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8th IEEE International Conference on Advanced power System Automation and Protection, APAP 2019

作者： Xie, Min Zhang, Wei Liu, Ludeng Jia, Xin Wang, Bin Dong, Xinzhou Dispatching and Controlling Center of Anhui Electric Power Company State Grid Hefei China Tsinghua University Key Lab of Control and Simulation of Power Systems and Generation Equipment China

ISBN: (纸本)9781728117225

The beat frequency characteristic of the recovery voltage of fault phase in the case of single-phase grounding transient fault happening to line with the shunt reactors is analyzed. Besides, the paper analyzes the reason of no beat frequency phenomenon of transient fault happening to line without shunt reactor. The AC power networks with metallic grounding fault and arc grounding fault are analyzed by simulation. The recovery voltage of single-phase grounding fault in AC/DC hybrid power grid is studied by PSCAD. The new problems of the adaptive re-closure in AC-DC hybrid power system are discussed. Then the follow-up ideas to solve several existing problems are also presented. © 2019 IEEE.

关键词： Electric power transmission networks

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Steady-state model of multi-port electric energy router and power flow analysis method of AC/DC hybrid system considering control strategies

Steady-state model of multi-port electric energy router and ...

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作者： Shen, Yu Zhu, Fengju Zhang, Chunpeng Cai, Weiqian Yuan, Liqiang Li, Kai Zhao, Zhengming State Key Lab of Control and Simulation Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

This study proposes a steady-state model of multi-port electric energy router (EER) and a power flow analysis method for AC/DC hybrid system considering control strategies. Firstly, a circuit topology model of EER is put forward, including AC and DC port equivalent parts. Secondly, considering external control characteristics of EER, the control strategies including PQ mode, V/f mode, and droop mode are established, which is suitable for system analysis. Then, using the extended sub-network model, an AC/DC power flow model containing multi-port EER is established. In terms of the power flow algorithm for AC/DC hybrid system, AC/DC network admittance matrix and the extended AC/DC network modification equations are applied to solve the problem. Two examples are designed and show that EER can be used for flexible power regulation and voltage improvement. Besides, power flow analysis method of AC/DC hybrid system is demonstrated to be effective. © 2019 Institution of Engineering and *** right reserved.

关键词： Topology

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Effects of temperature on creepage discharge characteristics in oil-impregnated pressboard insulation under combined AC–DC voltage

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Plasma Science and Technology 2019年第5期21卷 14-22页

作者： Fubao JIN Yuanxiang ZHOU Bin LIANG Zhongliu ZHOU Ling ZHANG Key Laboratory of Plateau Ecology and Agriculture College of Agriculture and Animal HusbandrySchool of Water Resources and Electric PowerQinghai UniversityXining 800016People's Republic of China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084People's Republic of China

Due to the complexity of the valve side winding voltage of the converter transformer, the insulation characteristics of the oil-impregnated pressboard(OIP) of the converter transformer are different from those of the traditional AC transformer. The study on effect of temperature on the creeping discharge characteristics of OIP under combined AC–DC voltage is seriously inadequate. Therefore, this paper investigates the characteristics of OIP creepage discharge under combined AC–DC voltage and discusses the influence of temperature on creepage discharge characteristics under different temperatures from 70 °C to 110 °C. The experimental results show that the partial discharge inception voltage and flashover voltage decrease with increasing temperature. The times of low amplitude discharge(LAD) decrease and amplitude of LAD increases. Simultaneously, the times of high amplitude discharge(HAD) gradually increase at each stage of creepage discharge with higher temperature. The analysis indicates that the charge carriers easily accumulate and quickly migrate directional movement along the electric field ahead of discharging. The residual charge carriers are more easily dissipated after *** ‘hump’ region of LAD moves to the direction of higher discharge magnitude. The interval time between two continuous discharges is shortened obviously. The concentration of HAD accelerates the development of OIP insulation creepage discharge. The temperature had an accelerating effect on the development of discharge in the OIP under applying voltage.

关键词： oil-impregnated pressboard insulation combined AC-DC voltage inception voltage creepage discharge temperature flashover voltage

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Cufe2o4@Ncnts-Functionalized Ceramic Microfiltration Membrane for Antibiotic Oxidation and Fouling control Via Heterogeneous Electro-Fenton Reaction

SSRN

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SSRN 2024年

作者： Zhang, Zixin Huang, Guohe Li, Yongping Yao, Yao Zhang, Peng Chen, Xiujuan Ren, Shaojie Luo, Yifei Zhang, Yuanzheng State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing100875 China State Key Joint Laboratory of Environmental Simulation and Pollution Control China-Canada Center for Energy Environment and Ecology Research UR-BNU School of Environment Beijing Normal University Beijing100875 China Environmental Systems Engineering Program University of Regina ReginaSKS4S 0A2 Canada Institute for Energy Environment and Sustainable Communities University of Regina ReginaS4S 0A2 Canada Department of Civil Engineering The University of Texas at Arlington ArlingtonTX United States Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and Engineering Shandong University Qingdao266237 China College of Environmental Science and Engineering North China Electric Power University Beijing102206 China

Herein, we reported an electrocatalytic ceramic microfiltration membrane functionalized with CuFe2O4 nanoparticles supported by nitrogen-doped carbon nanotubes (NCNTs). The synergistic catalysis between Fe and Cu induced a continuous ·OH generation. The active Fe(II) and Cu(I) sites decomposed the in-situ generated H2O2 into ·OH. The electron transfer from the external circuit and Cu(I) to Fe(III) drove the regeneration of Fe(II). The interfacial electron transfer from CuFe2O4 to NCNTs decreased the electron density of Fe and Cu, thus facilitating the redox cycles of Fe(III)/Fe(II) and Cu(II)/Cu(I). Furthermore, the Fe and Cu sites at the interface of CuFe2O4 and NCNTs displayed a superior ability to non-interface sites in producing ·OH. At near-neutral pH, the electrocatalytic membrane delivered excellent tetracycline removal kinetics (0.0134 min-1) and significantly alleviated the organic fouling occurring on the membrane. These findings shed new light on the development of new-generation membranes with catalytic oxidation capabilities for water treatment. © 2024, The Authors. All rights reserved.

关键词： Antibiotics

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A Novel Method of power Swing Blocking in Impedance Relay 8

A Novel Method of Power Swing Blocking in Impedance Relay

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8th IEEE International Conference on Advanced power System Automation and Protection, APAP 2019

作者： Wang, Hao Kang, Xiaoning Dong, Xinzhou Xi'an Jiaotong University Shaanxi Key Laboratory of Smart Grid Xi'an China Tsinghua University State Key Laboratory of Control and Simulation Power System and Generation Equipment Beijing China

ISBN: (纸本)9781728117225

Distance protection is widely applied in High/Ultra- High Voltage AC transmission system. Impedance relay, the core element of distance protection, may operate incorrectly under power swing, so a power swing blocking unit is needed in distance protection. In this paper, the phase difference between the measurement voltage and compensation voltage under power swing and line fault is analyzed. Based on the analysis, a power swing blocking strategy using the change rate of phase difference between measurement voltage and compensation voltage is proposed. simulation results in PSCAD/EMTDC indicate that the proposed strategy can block the impedance relay reliably under power swing and unblock the impedance relay after detecting the fault under power swing. © 2019 IEEE.

关键词： Electric power system protection

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Space Charge Characteristics of Oil-paper under AC/DC Composite Voltage

Space Charge Characteristics of Oil-paper under AC/DC Compos...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Yuanxiang Zhou Xin Huang Ling Zhang Yunxiao Zhang Zhongliu Zhou Chenyuan Teng Lei Xue Meng Huang The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi China China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Haidian Beijing China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power Universiy Beijing China

ISBN: (纸本)9781728195728;9781728195735

Oil-paper insulation bears AC/DC composite voltage in converter transformers. However, the AC/DC space charge behavior is still not clear, which will result in electric field distortion, material aging and even insulation failure. In this work, the space charge distribution of oil-paper under the AC/DC composite voltage with the AC/DC ratio of 1:1, 1:3, 1:5, and 1:7, is studied by pulse electroacoustic (PEA) method, respectively. It was found that as DC component increases, the accumulated charge near the electrode decreases, while the interior charge increases. It suggests that DC stress mainly influences the amount and the depth of space charge accumulation. AC component has a relatively significant impact on the injection and extraction behavior of space charge near the electrode. Furthermore, AC/DC composite voltage enhances the migration of space charge compared with that under DC voltage. This research contributes to the further understanding of the space charge characteristics of oil-paper under AC/DC composite voltage, which will benefit the safe and stable operation of converter transformers.

关键词： Electrodes Conferences Space charge Oil insulation Aging Distortion Dielectrics

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Improve the Conversion Rate and Selectivity of Aromatic Monomers in Lignin Photocatalytic Conversion Reaction Via Phase Junction Cadmium Sulphide Nanoparticles and External Hydrogen Supplier

SSRN

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SSRN 2023年

作者： Yue, Zongyang Shao, Shibo Yu, Jialin Lu, Guanchu Wei, Wenjing Huang, Yi Zhang, Kai Wang, Ke Fan, Xianfeng Institute for Materials and Processes School of Engineering The University of Edinburgh EdinburghEH9 3BF United Kingdom Petrochemical Research Institute PetroChina Company Limited Beijing102206 China Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Innovation Academy for Green Manufacture Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China Longzihu New Energy Laboratory Zhengzhou Institute of Emerging Industrial Technology Henan University Zhengzhou450000 China Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation North China Electric Power University Beijing102206 China

Photocatalysis has the potential for lignin valorisation to generate functionalised aromatic monomers, but its large-scale application has been limited by the slow conversion rate and the low selectivity to desirable products. In this work, record-high lignin model compound Cβ-O bonds cleavage rate and excellent selectivity to aromatic monomers has been achieved over the development of new hexagonal-cubic phase junction CdS nanoparticles, enhanced external hydrogen donor supply and hydrogen transfer, and improved separation efficiency of photo-excited electron-hole pairs. Water is employed as external hydrogen supplier, resulting in significant increase in the conversion rate of 2-Phenoxy-1-phenylethanol (PP-ol) as lignin model from 21.8% to 100% and the selectivity of aromatic monomers from ~45% to ~94% under 1h of visible light irradiation. 2-phenoxyacetophenone (PP-one) as by-product from PP-ol conversion can be further completely cleaved to aromatic monomers with assistance of TEA and reaction time is reduced from 2-12 hrs to10 min under visible-light irradiation. © 2023, The Authors. All rights reserved.

关键词： Lignin

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Fast Monte Carlo simulation of Dynamic power systems under Continuous Random Disturbances

arXiv

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arXiv 2020年

作者： Qiu, Yiwei Lin, Jin Chen, Xiaoshuang Liu, Feng Song, Yonghua State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China Department of Electrical and Computer Engineering University of Macau 999078 China

—Continuous-time random disturbances from the renewable generation pose a significant impact on power system dynamic behavior. In evaluating this impact, the disturbances must be considered as continuous-time random processes instead of random variables that do not vary with time to ensure accuracy. Monte Carlo simulation (MCs) is a nonintrusive method to evaluate such impact that can be performed on commercial power system simulation software and is easy for power utilities to use, but is computationally cumbersome. Fast samplings methods such as Latin hypercube sampling (LHS) have been introduced to speed up sampling random variables, but yet cannot be applied to sample continuous disturbances. To overcome this limitation, this paper proposes a fast MCs method that enables the LHS to speed up sampling continuous disturbances, which is based on the Itô process model of the disturbances and the approximation of the Itô process by functions of independent normal random variables. A case study of the IEEE 39-Bus System shows that the proposed method is 47.6 and 6.7 times faster to converge compared to the traditional MCs in evaluating the expectation and variance of the system dynamic response. Copyright © 2020, The Authors. All rights reserved.

关键词： Monte Carlo methods

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Deep learning-aided model predictive control of wind farms for AGC considering the dynamic wake effect

arXiv

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arXiv 2020年

作者： Chen, Kaixuan Lin, Jin Qiu, Yiwei Liu, Feng Song, Yonghua State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100087 China Department of Electrical and Computer Engineering University of Macau 999078 China

To provide automatic generation control (AGC) service, wind farms (WFs) are required to control their operation dynamically to track the time-varying power reference. Wake effects impose significant aerodynamic interactions among turbines, which remarkably influence the WF dynamic power production. The nonlinear and high-dimensional nature of dynamic wake model, however, brings extremely high computation complexity and obscure the design of WF controllers. This paper overcomes the control difficulty brought by the dynamic wake model by proposing a novel control-oriented reduced order WF model and a deep-learning-aided model predictive control (MPC) method. Leveraging recent advances in computational fluid dynamics (CFD) to provide high-fidelity data that simulates WF dynamic wake flows, two novel deep neural network (DNN) architectures are specially designed to learn a dynamic WF reduced-order model (ROM) that can capture the dominant flow dynamics. Then, a novel MPC framework is constructed that explicitly incorporates the obtained WF ROM to coordinate different turbines while considering dynamic wake interactions. The proposed WF ROM and the control method are evaluated in a widely-accepted high-dimensional dynamic WF simulator whose accuracy has been validated by realistic measurement data. A 9-turbine WF case and a larger 25-turbine WF case are studied. By reducing WF model states by many orders of magnitude, the computational burden of the control method is reduced greatly. Besides, through the proposed method, the range of AGC signals that can be tracked by the WF in the dynamic operation is extended compared with the existing greedy controller. Copyright © 2020, The Authors. All rights reserved.

关键词： Model predictive control

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Research on the Substitution Ability of Battery Energy Storage system for Thermal power Units in Frequency Regulation

Research on the Substitution Ability of Battery Energy Stora...

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Sustainable power and Energy Conference (iSPEC)

作者： Huan Zhu Kaifeng Wang Ying Qiao Lirong Xie Guojing Liu State Grid Jiangsu Electric Power Company Economic Research Institute Nanjing China Xinjiang University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments of Electrical Engineering (Tsinghua University) Urumqi and Beijing China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments of Electrical Engineering Tsinghua University Beijing China Xinjiang University Urumqi China

ISBN: (数字)9781728191645

ISBN: (纸本)9781728191652

When penetration levels of renewable energy of power system are increased, the proportion of thermal power units will gradually decrease. This will cause the frequency regulation capacity of the power system to gradually decline. To this end, battery energy storage systems are widely used to frequency regulation in the power system. However, the frequency regulation ability of battery energy storage system to substitute thermal power units has not yet been quantified. In this paper, it introduces two frequency regulation method models. In the proposed models, the influence of different energy storage participation degrees on the effect of frequency regulation is analyzed, and a power and energy indicators system for quantifying energy storage substitution ability is proposed based on the advantages of frequency regulation with energy storage. The simulation results indicate that the ability of energy storage to substitute thermal power units is about 20-35 in terms of rapid energy supply when the installed capacity is same.

关键词： Renewable energy sources simulation power system stability Stability analysis Batteries Frequency control Thermal stability

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