MATLAB/Simulink shows that the rationality of this control circuit. © 2021 IEEE.

关键词： Timing circuits

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Flexible Scheduling Strategy Based on Situation Awareness technology under Extreme Weather Events

Flexible Scheduling Strategy Based on Situation Awareness Te...

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Energy, Electrical and Power engineering (CEEPE), International Conference on

作者： Shuhao Liang Suhua Lou Xun Yao Zheng Lin Xinrui Xiong State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China State Grid Gansu Electric Power Company Lanzhou China

ISBN: (数字)9798350375794

ISBN: (纸本)9798350375800

With the structural morphology evolution of the new power system paradigm, the emergence of random extreme weather events may lead to scenarios of low renewable energy power output and a sharp increase in load demand for a single day or multiple consecutive days, which seriously affect the power supply guarantee of the system. Perceiving the system’s extreme operation scenarios in advance and developing flexible scheduling schemes will help to enhance the system’s resilience. Firstly, based on the framework of the situation awareness technology, this paper proposes a physical-data co-driven model, including the sequential operation optimization model and convolutional neural network model, to explore the mapping relationship between the meteorological perception data and the system’s operation situation labels, realizing the advanced awareness of extreme operation risk scenarios. Secondly, a flexible scheduling strategy with variable balance periods is developed to optimize the system’s unit commitment and energy storage level, improving the system’s overall adaptation resilience and economic benefits. The case study demonstrates the superiority of the proposed model and strategy.

关键词： Economics Adaptation models Renewable energy sources Power supplies Optimization models Data models Robustness

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A Protection Scheme Based on the Current-limiting Reactor Voltage and its Derivation for MMC-MVDC 10

A Protection Scheme Based on the Current-limiting Reactor Vo...

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10th Renewable Power Generation Conference, RPG 2021

作者： Chen, Yiming Chen, Haotian Chen, Wei Jiang, Lang Yin, Xianggen State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781839536069

High-speed and reliable protection is the key to ensure safe operation of DC network. This paper raises a protection scheme based on the current-limiting reactor voltage and its derivation for MMC-MVDC. By analyzing the fault characteristics of MMC-MVDC network, a pick-up criterion based on the reactor voltage is proposed. Based on the different derivation of reactor voltage for pole-to-pole fault, and the different polarity of reactor voltage of two poles between internal and external fault, the protection criteria for internal-external distinguish are put forward. Using the variation of line voltage, the criterion of fault pole selection is realized. The proposed scheme is verified by a four-terminal DC network model. The operation conditions include different fault types, internal and external fault and various fault resistance are considered. The simulation results show that the proposed scheme can selectively and speedily remove all internal faults and it also has a good ability to overcome the effect of fault resistance. © The Institution of engineering and technology.

关键词： Poles

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Modeling of Electric Arc Furnace for Power Quality Analysis 3

Modeling of Electric Arc Furnace for Power Quality Analysis

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3rd IEEE China International Youth Conference on Electrical engineering, CIYCEE 2022

作者： Xu, Ruiyang Ma, Shaoxiang Zhang, Ming School of Electrical and Electronic Engineering China-EU Institute for Clean and Renewable Energy Huazhong University of Science and Technology International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430074 China

ISBN: (数字)9781665477321

ISBN: (纸本)9781665477321

Electric arc furnace (EAF) is one of the typical nonlinear loads in distribution network, which causes power quality problems such as harmonics and voltage flicker. In this paper, a time-domain simulation of AC EAF model for the research of power quality is established in MATLAB/Simulink and a simple multi-step parameter estimation method is proposed for a given EAF load. Considering the specific structure of EAF transformer, the arc model is obtained by combination and modification of classical Cassie and Mayr equations. The arc model is dynamically modulated by superimposing the sinusoidal and band-limited white noise signal to simulate the actual working conditions. The comparison between results from simulation and data from real measurement shows that the proposed model is capable of describing the time-varying, nonlinear and unbalanced characteristics of EAF accurately, which provides a reference for the research of the low-voltage side of the EAF transformer power quality problems. © 2022 IEEE.

关键词： Power quality

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Concept Design of BU for Mesh-like Constant Current Seafloor Observation Networks 2

Concept Design of BU for Mesh-like Constant Current Seafloor...

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2nd IEEE China International Youth Conference on Electrical engineering, CIYCEE 2021

作者： Fan, Peng Xu, Ying Ren, Li Tang, Yuejin Shi, Jing Li, Jingdong Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan China

ISBN: (纸本)9781665400640

Cabled undersea observation networks have been attracting increasing research attention due to the abilities of abundant power distribution and broad bandwidth communication. Stability of their power supply systems is crucial for their normal operation. However, rare studies were carried out on constant current (CC) mesh-like undersea observation networks. This paper focuses on designing branching unit (BU) for CC mesh-like seafloor observation network. Firstly, the design concept of CC mesh-like submarine power system is introduced, as well as the equivalent model of power delivery submarine cable and the circuit of CC converters. Then, based on features of the power network, concept of BU for mesh-like CC system is proposed respectively, and reliability protection schemes for various scenarios are analyzed. The model of the observatory network was set in MATLAB, Simulations were carried out, from which results showed good consistence, verifying the theoretical methods. © 2021 IEEE.

关键词： Submarines

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Evolution characteristics of vacuum arc plasma under two types of electrode structures based on the principle of two-colorimetric diagnosis

Evolution characteristics of vacuum arc plasma under two typ...

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IEEE International Conference on Plasma Science (ICOPS)

作者： S. Liu Z. Yuan L. Liu P. Ya L. Chen Y. Pan State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798350360912

ISBN: (纸本)9798350360929

The diffusion of vacuum arc directly affects the breaking ability of vacuum circuit breaker. The plasma distribution in the arc gap during initial diffusion is the main object to control the vacuum arc. The electrode structure is the main way to control the vacuum plasma by controlling the path of the current, so as to generate different magnetic fields to control the arc movement, development, distribution and extinction. Based on the principle of two-colorimetric diagnosis, the evolution characteristics of plasma under two types of electrode structures are experimentally studied. The 2D dynamic distributions of the plasma in the arcing with the cup-shaped axial magnetic field electrode and the $1 / 2$ turn coil electrode are obtained. The results show that the axial magnetic field intensity directly affects the distribution of cathode spots and plasma jets near the cathode. Compared with the cup-shaped axial magnetic field electrode, the luminance in arc gap presents a certain strip under the coil electrode condition, the overlap degree of the plasma jet decrease, the particle density is more uniform, and the attenuation rate along the radial direction is smaller, and is significantly reduced near the anode. The calculated results are in good agreement with the luminance distribution of spots and arc column.

关键词： Electrodes Coils Strips Plasma jets Circuit breakers Attenuation Plasmas

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