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2022 IEEE International Conference on Power Systems and Electrical technology, PSET 2022

作者： Cheng, Siyuan Dong, Manling Shi, Xi Guo, Lei Yao, Wei Wang, Wei Ma, Yunrui Corporation Research Institute State Grid Henan Electric Power Zhengzhou China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781665489157

With the development of ZnO arresters towards high voltage gradient and miniaturization, more stringent requirements are put forward for ZnO varistor ceramics, and higher requirements are also placed on the uniformity of the distribution of added components in ZnO varistor ceramic powders. this paper, ZnO varistor powders were prepared by the chemical precipitation method, and ZnO varistor ceramics were prepared at different sintering The properties of the samples were analyzed by various characterization methods, and their microstructure and electrical properties were studied. The experimental findings indicate that the mean grain size of ZnO varistor ceramics become larger as the sintering temperature increases, and the grain boundary nonlinearity coefficient and potential barrier height first increase and then decrease. When the sintering temperature is 1050°C, the grain size of the ZnO varistor ceramic sample is better, the grain boundary barrier height is the highest, and the comprehensive electrical properties are better. Compared with the common 1100°C~1200°C in the literature, it not only reduces the energy consumption but also improves the performance of ZnO varistor ceramics. It is speculated that the uniform distribution of doping ions before sintering reduces the sintering temperature. The lower temperature reduces the volatilization of oxide additives such as bismuth oxide and avoids abnormal grain growth. © 2022 IEEE.

关键词： Sintering

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Discussion of Third Harmonic Voltage Characteristics of Large Hydro Generator Stator Winding and Improvement of Ground Protection 1

Discussion of Third Harmonic Voltage Characteristics of Larg...

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2022 1st International Conference on Advances in Modern Physics Sciences and engineering technology, ICPSET 2022

作者： Tan, Liming Wang, Yikai Feng, Xiaosong Zhang, Chunhui Yin, Xianggen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan430074 China Technology and Research Center Yangtze Power Co. Ltd Yichang443002 China

Large hydro-generators require a 100% protected area for stator ground protection. Because the fundamental voltage criterion has low sensitivity near the neutral point, a high sensitivity third harmonic voltage criterion is needed to ensure that the generator can accurately respond to stator ground fault. This paper analyzes the third harmonic voltage characteristics of two large hydro-generators, calculates the sensitivity of the existing third harmonic criterion, and points out that the impedance parameters of the grounding transformer should be considered. In view of the lack of sensitivity of the third harmonic criterion for large hydro-generators, this paper proposes a stator ground protection criterion based on the third harmonic voltage variation, which has zero action quantity under the generator non-fault conditions and zero braking quantity after a ground fault occurs, and thus has high sensitivity and can effectively respond to high-resistance ground faults. PSCAD/EMTDC simulation results show that the proposed method has high sensitivity at different fault locations and transition resistances, which can provide theoretical support for the improvement of stator grounding protection in practical engineering. © Published under licence by IOP Publishing Ltd.

关键词： Sensitivity analysis

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Study on High Voltage Pulse Driven Air Plasma Interaction with NH3 through Direct/Indirect Manner 4

Study on High Voltage Pulse Driven Air Plasma Interaction wi...

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

作者： Zhu, Yu Zou, Zhenping Xiong, Zilan Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781728171494

Removal or reuse of wasted NH3 by cold atmospheric plasma has great potential in industry and green agricultural and is benefit for energy saving and environment protection. This study investigated the interaction between pulse driven air plasma and gaseous NH3 through a direct and an indirect manner. A pin-pin discharge device was used. The gas phase products of direct reaction and indirect reaction of plasma and NH3 were compared and analyzed. It was found that double nitrogen fertilizer NH4NO3 could be formed during the indirect reaction manner while NH3 was decomposed by the direct reaction manner. Fourier transform infrared (FTIR) spectroscopy was used to measure the gas phase products. The concentration of NO, NO2 and NH3 vs. time was calculated to illustrate the chemical process inside the reaction chamber. The optical emission spectrum (OES) of discharging in different gas or gas mixture were recorded and the plasma temperature was fitted by using the spectrum of the N2 second positive system. The steady state temperature profile inside the reaction chamber during the discharge was also simulated. Finally, the possible reactions mechanisms during the direct and indirect reaction process were discussed. © 2021 IEEE.

关键词： Fourier transform infrared spectroscopy

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In Situ High-performance Gel Polymer Electrolyte with Dual-reactive Cross-linking for Lithium Metal Batteries

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Energy & Environmental Materials 2024年第1期7卷 51-59页

作者： Fuhe Wang Honghao Liu Yaqing Guo Qigao Han Ping Lou Long Li Jianjie Jiang Shijie Cheng Yuancheng Cao School of Materials Science and Engineering Huazhong University Huazhong University of Science and Technology Wuhan 430074China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and TechnologyWuhan 430074China State Grid Huzhou Power Supply Company Huzhou 313000China Huzhou Electric Power Design Institute Company Huzhou 311404China

Lithium metal batteries have been considered as one of the most promising next-generation power-support devices due to their high specific energy and output ***,the uncontrollable side-reaction and lithium dendrite growth lead to the limited serving life and hinder the practical application of lithium metal ***,a tri-monomer copolymerized gel polymer electrolyte(TGPE)with a cross-linked reticulation structure was prepared by introducing a cross-linker(polyurethane group)into the acrylate-based in situ polymerization *** soft segment of polyurethane in TGPE enables the far migration of lithium ions,and the-NH forms hydrogen bonds in the hard segment to build a stable cross-linked *** system hinders anion migration and leads to a high Li^(+)migration number(t_(Li^(+))=0.65),which achieves uniform lithium deposition and effectively inhibits lithium dendrite *** a result,the assembled symmetric cell shows robust reversibility over 5500 h at a current density of 1 mA cm^(-2).The LFP∷TGPE∷Li cell has a capacity retention of 89.8%after cycling 800 times at a rate of *** summary,in situ polymerization of TGPE electrolytes is expected to be a candidate material for high-energy-density lithium metal batteries.

关键词： gel polymer electrolytes hydrogen bonds in situ polymerization lithium metal batteries polyurethane

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Short-Circuit Current Calculation Method for Power System with Renewable Energy Source and HVDC System 5

Short-Circuit Current Calculation Method for Power System wi...

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5th IEEE Conference on Energy Internet and Energy System Integration, EI2 2021

作者： Wang, Yuxi Qian, Kun Wen, Minghao State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781665434256

The short-circuit currents characteristics of renewable energy source (RES) and high voltage direct current (HVDC) system are different from the short-circuit currents characteristics of traditional synchronous generator (SG). According to the fault-ride-through (FRT) requirements of different types of RES, the steady-state short-circuit currents calculation models of doubly-fed induction generator (DFIG) and inverter-interface renewable energy source (IIRES) such as photovoltaic (PV) and direct-drive permanent magnetic synchronous generator (D-PMSG) are built in this paper. Based on the converter switching function model and the HVDC control system, the calculation model of HVDC system steady-state short-circuit currents is built. Combined with RES and HVDC system short-circuit currents calculation models, a short-circuit currents calculation method for power system with multiple types RES and HVDC under ac power system fault is proposed. Finally, the effectiveness of the proposed method of short-circuit currents calculation is verified by simulation cases. © 2021 IEEE

关键词： Synchronous generators

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Analysis and Experiment of Homopolar Inductor Alternator With an Active Compensated Winding in Capacitor Charging Power Supply System

Analysis and Experiment of Homopolar Inductor Alternator Wit...

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作者： Guo, Songlin Yu, Kexun Yi, Zhengkang Lai, Houchuan Xie, Xianfei The State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China The Beijing Aerospace Automatic Control Institute Beijing100854 China The Southwest Institute of Technical Physics Chengdu610041 China

Homopolar inductor alternator (HIA) typically plays a key role in the capacitor charging power supply (CCPS) system. However, HIA cannot meet the growing demand for higher power density due to its unipolar magnetic field. In order to obtain a compact HIA-CCPS with higher power density, a novel HIA named ACWHIA based on the active compensation theory is proposed in this article, by adding an active compensated winding (ACW) in the traditional HIA. The main function of ACW connected in series in the DC charging circuit, is to increase the machine's transient voltage for improving the system's power density. It is absolutely different from most of the existing pulsed alternators with compensated windings, whose theory is to reduce the transient inductance to increase the power density. In this article, the influence of the transient voltage on the charging performance is first analyzed. Second, the scheme and operating principle of ACWHIA are proposed. Third, the electromagnetic characteristics of the machine and the model of ACWHIA-CCPS are analyzed in detail by theoretical analysis. Then, a simplified model of the ACWHIA-CCPS system is proposed, and this model simplifies the analysis and shows the operating principle of the active compensation winding. Finally, a platform of ACWHIA is developed and the experiments are carried out. The results indicate that the novel machine can be an attractive choice to improve the power density of HIA-CCPS. © 2023 IEEE.

关键词： Winding

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Fine Tune or not? Evaluation of Transfer Methods for Power System Transient Stability Analysis

Fine Tune or not? Evaluation of Transfer Methods for Power S...

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2021 International Conference on Power System technology, POWERCON 2021

作者： Li, Zhouping Yao, Wei Huang, Yanhao Shi, Zhongtuo Tang, Yong Wen, Jinyu Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781665407373

Many methods based on deep learning (DL) have been developed to handle the power system stability analysis problem with satisfactory results. A well-trained DL model on the source domain may encounter the performance reduction problem when applied to a target domain of different distributions. Thus, transfer learning is needed to transfer knowledge learned from the source domain to the target domain which can reduce the cost of collecting more data and labels. As a commonly used scheme, fine-tuning is thought to be able to share the ability to extract high-level features to the target model by reusing the parameters of the pretrained model. Several fine-tune schemes are compared to evaluate the benefits brought by fine-tuning. The results show that freezing the layers of the DL model may restrict the tuning process in terms of convergence speed and test accuracy. A simple but effective mixed dataset training scheme is demonstrated to work better than fine-tune schemes. © 2021 IEEE.

关键词： Deep learning

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A Digital Processing Method of MSK Signal Based on ADC 3

A Digital Processing Method of MSK Signal Based on ADC

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

作者： Lou, Hangchuan Wu, Xianglong Tu, Junyao Long, Gen Liu, Hengyang Kong, Wubin School of Electrical and Electronic Engineering Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan430074 China Wuhan Maritime Communication Research Institute Wuhan430010 China

ISBN: (数字)9781665477321

ISBN: (纸本)9781665477321

A digital processing method of the minimum shift keying (MSK) excitation signal is proposed for cascaded power amplifiers with phase shift control. Through the mathematical characteristics of MSK signal, the frequency extraction of MSK excitation signal and the accurate judgment of code conversion time are realized by Analog-to-digital converter (ADC). To avoid the accumulation of errors in frequency detection, a comparator is used at the beginning of each cycle to calibrate the inverter output signal and MSK excitation signal. Compared with traditional analog method, the proposed method is realized by ADC, which has the advantages of simple structure, high precision, and high waveform reduction Simulation models of digital and analog extraction method are constructed, indicating that the method has the advantages of accurately judging the code conversion time and extracting the frequency. The method can realize the digital processing of MSK signal and generate the control signal of cascaded power amplifiers with phase shift control. © 2022 IEEE.

关键词： Power amplifiers

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Research on Active Current-Limiting Control and Fault Characteristics of DC Distribution Network 6

Research on Active Current-Limiting Control and Fault Charac...

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6th Asia Conference on Power and Electrical engineering, ACPEE 2021

作者： Ran, Qisheng Zhang, Zhe Han, Jiexiang Yin, Xianggen Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781728191591

The DC distribution network based on the hybrid modular multilevel converter (MMC) has the ability of active current-limiting control, which plays an active role in fault clearing of distribution network. However, the fault characteristics of the DC distribution network become complicated because of the active current-limiting control. It brings new problems to the fault detection and judgment of relay protection. According to the structural features of the hybrid MMC, the start-up strategy and control objectives of the active current-limiting control are analyzed in this paper. The improvement suggestions are put forward to maintain the operational safety of the power grid, as well as meet the application requirements of the relay protection. Moreover, The characteristics of the short-circuit current of the DC distribution network are analyzed based on the active current-limiting control. Meanwhile, the influences on the relay protection are estimated. Finally, the effectiveness of the proposed current-limiting control strategy and the correctness of the fault characteristic analysis results are verified by simulation tests. © 2021 IEEE.

关键词： Relay protection

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Launch Efficiency of Capacitive Energy-Storage electromagnetic Railgun System

Launch Efficiency of Capacitive Energy-Storage Electromagnet...

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Pulsed Power Conference, International Conference on High-Power Particle Beams and International Symposium on electromagnetic Launch technology (EAPPC/BEAMS/EML), Euro-Asian

作者： Tingyun Xiao Lixue Chen Xuan Xu Shengqin Xu Wenhao Zhang Bingxuan Zhao State Key Laboratory of Advanced Electromagnetic Technology Key Laboratory of Pulsed Power Technology Ministry of Education School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9789038661353

ISBN: (纸本)9798350352733

electromagnetic railgun have high initial velocity, long range and other advantages. Improving the launch efficiency is one of the most important needs for the application of electromagnetic rail launch technology. Based on the subsystem models of pulse power supply, rail and armature of railgun, the equivalent circuit mathematical model of the electromagnetic rail gun system under lumped parameters is established. The effects of capacitance, voltage, inductance, resistance and acceleration distance on the system efficiency were simulated and analyzed. The results of the study are of great significance in guiding the design of the electromagnetic launch system.

关键词： Rails Resistance Performance evaluation Pulsed power supplies Power supplies electromagnetic scattering Railguns Mathematical models electromagnetics Integrated circuit modeling

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