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2011 International Conference on Advanced power System Automation and Protection, APAP 2011

作者： Liu, Kun Dong, Xinzhou Wang, Bin Shi, Shenxing State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781424496198

This paper analyzes the general process of power flow transferring and divides it into four parts: 1) the process of first phase selection after fault occurs;2) the process of selective action at the first time;3) the process of second phase selection and status confirmation;4) the process after status confirmation. It points out that the issue of asymmetrical flow transferring is a critical process which must be put emphasis on. Then it proposes a method to identify this process, and discuss different solution methods. © 2011 IEEE.

关键词： Electric load flow

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Research on operation and control of low voltage photovoltaic-energy storage DC building system 18

Research on operation and control of low voltage photovoltai...

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18th International Conference on AC and DC power Transmission, ACDC 2022

作者： Guo, Peiqian Yuan, Zhichang Han, Xuejiao Wu, Aijun Wang, Yuxuan Jiang, Zhilin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China Energy Internet Research Institute Tsinghua University Beijing China

ISBN: (数字)9781839537615

ISBN: (纸本)9781839537615

The spread of the power electronics, both for control and power applications, in the realization of apparatuses the DC transformation in building distribution and utilization system. Currently, the research and discussion of the operation scheme and control strategy for low voltage photovoltaic-energy storage DC building system, LVPESDCBS, are relatively less. Focusing on these, in-depth research and analysis for control and operation scheme are conducted, and the related application possibility for different types LVPESDCBSs is discussed in this paper. At the start, the existing operational control strategies for the DC system are summarized. Following this, the centralized operational control scheme, which applies to the existing buildings that need to be renovated to DC type, and the decentralized operational control scheme for newly built DC buildings are studied respectively. Taking these conclusions into consideration, a ±375V LVPESDCBS digital model with various types of AC/DC power electronic devices is established in PSCAD/EMTDC. The proposed control strategy and operational scheme are verified through normal operation and single-pole operation of this LVPESDCBS. Finally, extended marketability requirement discussions of future DC building based on three perspectives: data drives, converter devices, and the application of DC technology are presented. © ACDC 2022. All rights reserved.

关键词： Digital storage

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Estimating the electromechanical oscillation characteristics of power system based on measured ambient data utilizing stochastic subspace method

Estimating the electromechanical oscillation characteristics...

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2011 IEEE PES General Meeting: The Electrification of Transportation and the Grid of the Future

作者： Jingmin, Ni Chen, Shen Feng, Liu State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781457710018

Estimating low-frequency oscillation modes and the corresponding mode shapes based on ambient data from WAMS measurements has a promising prospect of application in power system analysis and control. The present approaches estimate the modes and mode shapes respectively, which greatly reduce the computational efficiency. Besides, there is no good solution for the problem of discriminating real modes from the spurious ones caused by numerical error. A method based on stochastic subspace method was proposed in this paper. By choosing the angle measurements of all buses as input signals for the method, the modes and simultaneously the corresponding mode shapes of any bus can be estimated conveniently. By introducing the idea of reference channels, the computation complexity was substantially reduced without decreasing the accuracy. Stabilization diagrams technique was introduced to discriminate the real modes from the spurious ones. The test case based on the IEEE-118 system indicated that the method proposed is satisfying in respect of both computational efficiency and accuracy of results. © 2011 IEEE.

关键词： Computational efficiency

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A novel fault locator for power distribution system with neutral non-effectively grounded

A novel fault locator for power distribution system with neu...

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2011 International Conference on Advanced power System Automation and Protection, APAP 2011

作者： Shi, Shenxing Dong, Xinzhou State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781424496198

Fault locator for power distribution system with neutral non-effectively grounded should locate phase-to-phase fault and single-phase-to-ground fault respectively. For phase-to-phase fault, the point can be located by power-frequency impedance. However, for single-phase-to-ground fault with limited power-frequency current not more than load current, a novel fault location technology should be developed. The paper will present a practical single-phase-to-ground fault location based on fault generated traveling waves acquired from one phase current transducer and zero sequence current transducer at first. Then implementation of the novel fault locator is proposed including hardware design and software flowchart. At last field tests will be made to verify the feasibility of the fault locator. © 2011 IEEE.

关键词： Transducers

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Charge Evolution and Dielectric Property of Three-phase Polypropylene Composites With Enhanced Mechanical Performance

Charge Evolution and Dielectric Property of Three-phase Poly...

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中国物理学会第二十二届全国静电学术年会

作者： Ling Zhang Zhaowei Peng Yuanxiang Zhou Zekai Lu Yonggang Guan Zixia Cheng State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department School of Electrical Engineering Zhengzhou UniversityZhengzhou 450001China

High voltage DC(HVDC)power cable technology has the advantages of large transmission capacity,low loss,negligible electromagnetic environmental effect,and trackless corridor,etc.,which make it capable to solve the significant problem of power transmission channels during the fast development of electric ***,it also contributes to eco-friendly,resource-saving,safe,and reliable goal of power transmission *** to common crosslinked polyethylene materials,isotactic polypropylene(iPP)has the advantages of non-crosslinking,high-temperature-resistant,recyclable,low production cost,and free maintenance work,and has been a hot spot in the research field of high performance HVDC cable insulating ***,iPP is a thermoplastic limited by its impact strength,especially at low temperatures,because of its high degree of crystallinity and high glass transition *** of the common methods used to increase the impact strength is the addition of low-molecular elastomer materials or nucleating agents(NAs)into the iPP matrix,which is blended with the polymer in the molten *** previous investigations with the binary blending system have demonstrated that improved impact resistance usually was accompanied by decreasing the stiffness or deteriorating its original electrical properties in some *** order to achieve an optimum balance of macroscopic properties,adding several components is often necessary in polymer *** aim of this work is to investigate the synergistic effects on mechanical and electrical properties between NAs and different elastomers in iPP *** have shown that increasing the β-crystal content can improve its electrical property and elastomer can strengthen its mechanical performance.,Thus,three-phase iPP blends(iPP-β-x,x refers to the elastomer)were prepared with the incorporation of arylamide derivative β-NAs(TMB-5,0.2 wt%)and different elastomers(15 wt%)including styrene-bethylene butylene-b-styr

关键词： isotactic polypropylene β nucleating agent elastomer impact strength space charge

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Analyses on frequency transmission characteristic of traveling wave in distribution power system

Analyses on frequency transmission characteristic of traveli...

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2011 International Conference on Advanced power System Automation and Protection, APAP 2011

作者： Wang, Jun Shi, Shenxing Dong, Xinzhou Wang, Bin State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781424496198

Under the skin effect caused by the alternating electromagnetic field, the transmission line parameters changes with frequency, and different line resistivity, surge impedance, wave speed are presented in one line under the different frequency bands of signal. This phenomenon is usually called Frequency transmission characteristic, which is mainly discussed in this paper. This paper first studied the line resistivity, wave speed and surge impedance of zero-mode component and line-mode component in different frequency bands. Then, the line structure and its effection on Frequency transmission characteristic are presented. Last, the frequency transmission characteristic on a certain line fault is discussed based on a typical distribution system model. The research in this paper is meaningful for future study on the fault feeder selection and fault location technology based on traveling wave in the distribution system. © 2011 IEEE.

关键词： Wavelet transforms

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Transient Behaviors of Space Charge in Low-density Polyethylene Films at Prebreakdown Under Temperature Fields

Transient Behaviors of Space Charge in Low-density Polyethyl...

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中国物理学会第二十二届全国静电学术年会

作者： Ling Zhang Zekai Lu Yuanxiang Zhou Zhaowei Peng Zixia Cheng Yonggang Guan State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department School of Electrical Engineering Zhengzhou UniversityZhengzhou 450001China

Currently,insulation performance of high voltage DC(HVDC)power cables is still of critical significance challenge in both engineering application and fundamental *** example,HVDC cable insulation suffers breakdown under the conditions of cold start and load cycling tests,and the presence of space charge at high temperatures causes electric field distortion within the ***,the operating temperature of HVDC cables could only reach 70℃at *** work intends to carry out research on the effect of temperature on space charge characteristics of low-density polyethylene(LDPE)films at prebreakdown under a linearly ramping voltage,which is of great significance for further understanding and improving the operating temperature and breakdown strength of HVDC ***-free LDPE film with a thickness of 100 μm was purchased from GoodFellow *** improved space charge measurement system was developed with a high-speed measurement interval of 1 ms,a high voltage pulse of 120 V,and a pulse width of 5 ns.A linearly ramping voltage of 0.5 kV/s was selected and cut off after breakdown *** and steady behaviors of space charge was comprehensively sudied under a linearly ramping voltage of 500 V/s at 30℃and 70℃,*** results show that negative charge was rapidly injected and accumulated near the anode at a relatively low electric field at 70℃.As the applied electric field gradually increased,the anode appeared a significant positive charge *** phenomenon occurred when charge packets were injected to a certain distance of~30 μ*** the contrast,there was only negative charge injection and accumulation in the bulk of LDPE films at 30℃,and breakdown was not observed even when the voltage rose to-30 *** was found that the anode had a positive space charge packet injection at 30℃and slowly migrated to the cathode,and the entire transit process took tens of *** the internal electric field distribution,the ma

关键词： LDPE prebreakdown transient space charge internal field distortion carrier mobility

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Principle and Model for Regional Allocation of Carbon Emission from Electricity Sector

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Electricity 2012年第4期23卷 52-53页

作者： Li Baowei Hu Zechun Song Yonghua Wang Guanghui State Key Lab of Control and Simulation of Power Systems and Generation Equipment Dept. of Electrical Engineering Tsinghua University

The paper “Principle and Model for Regional Allocation of Carbon Emission from Electricity Sector” is focused on the hot issue of carbon allocation problem,while the research scope is restricted to electricity *** authors propose a fair allocation principle considering the social contribution and environmental cost of electricity *** to the allocation principle,a novel model and concept of carbon flow tracing is presented to satisfy the requirements based on electricity flow tracing methodology,which traces the sources of regional electricity imports to determine the carbon allocation reasonably.

关键词：分配原则电力行业碳排放跟踪方法分配问题电力部门电力供应碳分配

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Comparison of two basic structures in magnetically-coupled resonant wireless power transfer

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Diangong Jishu Xuebao/Transactions of China Electrotechnical Society 2013年第SUPPL.2期28卷 18-22页

作者： Zhang, Yiming Zhao, Zhengming Yuan, Liqiang Lu, Ting State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing 100084 China

Wireless power transfer (WPT) has been a research focus in recent decades. Based on magnetically-coupled resonant WPT (MCR-WPT), this paper made a comparison of two basic structures in MCR-WPT: the two-coil structure and the four-coil structure. Their equivalent circuits were built. To illuminate the difference between these two structures, the input impedance, the transfer efficiency, and the load matching were studied and tested by experimental results. The conclusion is drawn that without reducing the transfer efficiency, the addition of the source coil and the load coil in the four-coil structure makes it easier to match the source and the load than the two-coil structure.

关键词： Magnetic resonance

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Design Optimization of Ferrite Rings for VFTO Mitigation

Design Optimization of Ferrite Rings for VFTO Mitigation

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作者： He, Jiaxi Guan, Yonggang Liu, Weidong Chen, Weijiang Li, Zhibing The Department of Electrical Engineering State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing100084 China State Grid Corporation of China Beijing100031 China China Electric Power Research Institute Beijing100192 China

very-fast transient overvoltage (VFTO)-related problems are raising growing concerns in China with the development of ultra-high voltage. The practice of fitting ferrite rings on gas-insulated switchgear busbars for VFTO mitigation has long been proposed but few investigations on its design optimization were conducted. Based on theoretical analysis of the simplified model, the optimal damping condition of ferrite rings is proposed, which is conducive to the type selection. The number of rings to be employed to ensure visible suppressing effects is given through simulations and the influence of the saturation is discussed. Impact on the power frequency is analyzed to be negligible. Finally, comparisons are made between the theoretical conclusions and existing experiment results, which approve the optimal damping condition and agree with the number of rings to be employed. © 2014 IEEE.

关键词： Damping

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