检索结果-内蒙古大学图书馆

IEEE Conference on Vehicle power and Propulsion (VPPC)

作者： Hu Sideng Zhao Zhengming Zhang Yingchao Wang Shuping State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418480

The communication protocol is important for applying adjustable speed drive (ASD) systems to an industry network. This paper proposes a novel scheme of communication system for the ASD system based on Modbus protocol. The most remarkable advantage of the approach lies in the tradeoff between performance and economic cost for a power converter system. The overall system is built on master-slave structure and easy for interacting with other networks. An additional study on the cyclic redundancy check (CRC) in Modbus RTU is introduced to obtain the optimization design in the actual application and the optimization method in software design is also presented. The performance of the communication system obtained from experiment conducted on the 15 kW ASD system validates the effectiveness of the proposed design method.

关键词： Variable speed drives Protocols Cyclic redundancy check Communication industry power system economics power generation economics Costs Master-slave Design optimization Application software

来源：评论

学校读者我要写书评

暂无评论

Investigation and Analysis of the Influence of Magnetic Wedges on High Voltage Motors Performance

Investigation and Analysis of the Influence of Magnetic Wedg...

引用

Vehicle power and Propulsion Conference

作者： Shuping Wang Zhengming Zhao Liqiang Yuan Buyao Wang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Anhui Electric Power Research Institute Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation EquipmentTsinghua University Beijing China Corporation Company Ltd. Of XiangTan Electric Machine XiangTan China

ISBN: (纸本)9781424418480;9781424418497

To weaken the pulsation of the harmonic magnetic field and improve the wave of the air-gap magnetic field in high voltage motors because of their open slots, magnetic slot wedge should be imbedded into the slot opening. In the paper, through analyzing the air-gap magnetic field distribution of large-scale motors affected by embedding magnetic slot wedges in open slots, the influence of magnetic slot wedge on the motor parameters and performance is discussed in theory. The finite element analysis (FEA) and the experiment results were given, which not only proves the validity of the analysis in the paper, also through the simulation results the proper parameters of magnetic slot wedges for best performance of motors were concluded, which provides a theoretical reference for the manufacturers when choosing or processing magnetic slot wedges.

关键词： Air-gap Magnetic Field Magnetic Slot Wedges Motor Performance

来源：评论

学校读者我要写书评

暂无评论

Optimal design of SVC-based subsynchronous damping control using genetic and simulated annealing algorithm

Optimal design of SVC-based subsynchronous damping control u...

引用

International Conference on Information and Automation (ICIA)

作者： Tingzhi Yang Xiaorong Xie Shiyu Liu Donghui Zhang State Key Laboratory of security control & simulation of power systems and large-scale generation equipments Department of Electrical Engineering Tsinghua University Beijing China

In this paper, an optimal approach based on genetic and simulated annealing algorithm (GASA) is prosposed to design more effective and robust subsynchronous damping control (SSDC) of Static Var Compensator (SVC) for multimodal SSR damping improvement. A practical multi-machine series compensated power system suffering multimodal SSR has been studied to demonstrate the effectiveness of the approach. The developed SSDC comprises independent modal control path, each with separate feedback gains and phase-shifts, to damp different torsional mode. The problem of simultaneously tuning all the control parameters for robust stabilization of multiple torsional modes over various system conditions is formulated into a standardized constrained optimization problem. With the proposed GASA, the problem is efficiently solved and the SVC SSDC is optimized. Both eigenvalue analyses and electromagnetic simulations have been conducted on the test system to validate the approach and the designed SVC-based SSDC.

关键词： Static VAr compensators Damping Generators Gallium power system dynamics Optimization power systems

来源：评论

学校读者我要写书评

暂无评论

Effects of morphology on movement of space charge packet in polyethylene

引用

Gaodianya Jishu/High Voltage Engineering 2008年第11期34卷 2385-2389页

作者： Zhou, Yuan-Xiang Wang, Yun-Shan Wang, Ning-Hua Sun, Qing-Hua Nie, Qiong Liang, Xi-Dong Guan, Zhi-Cheng State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept of Electrical Engineering Tsinghua University Beijing 100084 China China Electric Power Research Institute Beijing 100085 China

Polyethylene is a major kind of internal insulating material. This paper measured the space charge phenomenon in low-density polyethylene (LDPE) by the pulsed electro-acoustic (PEA) method and observed the space charge packet. This research got the LDPE films of different morphology by different annealing rate and discussed the effect of morphology and electrical field stress changing on space charge packet's moving velocity. The research shows that morphology of LDPE affects the velocity of space charge packet remarkably;bigger crystallinity results in lower velocity of space charge packet. The intensity of electrical field has little affection to the velocity. The average mobility of different crystallinity under different electric field was calculated. The relationship between crystallinity and mobility was found. The results further demonstrate there are inherent relationships among higher crystallinity, more space charge accumulation, lower mobility and deeper trap depth. Lower mobility and deeper trap depth have a monotone relationship.

关键词：空间电荷空间电荷包聚乙烯微观形态迁移率 PEA

来源：评论

学校读者我要写书评

暂无评论

Breakdown processes of solid composite insulation system with defects under high frequency

Breakdown processes of solid composite insulation system wit...

引用

Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Q. Nie Y.X. Zhou X.L. Xing Y.S. Wang State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept of Electrical Engineering Tsinghua University Beijing China

Behaviors of composite insulation system are strongly affected by the performance of interface between dielectrics, which mostly correlates to the direction of applied electrical field and the frequency of applied voltage. In this paper, experiments were carried out to study the breakdown characteristics of solid composite insulation system, consisted of a polyethylene (PE) film (with a copper needle electrode) and a glass slice. A sine wave power supply with a frequency range from 50 Hz to 100 kHz was established to fit our purposes. Voltage was smoothly raised from 0 kV to 5 kV. The processes of breakdown can be divided into four stages: (1) Electrical tree inception and propagation in polyethylene; (2) Sliding discharge along the interface between polyethylene and glass; (3) Streamer across the glass; (4) Return streamer initiation from the ground electrode and breakdown. A model was established to analyze the mechanism of sliding discharge between solid dielectrics. The influence of frequency on thermo effect is considered as the main causes of the experiment results, which can well explain the reason of insulation premature inactivation in high-frequency electrical equipment.

关键词： Electric breakdown Solids Frequency Dielectrics and electrical insulation Polyethylene Glass Voltage Electrodes Plastic films Copper

来源：评论

学校读者我要写书评

暂无评论

Study of Non-Conventional Instrument Transformer and IEC61850 impact on current differential protection

Study of Non-Conventional Instrument Transformer and IEC6185...

引用

IEEE/PES Transmission and Distribution Conference and Exposition: Latin America

作者： K. L. S. Shenxing X. Dong Z. Bo State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Tsinghua University Beijing Beijing CN 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 Stafford 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 Ethernet networks Phase locked loops IEC Synchronization Data communication

来源：评论

学校读者我要写书评

暂无评论

Current differential protection based on Non-Conventional Instrument Transformer and IEC61850

Current differential protection based on Non-Conventional In...

引用

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

来源：评论

学校读者我要写书评

暂无评论

Novel active damping control scheme for a three-phase active rectifier with LCL-filter

引用

Diangong Jishu Xuebao/Transactions of China Electrotechnical Society 2008年第9期23卷 86-91页

作者： Huang, Yuqi Jiang, Xinjian Qiu, Arui State Key Lab. of Security Control and Simulation of Power Systems and Large Generation Equipments Tsinghua University Beijing 100084 China

A novel active damping control scheme is developed to eliminate stability problems arisen in the current control of a three-phase voltage source active rectifier (VSR) with LCL-filter. A converter side inductance voltage feedback loop is introduced in the traditional voltage oriented control to stabilize VSR. A simplified discrete model including the current control loop and LCL-filter is established with one sample delay, considering time delays induced by S/H (sampling and holding), processing and modulation. The amplification coefficient of the converter side inductance voltage feedback loop is tuned up to change the unstable poles of LCL-filter. Parameter estimate methods are used to remove unnecessary sensors. simulation and experiment of VSR with LCL-filter demonstrate the proposed active damping control scheme and the stability analyses.

关键词： Inductance

来源：评论

学校读者我要写书评

暂无评论

Maximum flow algorithm based on adjustment of net flow on nodes and its application

引用

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2008年第SUPPL.期28卷 31-34页

作者： He, Guang-Yu Sun, Ying-Yun Chen, Chao State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

For calculating the maximum capacity transported from source node to sink node in a network, a maximum flow algorithm was proposed. Based on the concept of net flow on nodes (NFN) and layered increment network (LIN), the plus flow process (PFP) and minus flow process (MFP) on LIN were defined. By performing PFP and MFP on NLP over and over, the maximum flow problem was solved when the sink node can't get a mark again. Compare to the existing max flow algorithm, the proposed method needs no complex data structure in processing, which makes the algorithm implemented easily. Based on the algorithm, a thermal economic dispatch software package which includes fixed electricity plant was developed and had been put into practice and had a good performance. Furthermore, the algorithm runs in O(n2m) (n, m is the number of nodes and arcs of the network) was proved.

关键词： Scheduling

来源：评论

学校读者我要写书评

暂无评论

Eigenvalue analysis of multi-mode sub-synchronous resonance for multimachine plant-to-grid transmission systems with fixed series compensation

引用

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2008年第SUPPL.期28卷 13-18页

作者： Zhang, Shu-Qing Xie, Xiao-Rong Yang, Ting-Zhi Liu, Shi-Yu State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

For some domestic large thermal power plants delivering electric energy over long distances, the sub-synchronous resonance (SSR), which is induced by the fixed series compensation (FSC), attracts much attention. Eigenvalue analysis is one of the primary methods to assess the risk and explore the countermeasure. However, for handling multi-machine and multi-mode SSR problems, no practical toolkit based on eigenvalue analysis is on hand for the moment. In this paper, a systematic modeling approach and analysis flows for the purpose of eigenvalue analysis of multimachine plant-to-grid transmission systems with FSC were proposed. The equating technique of machines and networks was presented, and the effect of the q-axis damping windings on the SSR was also explored. The applicability of the proposed method was verified with an actual multimachine system. Furthermore, its advantage over existing SMIB based eigenvalue analysis was clarified by a comparative study between the original multi-machine system and the simplified single-machine system.

关键词： Eigenvalues and eigenfunctions

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：