检索结果-内蒙古大学图书馆

International Symposium on Electromagnetic Compatibility, EMC EUROPE 2012

作者： Xiao, Li Yu, Zhanqing Chen, Shuiming Zhang, Bo Zeng, Rong Zhuang, Chijie Zeng, Yang Yu, Xiaoying Zhang, Qian State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China Research Institute Zoomlion Heavy Industry Science and Technology Development Co. Ltd. Changsha Hunan China

ISBN: (纸本)9781467307185

The Electromagnetic Compatibility (EMC) is a major issue for the truck crane designing, due to the large dimension. The conducted disturbance sources of truck crane was measured under stable conditions, the time domain characteristics of possible conducted disturbance sources was analyzed, and typical waveforms were concluded to solve the EMC (Electromagnetic Compatibility) issue. The electromagnetic disturbance characteristics at different test points under different operation conditions were compared, and the influence of different factors was studied. The amplitude and frequency parameters of the major disturbance sources were compared with the standard immunity test pulses suggested by ISO7637-2. The differences between them indicate that the extant standard might not apply to the test of the truck crane. The presented results could form a basis for the development of a special standard for the EMC test of the truck crane and further relevant EMC research. © 2012 IEEE.

关键词： Electromagnetic compatibility

来源：评论

学校读者我要写书评

暂无评论

Influence of the Structure Dimension of GIS on the Partial Discharge

Influence of the Structure Dimension of GIS on the Partial D...

引用

IEEE International Conference on Condition Monitoring and Diagnosis

作者： Dengwei Ding Wensheng Gao Weidong Liu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University

ISBN: (纸本)9781467310192

Partial discharge (PD) monitoring plays an important role in the online maintenance of the gas insulated switchgear (GIS). In recent years, the ultra high frequency (UHF) method for PD detection arouses great interest of many researchers because of the high sensitivity and anti-interference capability. The coupling of UHF signal is the key to the detection of partial discharge in GIS. The structure size of GIS has great impacts on the PD signal, because the cutoff frequency of the high order mode of the electromagnetic (EM) wave depends on the diameters of the inner conductor and enclosure. In this paper, the influence of the inner conductor diameter is investigated by varying the center conductor size. The inner coupler is adopted to receive the partial discharge signal, and two types of PD sources are tested in the experiment. Firstly, the amplitude and the duration of the time domain signal and the frequency spectrum are focused, and their variations with the size of inner conductor are analyzed. Besides that, In order to research the changes of the TEM mode component and the high order mode component, low pass (LP), band pass (BP) and high pass (HP) filters are applied to process the PD signals, and the cumulative energy rates are calculated to indicate the energy distribution. In addition, a simulation using the FDTD method is conducted for comparison with the experimental results, and it indicates that the results of experiment and simulation are almost consistent.

关键词： Partial discharge Ultra high frequency Structure size of GIS Frequency spectrum The cumulative energy rate FDTD

来源：评论

学校读者我要写书评

暂无评论

Fault classification rules extraction of wind turbine based on C4.5 algorithm

Fault classification rules extraction of wind turbine based ...

引用

Prognostics and Health Management Solutions Conference - PHM: Driving Efficient Operations and Maintenance, MFPT 2012

作者： Chen, Jie Jiang, Dongxiang Yang, Wenguang Deng, Xiaowen Feng, Yongxin State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Beijing 100084 China Electric Power Institute Guangdong Grid Company Guangzhou 510080 China

Distinguishing fault types in early time can prevent wind turbines from breaking down. C4.5 algorithm, different from ID3 algorithm, which can deal with continuous parameters, should be a choice fault diagnosis method of wind turbine. This paper strives to extract fault classification rules of wind turbine based on data collected from a small wind turbine in laboratory using C4.5 decision tree and validate the rules extracted using another set of data. According to the solution, fault types such as mass imbalance of rotor, aero-dynamic asymmetry, yaw misalignment, gearbox and bearing fault and so on can be distinguished by the method presented in this paper.

关键词： Wind turbines

来源：评论

学校读者我要写书评

暂无评论

power Losses in Two- and Three-Level Three Phase Photovoltaic Inverters Equipped with IGBTs

Power Losses in Two- and Three-Level Three Phase Photovoltai...

引用

International Conference on Electrical Machines and systems

作者： Zhiping Chen Liqiang Yuan Zhengming Zhao Xiaoying Sun State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University

ISBN: (纸本)9781467323277

To increase efficiency is an essential target in photovoltaic (PV) power generation system. The losses of the whole system consist of several parts. This paper focuses on the losses of the hard-switching devices. An improved method to calculate the device losses is proposed. And influences of different factors like DC link voltage, input power, switching frequency and power factor on the losses are considered. Then this paper compares the losses of conventional two-level inverter and of diode-clamped three-level inverter to provide the evaluation of power losses under different working conditions. This is helpful to design and optimize a certain PV inverter. Calculating results based on an actual three phase 10kW PV inverter are presented.

关键词： Loss-calculation IGBT Three-level Photovoltaic

来源：评论

学校读者我要写书评

暂无评论

Substation-dispatch center two-level distributed state estimation

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2012年第7期36卷 44-50+91页

作者： Li, Qingxin Sun, Hongbin Wang, Jing Zhang, Boming Wu, Wenchuan Guo, Qinglai State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

A two-level distributed state estimation method for substation-dispatch center is proposed. After zero impedance three-phase state estimation based on KCL has been applied in substation, up load ripe data are treated in dispatch center level and the single-phase state estimation for all grid implemented. The detailed discussions about the architecture, algorithm, ripe data transmission, time setting and period selection, transmission protocol and transition scheme for the method are given. The results of calculation example show that this method is in favor of simultaneously identifying three-phase bad data and topology error, reducing communication burden, and increasing the reliability of the dispatch center state estimation for all grid. © 2012 state Grid Electric power Research Institute Press.

关键词： state estimation

来源：评论

学校读者我要写书评

暂无评论

Multi-source information based current matching state estimation for distribution network

引用

Dianli Xitong Zidonghua/Automation of Electric power systems 2012年第16期36卷 53-57页

作者： Ju, Yuntao Wu, Wenchuan Cheng, Xueqi Zhang, Boming Sun, Hongbin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China Weifang Power Supply Bureau Shandong Provincial Power Corporation Weifang 261000 China

By taking into account the real-time measurement with low redundancy and of only partial current in distribution systems and referring to the quasi-real-time current measuring data of the metering system, the current matching technique is proposed to solve the distribution network state estimation. The matching current equations in the sense of optimal estimation and its systematic solution are deduced. Based on the assumption that the load power factor is stable, a quasi-real-time measurement generating method is proposed for loads. With boundaries demarcated by real-time current measurement, the distributed network is divided into several measured areas and current matching state estimation is made for each area. Numerical tests and results of an actual system show that the method proposed can satisfy the real-time application demand of the distribution system. ©2012 state Grid Electric power Research Institute Press.

关键词： state estimation

来源：评论

学校读者我要写书评

暂无评论

X-ray backlighting of wire expansion and plasma merging of z-pinch load with 10-40kA/wire

X-ray backlighting of wire expansion and plasma merging of z...

引用

IEEE International Conference on Plasma Science (ICOPS)

作者： Xinlei Zhu Xiaobing Zou Ran Zhang Shen Zhao Haiyun Luo Xinxin Wang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

It is well known that the evolution of wire array z-pinch load can be divided into several phases: wire explosion, inter-wire plasma merging, implosion and stagnation. In this paper, experiments with x-pinch backlighter to study the initial wire explosion and inter-wire plasma merging were performed on the pulsed power generator PPG-I at Tsinghua University. An x-pinch (13-25μm Mo and 5-18μm Wu wires) used as soft x-ray source was installed in the centre between the output main electrodes of PPG-I generator, and the object z-pinch load was installed in one of the return current posts. The object z-pinch load consists of 2-4 tungsten wires of 5-18 μm diameter, 12 mm long, and 2 mm spacing between wires. The evolution images of wire explosion and inter-wire plasma merging were recorded with high resolution x-ray film, which was covered with a mass step-wedge filter to calibrate the mass density distribution of wire explosion and inter-wire merging plasma. Based on extensive discharge tests, the time sequence of backlighting images of z-pinches was obtained. In the paper, we also discussed how to determine the interface between high-density wire core and low-density surrounding plasma, and then presented the expansion rates of high density wire core and the mass density distribution of inter-wire plasma under different z-pinch current.

关键词： Wires Plasmas Merging Explosions Educational institutions Generators Radio access networks

来源：评论

学校读者我要写书评

暂无评论

Application of Fuzzy-Rough Set theory and improved SMO algorithm in aircraft engine vibration fault diagnosis

Application of Fuzzy-Rough Set theory and improved SMO algor...

引用

Prognostics and System Health Management Conference (PHM)

作者： Hongzhi Xu Dongxiang Jiang Lei Liang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457719097

Aircraft engine is an important component of the airplane, which lifespan and reliability have directly influence to flight safety. Vibration analysis is an effective fault diagnosis method for airplane's mechanical construction fault. Several typical vibration faults have drawn from the vibration analysis on the basis of fault mechanism in aircraft engine, and the standard vibration fault-symptom (Fuzzy Membership) relationship table have constructed based on Fuzzy Mathematic theory in this paper. Sample data are simulated on the basis of this table. Sequential Minimal Optimization (SMO) is a fast algorithm for training Support Vector Machines (SVM). The simulated result showed a great improvement on computation efficiency by selecting double threshold parameter for SMO algorithm than single threshold. In order to examine the algorithm's effect applying in the aircraft engine fault diagnosis, Radial Basis Function (RBF) Neural Network, C4.5 Decision Tree, SVM (chunking), Platt's SMO and Improved SMO algorithm are applied to the training data and test data. It is shown that the Improved SMO algorithm displayed superior comprehensive performance. Finally, the vibration fault feature is reduced based on Fuzzy-Rough Sets theory. The research shows that the Improved SMO algorithm is quicker than other algorithm in aircraft engine fault diagnosis with the reduced feature attributes, and its accuracy is high.

关键词： Vibrations Accuracy Safety Aircraft Classification algorithms Support vector machines

来源：评论

学校读者我要写书评

暂无评论

Design and implementation of photovoltaic lighting system with high luminous efficacy LEDs

Design and implementation of photovoltaic lighting system wi...

引用

International Conference on power Electronics and Motion control (IPEMC)

作者： Liqiang Yuan Zhiping Chen Xianlai Hu Junjie Ge Zhengming Zhao State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457720857

With the background park lighting application, and based on the characteristics of advanced devices in the system, this paper studies the photovoltaic (PV) light emitted diode (LED) lighting system in three main aspects, which are the design of the whole system, hybrid control strategy combining the maximum power point tracing (MPPT, for PV panels) with the energy management(for battery), and LED driving and dimming. Taking the example of an actual 50W high luminous efficacy LED system, the design, implantation and experiments are described in detail. In addition, the long-term measurement results in real environment are illustrated in this paper.

关键词： Batteries LED lamps Switches Pulse width modulation Discharges (electric)

来源：评论

学校读者我要写书评

暂无评论

power transformer condition assessment by on-line monitoring and trend analysis

Power transformer condition assessment by on-line monitoring...

引用

IASTED International Conference on power and Energy systems and Applications, PESA 2012

作者： Xie, Qijia Gao, Shengyou Zhang, Hailong Dai, Wen Ruan, Ling Nie, Dexin Lu, Wenhua Key Laboratory of High-Voltage Field-Test Technique of SGCC Hubei Electric Power Testing and Research Institute Wuhan China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China State Grid Electric Power Research Institute Wuhan China School of Electrical Engineering Wuhan University Wuhan China

power transformer condition assessment is the basi of condition-based maintenance and plays a very important role in carrying assets management and risk assessment for power system. As the heart of transmission and transformation system, power transformer's condition has close relation with many factors, such as the production quality of itself, operation environment and so on. This paper analyzes some variables which could represent the transformer's condition, including the data from preventative test, factory test and commission test, diagnostic test, on-line detection and monitoring, routine inspection, operation history, family defection and environment information. Some parameters which have representation are chosen as the condition variables. Artificial neuron network (ANN) and Dempster-Shafer (D-S) evidence theory are adopted to form the multiparameter information fusion condition assessment model. Besides the static value, the change trends of some parameters are considered as an independent evidence section. Cooperating with on-line monitoring, it will be helpful to improve the accuracy and efficiency of condition assessment.

关键词： power transformers

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：