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Synergism analysis of an urban metabolic system: Model development and a case study for Beijing, China

Ecological Modelling 2014年 272卷 188-197页

作者： Yan Zhang Hong Liu Brian D. Fath State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Beijing Normal University Xinjiekouwai Street No. 19 Beijing 100875 China Biology Department Towson University Towson MD 21252 USA Advanced Systems Analysis Program International Institute for Applied System Analysis Laxenburg Austria

The efficiency of urban metabolic processes depends on the degree of mutualism of these processes throughout the metabolic system and on the value gained by each compartment within the system. This can be assessed by means of ecological network-based synergism analysis. In this paper, we used material-flow accounting methods to account for the exchanges of resources and wastes among the compartments of an urban system. Using a seven-compartment urban metabolic network model of Beijing, China, as a case study, we examined the degree of synergism of the compartments, determined the nature of the resulting ecological relationships, and determined the flow of utility to each compartment within the system. The results revealed which types of ecological relationship contributed most to the system (here, exploitation) and identified the key compartments that decreased the system's degree of synergism. The results provide theoretical and empirical support for the development of policies designed to promote healthy development of Beijing's urban metabolic system.

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Design of multichannel real-time data transceiver for wireless meter reading network

Design of multichannel real-time data transceiver for wirele...

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World Congress on Intelligent control and Automation (WCICA)

作者： Ting Yuan Shijie Cui Zhijun Shang Peng Zeng Haibin Yu Chuanzhi Zang Qiang Gao Ping Li Ming Guan Jing Zhang Panjin power supply company State Grid Liaoning electric power company limited Panjin China Shenyang Institute of Automation Chinese Academy of Sciences Shenyang China Key Laboratory of Networked Control Systems Chinese Academy of Sciences Shenyang China Electric power research institute State Grid Liaoning electric power company limited Shenyang China

Debugging and protocol conformance testing of power meter reading system which is based on wireless sensor network is complex, aiming at this problem, we develop a powerful, flexible use, convenient carrying multichannel real-time data monitoring and transmitting device in this paper. The hardware realization and working principle of multichannel synchronous data transceiver are introduced in detail. On this basis, its hardware scheme and software flow for wireless meter reading network are designed. The tests show that, the device is with good real-timeand high stability which is a good debugging and testing device for wireless meter reading network.

关键词： Field programmable gate arrays Wireless sensor networks Wireless communication Meter reading Radio frequency Synchronization Debugging

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Air-gap magnetic field distribution and inductance characteristics in a long primary sectional powered variable pole pitch linear induction motor

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Qinghua Daxue Xuebao/Journal of Tsinghua University 2014年第9期54卷 1161-1165and1172页

作者： Mu, Shujun Chai, Jianyun Sun, Xudong Wang, Shanming State Key Lab. of Security Control and Simulation of Power Systems and Large Scale Generation Equipments Department of Electrical Engineering Tsinghua University Beijing100084 China

This study investigated the air-gap magnetic field distribution and inductance characteristics of a long primary sectional powered variable pole pitch linear induction motor (VPPLIM). A one-dimensional analytical model and a 2-D finite element model were used to analyze the air-gap magnetic field distribution in the VPPLIM with harmonic fields for uniformly accelerating the mover with a typical AC supply. The air-gap magnetic field distribution was used to develop analytical expressions for the self-and mutual-inductances of the motor and their characteristics. The analytical expressions are verified by the finite element simulations. ©, 2014, Press of Tsinghua University. All right reserved.

关键词： Inductance

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Functionality identification for the testing systems with large-scale highly-concentrated wind power integration by long-distance transmission lines

Functionality identification for the testing systems with la...

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IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT Europe)

作者： Jiabing Hu Yunhe Hou Feng Liu Yongning Chi Shuanglei Feng Haiyan Tang Guobing Song Xiaoming Yuan State Key Lab of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China Department of Electrical and Electronic Engineerig The University of Hong Kong Hong Kong China State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China China Electric Power Research Institute Beijinz China Department of Electrical Engineering Xi’ an Jiaotong University Xi'an China

ISBN: (纸本)9781479977215

Large-scale, highly-concentrated wind power integrated into grids through long transmission lines will bring significant challenges to power system operation during steady-state and dynamic processes. Tremendous research has been conducted in this critical area. However, few, if any available testing systems have been established to meet the requirements of the research on different time-scales. The objective of this paper is to identify the functionality requirements of the testing systems for the comprehensive studies, which covers different time-scale problems of power systems. For this purpose, the realistic Gansu power grids in China and wind farms in Jiuquan area are selected. As a typical power grid with large-scale highly-concentrated wind power integration by long-distance transmissions, the characteristics of the selected wind farms and power grid are discussed first. Two simplified systems are constructed associated with the major characteristics. The critical functionality requirements of the testing systems for different research purposes, i.e., system planning, operation, control, and protection, are identified. As the first step, this paper scopes the key requirements and, ultimately, a complete testing system is expected.

关键词： Wind power generation power system stability Stability analysis Testing Wind farms Frequency control power grids

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采用Fisher判别法对GIS中局部放电类型的识别(英文)

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高电压技术 2013年第4期39卷 805-812页

作者： DING Dengwei GAO Wensheng LIU Weidong State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical EngineeringTsinghua University

To monitor the condition of online power apparatus accurately and provide appropriate guidance on their maintenance,a fundamental ultra-high frequency(UHF) database of partial discharges corresponding to different types of defects is presented for the observation of insulation state of gas insulated switchgear(GIS).In order to imitate the defects in a GIS online,five types of typical partial discharge(PD) sources(*** metal,protrusion,bouncing particles,void in spacer,and particle on the surface of solid insulation) were designed and fabricated.A wideband UHF sensor and an amplifier were applied to obtain UHF *** on the characteristics of the five different defects,nine meaningful parameters which were independent of the phase of the applied voltage were extracted from the PD samples and then *** this paper,Fisher discriminant analysis(FDA),a pattern recognition algorithm,was applied for the purpose of classifying the *** this way,there was no need to set complicated parameters and kernel function,and the total discrimination accuracy of test samples was 97.6%.It indicates that based on the nine especial parameters,the typical defects in GIS can be identified exactly by means of *** the analysis method could be possibly regarded as a universal classification method.

关键词： Fisher判别分析绝缘缺陷局部放电 GIS 气体绝缘开关地理信息系统在线监测识别算法

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Research on the application of WIA industrial wireless technology in the substation auxiliary control system

Research on the application of WIA industrial wireless techn...

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Chinese control Conference (CCC)

作者： Ting Yuan Shijie Cui Qingqi Zhao Zhijun Shang Peng Zeng Qiang Gao Ping Li Tao Wang Gang Wang State Grid Liaoning Electric Power Company Limited Panjin Power Supply Company Panjin China Shenyang Institute of Automation Chinese Academy of Sciences Shenyang Liaoning CN Key Laboratory of Networked Control Systems Chinese Academy of Sciences Shenyang China State Grid Liaoning Electric Power Supply CO. Ltd. Shenyang China State Grid Liaoning Electric Power Company Limited Electric Power Research Institute Shenyang China

This paper presents a new substation auxiliary control system communication scheme based on WIA industrial wireless technology. The structure and operation principle are introduced, and the technical difficulties and solutions of the WIA industrial wireless technology in substation auxiliary control system application are analyzed from the network protocol and hardware design. The validity of the schema has been verified through the practical application in the pilot project.

关键词： Substations control systems Wireless communication Wireless sensor networks Monitoring Temperature sensors Interference

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Development and Application of DC Partial Discharge Test System

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高电压技术 2013年第8期39卷 1981-1987页

作者： NIE Dexin SHA Yanchao ZHOU Yuanxiang WU Zhirong DENG Jiangang State Grid Electric Power Research Institute Wuhan 430074 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

Direct current (DC) partial discharge (PD) test has drawn extensive attention from world-wide electric power research institutes in recent years. However, presently, no DC PD detection device on the market has the statistical function. Thus, we developed a test system for PD detection under DC voltage, which is characterized by strong anti-jamming capability, continuous high-speed real-time data acquisi- tion and effective, complete detection of DC PD signals. The DC PD mechanism, as well as the measuring principles, software system, and hardware design of the test equipment were introduced. Adopting typical electrode pairs, we tested the statistical spectrum of PD under DC voltage. The main difference in statistical spectrums between parallel plate electrodes and needle-plate electrodes was that the time interval between two consecutive discharges for needle-plate electrodes has obviously larger variation range than that for parallel plate electrodes, which could be the convincing proof for distinguishing the type of electrodes under DC PD. Practical results indicate that the proposed sys- tem can measure time domain signals of DC PD of oil-paper insulation effectively and promptly, and it can be used to determine and detect defects in DC power transmission equipment.

关键词：局部放电信号直流电压测试系统开发针板电极应用检测装置实时数据采集

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Lightning overvoltage suppression to UHV power transformer by ferromagnetic ring

Lightning overvoltage suppression to UHV power transformer b...

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作者： Zhang, Xiao He, Jinliang State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

Lightning overvoltage protection is of great importance to the safety of devices in UHV GIS. In practice, insulation failure of UHV transformer due to lightning strike is often reported. The widely used UHV metal-oxide arresters can suppress the magnitude of lightning overvoltage but lack effectiveness on alleviating the steepness. A new protection method is proposed in this paper using ferromagnetic ring as supplement to the arresters in suppressing lightning overvoltage within UHV GIS. Moreover, equivalent model based on the characteristic of ferromagnetic material and factual dimensions of the ring is established. simulation of an actual 1000 kV GIS is carried out to thoroughly evaluate the lightning overvoltage suppressing effect of ferromagnetic rings with different materials and structure parameters. © 2012 Elsevier B.V. All rights reserved.

关键词： power transformers

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A fast transient simulation model of DFIG based on the piecewise averaging method

A fast transient simulation model of DFIG based on the piece...

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2nd IET Renewable power Generation Conference, RPG 2013

作者： Feng, G. Xu, Y. Chen, Y. Gao, H. Chen, L. State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781849197588

Due to the power electronic devices in doubly fed induction generators (DFIG), it is very time consuming to simulate the electromagnetic transients of DFIG using its detailed model. Thus it is necessary to have appropriately simplified model of DFIG that maintains desirable accuracy. In this paper, the piecewise averaged model of PWM converters is introduced and applied to the modelling of DFIG. The proposed model divides the simulation time interval into switching periods and recalculates the averaged state equations of PWM converters in each switching cycle. In addition, a predictorcorrector based EMTP algorithm is designed to iteratively solve the model. Instead of treating switching events at the time points when they happen, the new algorithm solves all the switching instants in a switching cycle at the same time, which avoids frequency modification of the system conductance matrix and speeds up EMT simulations of DFIG. simulation results of a single-machine infinity bus system with a DFIG show that the proposed model and algorithm can achieve satisfactory accuracy and efficiency.

关键词： Equations of state

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control of parallel grid-connected photovoltaic inverters with common dc bus

Control of parallel grid-connected photovoltaic inverters wi...

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2nd IET Renewable power Generation Conference, RPG 2013

作者： He, F. Zhao, Z. Yuan, L. Lu, T. State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781849197588

This paper proposes a hierarchical control scheme for parallel grid-connected PV inverters with a common dc bus. Droop control and group coordination are implemented to achieve equal power sharing between inverters as well as zero steady-state error for dc voltage regulation. The implementation is specifically designed for distributed control to promote modularization and system reliability. Experimental results have verified that the proposed scheme is effective.

关键词： Electric power transmission networks

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