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2017 International Conference on Mechanical and Mechatronics Engineering(ICMME2017)

作者： Gun YANG Zhan-qing YU Hong-jun ZHEN Chao SU Shui-ming CHEN Rong ZENG Jin-liang HE State Key Lab.of Control and Simulation of Power Systems and Generation Equipment Department of Electrical EngineeringTsinghua University Qingyuan Power Supply Bureau of Guangdong Grid Company

The fault of transmission line is mostly caused by lightning,and a ground lightning stroke process is often accompanied by multiple *** duration of ground lightning stroke are also *** this paper,a method for evaluating the reclosing time of reclosure based on lightning parameters is *** addition,this paper also gives an expression for the cumulative rate of the duration of ground lightning stroke,and an expression for probability distribution of the amplitude of lightning current in Guangdong *** also proposed a method for calculating the probability of tripping of *** this calculating method,the average probability of tripping of reclosure is less than 1/10000 during a ground lightning stroke process,when the reclosing time t0 is greater than 1.012 s.

关键词： Ground lightning stroke Lightning parameters Reclosing time of reclosure Probability of tripping of reclosure

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The Actual Operation of Transmission Line and Evaluation of the Reclosing Time of Reclosure

The Actual Operation of Transmission Line and Evaluation of ...

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2017 International Conference on Mechanical and Mechatronics Engineering(ICMME2017)

作者： Rui-ming OU Gun YANG Zhan-qing YU Jin-bo WU Shui-ming CHEN Hong-jun ZHEN Qingyuan Power Supply Bureau of Guangdong Grid Company State Key Lab.of Control and Simulation of Power Systems and Generation Equipment Department of Electrical EngineeringTsinghua University

In this paper,the actual trip of typical transmission line is *** includes the trip frequency of transmission lines and the tripping frequency caused by lightning,seasonal distribution characteristics of transmission line trip,and the success rate of reclosing on the transmission *** this paper,the probability of the occurrence of the trip again is evaluated based on the duration of ground lightning *** the increase of the time of reclosure,the probability of the occurrence of the trip will *** this calculating method,the average probability of tripping of reclosure decreased significantly during a ground lightning stroke process,when the reclosing time t0 is 1 s.

关键词： Trip of transmission line Trip caused by lightning Reclosing time of reclosure Probability of tripping of reclosure

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Analysis of Adaptive Re-closure in AC-DC Hybrid power System

Analysis of Adaptive Re-closure in AC-DC Hybrid Power System

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International Conference on Advanced power System Automation and Protection (APAP)

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

ISBN: (数字)9781728117225

ISBN: (纸本)9781728117232

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.

关键词： Circuit faults Inductors Shunts (electrical) Transient analysis Integrated circuit modeling Grounding Capacitance

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A voltage control strategy for preventing cascading trips of large-scale wind power in centralized area

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Dianli Xitong Zidonghua/Automation of Electric power systems 2014年第11期38卷 7-12页

作者： Ding, Tao Guo, Qinglai Sun, Hongbin Xu, Fengda Xu, Xiaofei Jia, Lin Department of Electrical Engineering Tsinghua University Beijing China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China North China Power Grid Co. Ltd. Beijing China

Cascading wind farm trips have brought new challenge to the wind power integration. Traditional reactive power optimization can achieve a desirable control result, but voltage security violation usually happens after N-1 contingency because of the redistribution of power flow and slow response by the reactive power compensator. Therefore, a reactive power optimization model is set up with security constraints, aiming to maintain the voltage within the security region under both normal condition and N-1 contingency. Besides, Benders decomposition method is employed to solve the complex model, dividing into one master and some slave problems. Iterative method is used between master and slave problems to obtain the optimal solution. Practical power grid with nine wind farms is tested, and the comparison of security constrained optimal power flow (SCOPF) and traditional optimal power plow shows that the SCOPF has better effect, which can maintain the voltage security under both normal condition and N-1 contingency. So it is an effective method to prevent cascading faults of multiple wind farms integrated into power grid. Finally, the relationship of maximum wind power integration, wind farm capacity and reactive power capacity of wind units is fully studied to provide certain help for the operation of wind farm. ©2014 state Grid Electric power Research Institute Press

关键词： Wind farm

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ANALYSIS OF THE MULTI-MODE OSCILLATIONS OF OFFSHORE WIND FARMS 18

ANALYSIS OF THE MULTI-MODE OSCILLATIONS OF OFFSHORE WIND FAR...

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

作者： Fan, Yupeng Dong, Wenkai Li, Peng Qin, Yi Jiang, Haojie Xie, Xiaorong Datang Guoxin Binhai Offshore Wind Power Generation Co. Ltd Jiangsu Province Yancheng224000 China State Key lab of Control and Simulation of Power Systems and Generation Equipment Dept. of Electric Engineering Tsinghua University Beijing100084 China China Datang Corporation Science and Technology General Research Institute Ltd Beijing100040 China

ISBN: (数字)9781839537615

ISBN: (纸本)9781839537615

Multi-mode oscillation (MMO) is more prone to happen in the offshore wind farm (OWF) than the onshore, which seriously impacts the safe operation of the system. In this paper, the mechanism for the MMO of the OWF is analytically studied. First, the impedance model (IM) of a grid-connected OWF is derived with the AC submarine cable modelled as a distributed parameter circuit (DPC). Second, since the DPC of N n sections can be approximately seen as composed of N identical capacitances in daisy-chain connection, based on the consistent control theory for homogeneous systems, the IM of the DPC is decoupled into N subsystems, each of which is composed of a x circuit. The IM of the DPC is the weighted sum of the IMs of the N subsystems. As each x circuit has one tip (jump between ±90°) in the amplitude(phase)-frequency characteristics (APFC), the IM of the cable will have N tips (jumps) in the APFC and is much more prone to intersect with the IM of the OWF. Thus, resonance is more likely to happen at multiple frequency points. Finally, effectiveness of the methods proposed and conclusions drawn is validated via study cases. © ACDC 2022. All rights reserved.

关键词： Offshore wind farms

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Accurate flux observer based on distributed multi-processor in MV adjustable speed drive system

Accurate flux observer based on distributed multi-processor ...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Liu Shu Liu Jianzheng Zhao Zhengming Yuan Liqiang Bai Hua Zhang Haitao Department of Electrical Engineering and Applied Electronic Technology State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

This paper presents an accurate flux observer used in distributed multi-processor (DMP) adjustable speed drive systems. The stator flux linkage is estimated with a full-order observer, while the rotor speed is identified by using Lyapunov theorem. In order to improve the system performance in a wide speed range, the stator resistance is estimated simultaneously. In this paper, the structure of the DMP system, the principle of the full-order observer and the method for identifying the rotor speed and state resistance are all described in details. Relevant simulation results based on MATLAB/SIMULINK are given to prove the performance of the method. Experiments of a real system also verify the feasibility of this scheme

关键词： Variable speed drives Stators Observers control systems Mathematical model Couplings Torque control Optimal control Sampling methods Pulse width modulation

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A novel fiber-CAN-based real time communication system for MV-ASD systems

A novel fiber-CAN-based real time communication system for M...

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International Conference on Electrical Machines and systems (ICEMS)

作者： Jue Qian Zhengming Zhao Haitao Zhang Hua Bai Liqiang Yuan Department of Electrical Engineering and Applied Electronic Technology State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

The voltage increment in MV-ASD systems deteriorates the electromagnetic environment, therefore the communication system is facing a formidable challenge in the attempt to achieve the numerous real-time interactivities among those subsystems under such electromagnetic circumstance. This paper focuses on the real-time communication system for the MV-ASD systems, in which electromagnetic compatibility (EMC), real-time performance and system reliability are considered simultaneously. A novel fiber-CAN network is designed and implemented, which remarkably increases EMC compared to the conventional ones. The CAN system that serves in the multiprocessor control system for the MV-ASD system with the rated power of 1 MW is implemented. From the experiment results in the MV-ASD system with a 690 kW motor, it can be verified that the requests of timing performance and the reliability for the communication system are well accomplished

关键词： Optical fiber communication Real time systems control systems Communication system control Circuits Torque control Electromagnetic compatibility Pulse width modulation inverters Optical fiber devices power system simulation

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Fault diagnosis for multi-energy flows of energy internet: Framework and prospects

Fault diagnosis for multi-energy flows of energy internet: F...

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2017 IEEE Conference on Energy Internet and Energy System Integration, EI2 2017

作者： Wang, Tao Wang, Jun Fan, Zhennan Wei, Xiaoguang Zang, Tianlei Pérez-Jiménez, Mario J. Huang, Tao School of Electrical Engineering and Electronic Information Sichuan Province Key Laboratory of Power Electronics Energy-saving Technologies and Equipment Key Laboratory of Fluid and Power Machinery Ministry of Education Xihua University Chengdu China School of Electrical Engineering Southwest Jiaotong University Chengdu China State Key Laboratory of Security Control and Simulation of Power Systems and Large Scale Generation Department of Electrical Engineering Tsinghua University Beijing China Research Groupon Natural Computing Department of Computer Science and Artificial Intelligence University of Sevilla Sevilla Spain Department of Energy Politecnico di Torino Torino Italy

ISBN: (纸本)9781538614273

Energy Internet (EI) is an inevitable development trend of energy systems under the background of technology development, environmental pressure and energy transition. Multi-energy flow coupling is one of the key characteristics of the EI, which enhances the interoperability of different types of energy flows while consequently increases the probability of cascading failures. Therefore it is of great significance to study the multi-energy flow fault diagnosis of the EI to ensure its safe and stable operation as well as the continuous energy supply. This paper introduces the concept of multi-energy flow cascading fault of the EI for the first time. The energy internet framework for multi-energy flow cascading fault diagnosis is firstly proposed, and then characteristics of various energy networks in the EI are analyzed from the perspective of fault diagnosis. Finally, future research prospects are discussed. © 2017 IEEE.

关键词： Failure analysis

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Nickel Phase Invades Ysz Electrolyte Through Ysz/Ysz Grain Boundary During Long-Term Operation of Sofc

SSRN

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SSRN 2023年

作者： Liu, Jiawei Wang, Yige Lyu, Zewei Wang, Chenpeng Ma, Yue Ye, Hao Liu, Yinglong Liu, Yingli Xu, Xiaoru Chen, Zhicong Han, Minfang Liang, Bo School of Materials and Energy Guangdong University of Technology Guangzhou510006 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Energy and Power Engineering Tsinghua University Beijing100084 China

A solid oxide fuel cell after long-term operation more than 5000 hours, nickel (Ni) phase is observed at YSZ/YSZ grain boundaries (GBs) within electrolyte. By using a humidified hydrogen, the single cell is electrochemically operated at 720℃ under 0.10 A·cm-2. The thickness of anode/electrolyte interface is thinned to less than 100 nm by a dual beam focused ion beam-scanning electron microscope (FIB-SEM). As-thinned electrolyte is analyzed by using High-Resolution Transmission Electron Microscopy (HR-TEM). The discrete nanostructures ranging from 50nm to 5nm are observed to have developed exclusively along the YSZ/YSZ grain boundaries. It is noted that the nickel phase is found in YSZ GBs of the electrolyte. FFT patterns shows that the invasion phase of nickel is FCC-Ni. A suggested mechanism has been put forth to explain the invasion of Ni phases into the electrolyte through YSZ/YSZ grain boundary. This mechanism takes into consideration the evolution of nanostructures, as well as the diffusion and nucleation of Ni, which involves the formation of Ni-OH species. © 2023, The Authors. All rights reserved.

关键词： Nanostructures

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Construction of Vehicle Driving Conditions Based on Rain flow Counting Theory 6

Construction of Vehicle Driving Conditions Based on Rain flo...

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6th CAA International Conference on Vehicular control and Intelligence, CVCI 2022

作者： Wang, Yunyi Lin, Jiamei Wang, Chao Guo, Jinyan Liu, Sihan Song, Xincheng School of Mechanical and Aerospace Engineering Key Laboratory of Cnc Equipment Reliability Jilin Changchun China Jilin University State Key Laboratory of Automotive Simulation and Control Jilin Changchun China Changchun Power Supply Company Construction Department Jilin Changchun China Engineering Training Center Jilin University Jilin Changchun China School of Mechanical and Aerospace Engineering Jilin Changchun China

ISBN: (数字)9781665453745

ISBN: (纸本)9781665453745

Vehicle driving conditions are used to describe the driving characteristics of a vehicle in a specific traffic environment. which can provide an important reference for vehicle fuel consumption and pollutant control. This paper presents a description of automotive vehicle working conditions based on rain flow counting theory. By using principal component analysis, the main characteristic parameters are obtained to represent the total sample, and the driving speed mapping method based on the rain flow counting theory is used to construct the vehicle driving condition curve that conforms to the urban characteristics. © 2022 IEEE.

关键词： Principal component analysis

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