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International Universities Power Engineering Conference (UPEC)

作者： Kun Liu Xinzhou Dong Zhiqian Bo State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China AREVA T&D Automation슠and Information Systems Staffordshire UK

Non Conventional Instrument Transformer (NCIT) and IEC 61850 are crucial technologies in digital substations. But they bring some new uncertainties to protection IEDs, especially the time synchronization issue in current differential protection. The paper analyzes the time delay of transferring sampled values from NCIT to current differential relay in NCIT and IEC61850 based digital substation, then finds out the delay-non-deterministic problem, at last presents a novel current differential protection scheme by using Phase-Locked Loops (PLL ) technology.

关键词： Substations Delay effects Synchronization IEC Phase locked loops Data communication Ethernet networks

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A comprehensive platform for high-voltage and middle-voltage urban distribution system planning

A comprehensive platform for high-voltage and middle-voltage...

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China International Conference on Electricity Distribution, CICED

作者： Jun Xiao Bo Wang Cheng-shan Wang Feng-qing Jiang Fang-di Shi Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Nankai District 300072 China Tianjin University Tianjin Tianjin CN Shanghai Municipal Electric Power Company 200122 China

To adapt the needs of the rapid development and more frequent construction or reconstruction of urban distribution network in China, this paper proposes a comprehensive computer-supported planning software system, which is called planning platform. It is different from the traditional decision-making system which only plays a role as an analysis and decision-making support tool for planning engineers. Moreover, it not only proposes a co-operational platform for all members directly or indirectly involved in distribution planning, but also provides access to information in the planning management. Based on the comprehensive process of the superior and the subordinate network, which is compared with the traditional planning process, it can commendably solve the urban network all-voltage series' comprehensive planning problems, make the distribution network's whole optimization, avoid something like N-1 spare redundant, inharmonious power supply, and achieve the purpose of sufficiently exhuming the network's power supply ability and global economy optimization. This platform's development can optimize present planning process, build multi-section's co-operative environment of the planning, standardize the planning data's collection and distribution, and strengthen the planning management system. The comprehensive platform for urban distribution system is the development and tendency of the planning software and the computer assistant planning.

关键词： Urban planning Power system planning Process planning Distributed computing Decision making Power system management Power supplies Computer networks Software systems Environmental management

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Medium voltage distribution system reliability calculation with the consider of high voltage distribution system and substation

Medium voltage distribution system reliability calculation w...

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3rd International Conference on Electric Utility Deregulation and Restructuring and Power Technologies (DRPT 2008), vol.1

作者： Chengshan Wang Yue Lv Jun Xiao Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University TJU Tianjin China

According to the operational features of distribution network, the paper presents a method to calculate the distribution system reliability that also considers multi-layers failure. Based on the regular reliability calculation, the results are promoted. Firstly, the distribution system is divided into different parts by different voltage level. Secondly, based on the characteristics of the distribution system, a comprehensive evaluation method, which combines the high and medium voltage distribution system and the substation's influence, is taken into account. Through integration of the boundary condition, using the series and parallel formula, the promoted results are calculated. An example demonstrates the effectiveness and the accuracy of the method. It is a method which can be utilized in the cases of general index, and also satisfies with the various needs of the reliability calculation.

关键词： Comprehensive Reliability Assessment Distribution system

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Comprehensive method on evaluation of distribution network planning

Comprehensive method on evaluation of distribution network p...

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International Conference on Electric Utility Deregulation and Restructuring and Power Technologies (DRPT)

作者： Jun Xiao Yanyan Cui Fengzhang Luo Mingzhi Liu Jianmin Wang Yinong Li Yubo Gao Saiyi Wang Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University TJU Tianjin China Tianjin Electric Power Corporation Tianjin China SMEPC Urban Power Supply Company Shanghai China Urban Power Supply Company SMEPC Shanghai 200122 China

Planning is vital for the development of power system; and the quality of planning has direct influence on security, reliability and economy of the power system in the future. Therefore, it is urgently needed to study quantitative evaluation method for distribution network planning. First, this paper proposes a practical comprehensive hierarchy and method on evaluation of distribution network planning. Second, the implementation steps for the evaluation of planning network are given, which include the determination of indices hierarchy and the evaluation of planning. In the end, this paper takes 10 kV network distribution planning of a district in China for example in order to illustrate the specific evaluation steps and methods based on the hierarchy, at the same time, the case shows that the evaluation method has strong feasibility and practicability. The planning evaluation hierarchy and method proposed in this paper can not only seize the key elements influencing the characteristics of network planning, but also describe the planning integrally and quantitatively, and possess significant engineering practicability.

关键词： Power system planning Power system reliability Power system security Urban planning Meeting planning Laboratories Power system simulation control system synthesis Power system measurements control engineering education

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Prediction of Instability Separation Modes and Its Application in Practical Dynamic Security Region

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Transactions of Tianjin University 2007年第3期13卷 157-162页

作者：曾沅余贻鑫王红梅闵亮张沛 LEES T Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Electrical Power Research Institute

The transient critical boundary of dynamic security region (DSR) can be approximated by a few hyper planes correlated with instability separation modes. A method to fast predict instability separation modes is proposed for DSR calculation in power injection space. The method identifies coherent generation groups by the developed K-medoids algorithm, taking a similarity matrix derived from the reachability Grammian as the index. As an experimental result, reachability Grammian matrices under local injections are approximately invariant. It indicates that the generator coherency identifications are nearly consistent for different injections. Then instability separation modes can be predicted at the normal operating point, while average initial acceleration is considered as the measure of the critical generator group to amend the error. Moreover, based on these predicted instability separation modes, a critical point search strategy for DSR calculation is illustrated in the reduced injection space of the critical generators. The proposed method was evaluated using New England Test system, and the computation accuracy and speed in determining the practical DSR were improved.

关键词： instability separation mode dynamic security region K-medoids algorithm reachability Grammian

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PSIM and SIMULINK Co-simulation for three-level adjustable speed drive systems

PSIM and SIMULINK Co-simulation for three-level adjustable s...

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IPEMC 2006: CES/IEEE 5th International Power Electronics and Motion control Conference

作者： Yongchang, Zhang Zhengming, Zhao Baihua Liqiang, Yuan Haitao, Zhang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)1424404487

Applying co-simulation technology is a very important trend in power electronics simulation, which can make full use of the merits of different software to improve the efficiency of building up a system. In this paper, a simulation platform for three-level adjustable speed drive (ASD) based on co-simulation of PSIM and SIMULINK is presented, which includes the interface between PSIM and SIMULINK, main circuit in PSIM, space vector pulse width modulation (SVPWM), dead time and minimum pulse width, view of output voltage and its Fourier analysis in SIMULINK Based on this platform, the cause of large current when motor starts is studied. simulation and experimental results show that the minimum pulse width contributes a lot for the large starting current of the ASD. In conclusion, applying the simulation platform introduced in this paper, the dynamic behavior of the three-level ASD can be easily studied, which reduces the cost and improves efficiency at the same time compared to hardware investments, and may help to realize the optimal design of the ASD in practice. © 2006 IEEE.

关键词： Efficiency

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Dynamic Equivalent Circuit Design In Three-level High Voltage Inverters Based On Functional Model of IGCT

Dynamic Equivalent Circuit Design In Three-level High Voltag...

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Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition (APEC 07), vol.2

作者： Hua BAI Zhengming Zhao Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

The integrated gate commutated thyristors (IGCTs) are commonly used for construction of high voltage three-level PWM controlled voltage source converter/inverters. When the output voltage is greater than the maximum rated voltage, IGCTs are connected in series. To ensure the safe and reliable operation of the converter/inverters, special measures are required to equalize the voltages across the IGCTs connected in series. An effective method for balancing voltages is to use resistors for static voltage balancing and RC snubber circuits for dynamic voltage balancing. However, most of the previous research work reported in the literature focused on the dynamic circuit design for converters of the BUCK topology. Trade off is made only between the performance of dynamic voltage balancing and the turn-on loss without any consideration of di/dt endurance and any procedural steps, which makes the design procedure not suitable for converters of the three-level topology. Based on a functional model of IGCTs, this paper presents a procedure for optimum design of the dynamic voltage balancing circuit for a 6 kV/1250 kW inverter. The specific transient processes in the three-level topology with dynamic snubber circuit are simulated and the mechanisms are analyzed, which is absent in the previous work.

关键词： IGCT Dynamic equivalent circuit Three-level inverter Dead band

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Safe Operating Area of High Power Three-level Neutral Point Clamped Voltage Source Inverters Equipped with IGCTs

Safe Operating Area of High Power Three-level Neutral Point ...

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International Conference on Electrical Machines and systems 2007(ICEMS2007)(第十届国际电机与系统会议)

作者： Liqiang YUAN Zhengming ZHAO Fanbo HE Mohd Eltawil State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University China

To design and analyze the behavior of high power inverter, the definition and application of the inverter's own safe operating area (SOA) are presented in this paper. The relation between the switch devices behaviors and the other components of the inverter is playing a key role in the description of the novel SOA. Based on the proposed idea, the optimization of a real 1.25MW/3.3kV inverter equipped with IGCTs is presented and analyzed. The corresponding experimental results are shown.

关键词： Voltage Pulse width modulation inverters Semiconductor optical amplifiers Switches Induction motors Power harmonic filters Power system simulation Variable speed drives Circuits Topology

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Visible target imaging system validation for hardware-in-the-loop

Visible target imaging system validation for hardware-in-the...

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Summer Computer simulation Conference 2006, SCSC 2006, Part of the 2006 Summer simulation Multiconference, SummerSim 2006

作者： Yu, Hong He, Qiuru Lei, Jie Du, Huijie Zhang, Ying State Key Laboratory of Control System Simulation Beijing Simulation Center 52 Yongding Road Beijing China

ISBN: (纸本)9781622763528

This paper describes visible target imaging simulation system and validation activities at Beijing simulation Center. The target size and position models and target energy output are validated here. The target size validation is based on comparison of visible seeker data collected in the HWIL simulation to theory calculation;the target position validation is based on comparison of visible seeker data collected in the HWIL simulation to demands setting values;and the target energy validation is based on comparison of gray levels from the projector to the luminance provided by an institute of targets property research or by visual inspection.

关键词： Hardware-in-the-loop simulation

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Analyzing the energy spectra of ion beams emitted from x-pinch plasma

Analyzing the energy spectra of ion beams emitted from x-pin...

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IEEE International Conference on Plasma Science (ICOPS)

作者： Xiaobing Zou Rui Liu Xinxin Wang Guixin Zhang Chengmu Luo Min Han Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

Summary form only given. Between the output electrodes of a 500 kV/400 kA/100 ns pulsed-power generator, two Al wires each with diameter of 10-100 mum crossing and touching at a single point constitute an "x" shape load. The cross position explodes first and then pinches axially to form so-called X-pinch plasma as current is delivered to the "x" wires. In order to analyze the energy spectra of ion beams emitted from x-pinch, a compact Thomson spectrometer was designed and constructed. It consists of an entrance window, a pair of small permanent magnets, an exit pinhole, and a high sensitive nuclear track detector of CR-39 plastic plate. Ion beams experience deflections in the electromagnetic field, and then hit the target (CR-39 plastic) at different positions and form craters, then the craters form different parabolic track with different ratio of ion mass to ion charge. By counting the track density of the parabolas, charge state resolved energy spectra of ion beams were obtained

关键词： Ion beams Plasmas Target tracking Wires Plastics Electrodes Pulse shaping methods Pulse generation Shape Magnetic analysis

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