检索结果-南通市图书馆

state Key Laboratory of Power grid Safety and Energy Conservation,China Electric Power research institute,Beijing,China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2022年第3期8卷 710-720页

作者： Lin Yu Huadong Sun Shiyun Xu Bing Zhao Jian Zhang state Key Laboratory of Power grid Safety and Energy Conservation China Electric Power Research InstituteBeijing100192China

The power system is experiencing a higher penetration of renewable energy generations(REGs).The short circuit ratio(SCR)and the grid impedance ratio(GIR)are two indices to quantify the system strength of the power system with *** this paper,the critical short circuit ratio(CSCR)is defined as the corresponding SCR when the system voltage is in the critical stable *** static voltage stability analysis,the mathematical expression of the CSCR considering the impact of GIR is *** maximum value of CSCR is adopted as the critical value to distinguish the weak power *** on the static equivalent circuit analysis,it is proved that the CSCR is still effective to evaluate critical system strength considering the interactive impact among ***,we find that the GIR can be neglected and the SCR can be used individually to evaluate the system strength when SCR>2 or GIR>*** correctness and rationality of the CSCR and its critical value are validated on ADPSS.

关键词： Critical short circuit ratio critical value grid impedance ratio maximum power transfer theorem static equivalent circuit analysis

Impedance Analysis of grid Forming Control Based Modular Multilevel Converters

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2023年第3期11卷 967-979页

作者： Rongcai Pan Guangfu Tang Shan Liu Zhiyuan He China Electric Power research institute Beijing 100192China state grid smart grid research institute Beijing 102209China

grid-forming control(GFC)is promising for power electronics based power systems with high renewable energy ***,the impedance modeling for GFC is necessary and has gained significant attention ***,most of the impedance analyses for GFC are based on a twolevel converter(TLC)rather than a modular multilevel converter(MMC).MMC differs from TLC with respect to its dominant multi-frequency *** is necessary to analyze the impedance of GFC-based MMC owing to its superiority in highvoltage direct current(HVDC)transmission to interlink two weak AC systems with high renewable energy *** the main contribution,this paper presents the AC-and DC-side impedance analyses for the GFC-based MMC with both power and DC voltage control using the harmonic transfer function(HTF),and compares the impedances of GFC-based MMC and *** is inferred that although the impedance is mainly influenced within 200 Hz,the instability still could occur owing to negative resistance triggered by relatively larger *** difference in AC-side impedance with power and DC voltage control is not apparent with proper parameters,while the DC-side impedance differs *** generalized Nyquist criterion is necessary for AC-side stability owing to the relatively large coupling terms under ***,the coupling between AC-and DC-side impedances is noneligible,especially considering the DC-side resonance around the system resonant *** effects of parameters,system strength,and virtual impedance on the impedance shaping are analyzed and verified through simulations.

关键词： Sequence impedance modular multilevel converter(MMC) grid-forming control(GFC) harmonic transfer function generalized Nyquist criterion

High Frequency Stability Constraints Based MMC Controller Design Using NSGA-III Algorithm

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2023年第2期9卷 623-633页

作者： Ke Ji Weiming Chen Xueguang Wu Hui Pang Jingxuan Hu Shan Liu Fan Cheng Guangfu Tang China Electric Power research institute Beijing 100192China Chen is with state grid Fujian Electric Power research institute Fuzhou 350007China state grid smart grid research institute Beijing 102211China

The occurrence of high frequency resonances(HFRs)has been frequently observed in several MMC-HVDC *** avoid these HFRs,the controller design of an MMC must satisfy two requirements:1)The controller should remain stable while in the high frequency range,and 2)MMC impedance should not possess a negative real part in the high frequency *** far,majority of the related studies on MMC controller design have been unable to address these requirements *** paper first describes the simplified high frequency MMC impedance model developed indigenously by the ***,the driving mechanism of two kinds of HFRs is revealed using the said developed model,including:1)MMC controller instability,and 2)Interaction instability between MMC and AC ***,the mathematical expressions outlining the controller stability constraint and positive damping constraint are ***,NSGA-III based multi-objective optimization algorithm is adopted,to identify the region most suitable for satisfying the proposed stability constraints under the MMC controller *** proposed controller design method is capable of effectively evading the HFRs triggered by the incompatible *** detailed time-domain simulations generated using PSCAD/EMTDC software validate the proposed designed method and endorse the improved results.

关键词： AC cable controller parameter optimization harmonic resonance MMC NSGA-III offshore wind power integration

On modeling of electrical cyber-physical systems considering cyber security

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2016年第5期17卷 465-478页

作者： Yi-nan WANG Zhi-yun LIN Xiao LIANG Wen-yuan XU Qiang YANG Gang-feng YAN College of Electrical Engineering Zhejiang University Hangzhou 310027 China smart grid research institute State Grid Beijing 102209 China

This paper establishes a new framework for modeling electrical cyber-physical systems(ECPSs),integrating both power grids and communication networks. To model the communication network associated with a power transmission grid, we use a mesh network that considers the features of power transmission grids such as high-voltage levels, long-transmission distances, and equal importance of each node. Moreover, bidirectional links including data uploading channels and command downloading channels are assumed to connect every node in the communication network and a corresponding physical node in the transmission grid. Based on this model,the fragility of an ECPS is analyzed under various cyber attacks including denial-of-service(Do S) attacks, replay attacks, and false data injection attacks. Control strategies such as load shedding and relay protection are also verified using this model against these attacks.

关键词： Cyber-physical systems Cyber attacks Cascading failure analysis smart grid

Probabilistic total transfer capability analysis based on static voltage stability region integrated with a modified distributed-level nodal-loading model

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第12期58卷 2072-2084页

作者： WANG Dan ZHOU Yue JIA HongJie WANG ChengShan LU Ning FAN MengHua Key Laboratory of smart grid of Ministry of Education Tianjin University Department of Electrical and Computer Engineering North Carolina State University state grid Energy research institute

In this paper, a new evaluation method of probabilistic TTC based on SVSR calculation is developed through a hierarchical simulation. A smooth technology based on the non-parametric kernel estimator is adapted to obtain the time-dependent probabilistic density function of the feeder-head load data. In order to describe possible operating change directions of the operating point, the original hyper-cone-like(HCL) model is constructed to consider the probabilistic distribution function(PDF) extracted from feeder-head load data to replace the simple Normal Distribution model and the uncertain generator outputs. To realize the fast TTC calculation of the current operating point in random conditions, a sub-hyper-cone-like(SHCL) model in full power injections space is proposed, which is a similarity transformation of the original one.

关键词： voltage stability enhancement demand response demand-side management indirect load control heat pump regulation service

Energy-band alignment of atomic layer deposited(HfO_2)_x(Al_2O_3)_(1-x) gate dielectrics on 4H-SiC

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第3期24卷 408-411页

作者：贾仁需董林鹏钮应喜李诚瞻宋庆文汤晓燕杨霏张玉明 School of Microelectronics Xidian University state grid smart grid research institute Zhuzhou CSR Times Electric Co. Ltd.

We study a series of（HfO2）x（Al2O3）1-x /4H-SiC MOS capacitors. It is shown that the conduction band offset of HfO2 is 0.5 e V and the conduction band offset of Hf AlO is 1.11–1.72 e V. The conduction band offsets of（Hf O2）x（Al2O3）1-x are increased with the increase of the Al composition, and the（HfO2）x（Al2O3）1-x offer acceptable barrier heights（〉 1 e V）for both electrons and holes. With a higher conduction band offset,（Hf O2）x（Al2O3）1-x/4H-SiC MOS capacitors result in a ～ 3 orders of magnitude lower gate leakage current at an effective electric field of 15 MV/cm and roughly the same effective breakdown field of ～ 25 MV/cm compared to HfO2. Considering the tradeoff among the band gap, the band offset, and the dielectric constant, we conclude that the optimum Al2O3 concentration is about 30% for an alternative gate dielectric in 4H-Si C power MOS-based transistors.

关键词： energy-band alignment high k gate dielectrics 4H-SiC MOS capacitor

Graphene superlubricity:A review

在线全文

学校读者我要写书评

暂无评论

Friction 2023年第11期11卷 1953-1973页

作者： Xiangyu GE Zhiyuan CHAI Qiuyu SHI Yanfei LIU Wenzhong WANG School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China state grid smart grid research institute Co. Ltd.Beijing 102209China

Superlubricity has drawn substantial attention worldwide while the energy crisis is challenging human ***,numerous endeavors are bestowed to design materials for superlubricity achievement at multiple *** in graphene-family materials,such as graphene,graphene oxide,and graphene quantum dots,initiated an epoch for atomically thin solid ***,superlubricity achieved with graphene-family materials still needs fundamental understanding for being applied in engineering in the *** this review,the fundamental mechanisms for superlubricity that are achieved with graphene-family materials are outlined in detail,and the problems concerning graphene superlubricity and future progress in superlubricity are *** review concludes the fundamental mechanisms for graphene superlubricity and offers guidance for utilizing graphene-family materials in superlubricity systems.

关键词： superlubricity graphene graphene-family materials two-dimensional(2D)materials friction

Advanced System-Level Model Reduction Method for Multi-Converter DC Power Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第4期10卷 1550-1562页

作者： Lin Zhu Xueshen Zhao Xialin Li Li Guo Bo Zhao Zhanfeng Deng Hao Lu Chengshan Wang the Key Laboratory of smart grid of Ministry of Education Tianjin UniversityTianjin 300072China the research institute of state grid Zhejiang Electric Power Co. Ltd.Hangzhou 310014China the state grid Global Energy Interconnection research institute Beijing 102209China

For dynamic stability analysis and instability mechanism understanding of multi-converter medium voltage DC power systems with droop-based double-loop control,an advanced system-level model reduction method is *** this method,mathematical relationships of control parameters(e.g.,current and voltage control parameters)between the system and its equivalent reduced-order model are ***,open-loop and closed-loop equivalent reduced-order models of current control loop considering dynamic interaction among converters are *** instability mechanism(e.g.,unreasonable current control parameters)of the system can be revealed *** guidance for adjustment of current control parameters can also be ***,considering dynamic interaction of current control among converters,open-loop and closed-loop equivalent reduced-order models of voltage control loop are *** frequency and damping factor of DC bus voltage in a wide oscillation frequency range(e.g.,10–50 Hz)can be evaluated *** importantly,accuracy of advanced system-level model reduction method is not compromised,even for MVDC power systems with inconsistent control parameters and different number of ***,experiments in RT-BOX hardware-in-the-loop experimental platform are conducted to validate the advanced system-level model reduction method.

关键词： Closed-loop reduced-order model instability mechanism open-loop reduced-order model stability analysis system-level model reduction method

Fully Decoupled Branch Energy Balancing Control Method for Modular Multilevel Matrix Converter Based on Sequence Circulating Components

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第1期10卷 235-247页

作者： Zexin Zhao Weijiang Chen Zhichang Yang Guoliang Zhao Bin Han Yunfei Xu Nianwen Xiang Shulai Wang China Electric Power research institute Beijing 100192China state grid Corporation of China Beijing 100031China state grid smart grid research institute Beijing 102209China state Key Laboratory of Advanced Power Transmission Technology Global Energy Interconnection Research InstituteBeijing 102211China Hefei University of Technology Hefei 230009China

The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC ***,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between *** solve this problem,this paper defines sequence circulating components and theoretically analyzes the influence mechanism of different sequence circulating components on branch capacitor voltage.A fully decoupled branch energy balancing control method based on four groups of sequence circulating components is *** method can control capacitor voltages of nine branches in horizontal,vertical and diagonal *** influences of both circulating current and voltage,a cross decoupled control is designed to improve control *** results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing control method are verified in the case of nonuniform parameters and an unbalanced power system.

关键词： Branch energy balancing control decoupled control low-frequency AC transmission modular multilevel matrix converter(M3C) sequence circulating components