检索结果-内蒙古大学图书馆

作者： Jiang, Dongxiang Liu, Chao State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing 100084 China

Condition classification has been widely used for assessing equipment status for machine condition monitoring and diagnostics. An engine was fitted with one temperature and two pressure sensors to study the machine conditions in prognostics with an added abnormal state, in addition to the conventional normal and failure states. This work enables a better classification capability in order to predict deterioration in the engine. Information related to three deterioration processes was collected, and preprocessed using singular point elimination, deviation value acquisition, and data normalization. Wavelet transforms were used to extract deterioration features with different mother wavelets. The mother wavelets were selected using t tests to optimize the wavelet selection. The deterioration was related to the amount of anomaly, with the abnormal states defined to distinguish the functional from the failure states. A Learning Vector Quantization (LVQ) neural network was used to classify the machine conditions, including normal, abnormal, and failure states. The results showed that the deterioration features defined using the Daubechies wavelet (db8) most strongly correlated with the original signal, so that the classification accuracy based on the deterioration features was greatly improved. The LVQ classification system had good accuracy for machine condition classification, and was adaptable to various engine conditions. © 2010 IEEE.

关键词： Deterioration

来源：评论

学校读者我要写书评

暂无评论

Improved Blade Tip Timing in Blade Vibration Monitoring with Torsional Vibration of the Rotor

引用

Journal of Physics: Conference Series 2012年第1期364卷

作者： Chao Liu Dongxiang Jiang State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Beijing 100084 People's Republic of China

Due to the complex conditions in rotating machinery, the blades usually encounter fluctuating loads, and failures may occur in the operation. Blade vibration is rarely monitored in the practical rotating machinery in power plants as the traditional blade vibration method using strain gauge method is hard to be applied in long-time and online monitoring. The blade tip timing method is a promising approach to monitor the blade vibration and several special sensors are developed to realize the online monitoring. Based on the traditional blade tip timing method, an improved approach is established in this work. The proposed method can modify the expected arriving time when the torsional vibration exists. The accuracy is therefore improved in the torsional vibration case. Then the blade vibration monitoring with the traditional blade tip timing method and the proposed method are carried out in the test rig in laboratory. The results validate that, the torsional vibration influences the expected arriving time, and the proposed method can modify the expected arriving time and improve the accuracy of the blade vibration monitoring.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Test and Analysis of Conducted Disturbance Sources of the Truck Crane under Stable Conditions

Test and Analysis of Conducted Disturbance Sources of the Tr...

引用

International Symposium on Electromagnetic Compatibility

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

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.

关键词： Truck crane EMC Conducted disturbance source Time domain characteristics Electromagnetic immunity test

来源：评论

学校读者我要写书评

暂无评论

Applicable range analysis of optimized single-terminal fault location algorithm

Applicable range analysis of optimized single-terminal fault...

引用

2011 International Conference on Advanced power system Automation and Protection, APAP 2011

作者： Huang, Tian-Xiao Dong, Xin-Zhou Shi, Shen-Xing Wang, Bin State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781424496198

Impedance method and single terminal travelling wave method are analyzed in paper, applicable scope of optimized solution is presented. Impedance method is of high robustness but low accuracy. Single terminal travelling wave method offers high accuracy but poor robustness. Optimized solution combines these two methods together, takes advantages of both methods. It is a great enhancement to single terminal fault location. This paper analyzed theoretical basis of optimized solution, proposed the calculation algorithm of fault location range using impedance method. Analyses of impedance method and single terminal travelling wave method show that the optimized solution is suitable for engineering application. Error analysis is proved correct by simulation. © 2011 IEEE.

关键词： Location

来源：评论

学校读者我要写书评

暂无评论

Single phase grounding fault location based on frequency domain characteristics of fault current

Single phase grounding fault location based on frequency dom...

引用

2011 International Conference on Advanced power system Automation and Protection, APAP 2011

作者： Jiang, Bo Shi, Shenxing Dong, Xinzhou Wang, Bin State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781424496198

This paper studies the fault current frequency spectrum characteristics of single phase ground fault in ungrounded distribution networks, and the fault location method based on it. Firstly, it analyzes the production mechanism of 2nd major frequency component, and the relationship between the 2nd major frequency component and series resonance frequency of the faulted line. Secondly, from the perspectives of lumped-parameter circuit, the relationship between 2nd major frequency component and fault location is deduced. simulation cases are used to confirm the relationship. Last, the impact of load and initial fault phase angle on the 2nd major frequency component are researched. simulation research proves the feasibility of the fault detection and location method based on frequency domain characteristics. © 2011 IEEE.

关键词： Electric fault location

来源：评论

学校读者我要写书评

暂无评论

Research on the process of power flow transferring and its identification method

Research on the process of power flow transferring and its i...

引用

2011 International Conference on Advanced power system Automation and Protection, APAP 2011

作者： Liu, Kun Dong, Xinzhou Wang, Bin Shi, Shenxing State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781424496198

This paper analyzes the general process of power flow transferring and divides it into four parts: 1) the process of first phase selection after fault occurs;2) the process of selective action at the first time;3) the process of second phase selection and status confirmation;4) the process after status confirmation. It points out that the issue of asymmetrical flow transferring is a critical process which must be put emphasis on. Then it proposes a method to identify this process, and discuss different solution methods. © 2011 IEEE.

关键词： Electric load flow

来源：评论

学校读者我要写书评

暂无评论

A novel fault locator for power distribution system with neutral non-effectively grounded

A novel fault locator for power distribution system with neu...

引用

2011 International Conference on Advanced power system Automation and Protection, APAP 2011

作者： Shi, Shenxing Dong, Xinzhou State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781424496198

Fault locator for power distribution system with neutral non-effectively grounded should locate phase-to-phase fault and single-phase-to-ground fault respectively. For phase-to-phase fault, the point can be located by power-frequency impedance. However, for single-phase-to-ground fault with limited power-frequency current not more than load current, a novel fault location technology should be developed. The paper will present a practical single-phase-to-ground fault location based on fault generated traveling waves acquired from one phase current transducer and zero sequence current transducer at first. Then implementation of the novel fault locator is proposed including hardware design and software flowchart. At last field tests will be made to verify the feasibility of the fault locator. © 2011 IEEE.

关键词： Transducers

来源：评论

学校读者我要写书评

暂无评论

Estimating the electromechanical oscillation characteristics of power system based on measured ambient data utilizing stochastic subspace method

Estimating the electromechanical oscillation characteristics...

引用

2011 IEEE PES General Meeting: The Electrification of Transportation and the Grid of the Future

作者： Jingmin, Ni Chen, Shen Feng, Liu State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781457710018

Estimating low-frequency oscillation modes and the corresponding mode shapes based on ambient data from WAMS measurements has a promising prospect of application in power system analysis and control. The present approaches estimate the modes and mode shapes respectively, which greatly reduce the computational efficiency. Besides, there is no good solution for the problem of discriminating real modes from the spurious ones caused by numerical error. A method based on stochastic subspace method was proposed in this paper. By choosing the angle measurements of all buses as input signals for the method, the modes and simultaneously the corresponding mode shapes of any bus can be estimated conveniently. By introducing the idea of reference channels, the computation complexity was substantially reduced without decreasing the accuracy. Stabilization diagrams technique was introduced to discriminate the real modes from the spurious ones. The test case based on the IEEE-118 system indicated that the method proposed is satisfying in respect of both computational efficiency and accuracy of results. © 2011 IEEE.

关键词： Computational efficiency

来源：评论

学校读者我要写书评

暂无评论

Analyses on frequency transmission characteristic of traveling wave in distribution power system

Analyses on frequency transmission characteristic of traveli...

引用

2011 International Conference on Advanced power system Automation and Protection, APAP 2011

作者： Wang, Jun Shi, Shenxing Dong, Xinzhou Wang, Bin State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

ISBN: (纸本)9781424496198

Under the skin effect caused by the alternating electromagnetic field, the transmission line parameters changes with frequency, and different line resistivity, surge impedance, wave speed are presented in one line under the different frequency bands of signal. This phenomenon is usually called Frequency transmission characteristic, which is mainly discussed in this paper. This paper first studied the line resistivity, wave speed and surge impedance of zero-mode component and line-mode component in different frequency bands. Then, the line structure and its effection on Frequency transmission characteristic are presented. Last, the frequency transmission characteristic on a certain line fault is discussed based on a typical distribution system model. The research in this paper is meaningful for future study on the fault feeder selection and fault location technology based on traveling wave in the distribution system. © 2011 IEEE.

关键词： Wavelet transforms

来源：评论

学校读者我要写书评

暂无评论

Rule Extraction in Transient Stability Study Using Linear Decision Trees

引用

中国电机工程学报 2011年第34期31卷 I0006-I0006页

作者： SUN Hongbin WANG Kang ZHANG Boming ZHAO Feng State Key Lab of Control and Simulation of Power Systems and Generation Equipments （Dept. of Electrical Engineering Tsinghua University） Haidian District Beijing 100084 China

Traditional operation rules depend on human experience, which are relatively fixed and difficult to fulfill the new demand of the modern power grid. In order to formulate suitable and quickly refreshed operation rules, a method of linear decision tree based on support samples is proposed for rule extraction in this paper. The operation rules extracted by this method have advantages of refinement and intelligence, which helps the dispatching center meet the requirement of smart grid construction.

关键词：英文摘要内容介绍编辑工作期刊

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：