检索结果-内蒙古大学图书馆

Fault diagnosis of direct-drive wind turbine based on support vector machine

Journal of Physics: Conference Series 2011年第1期305卷

作者： X L An D X Jiang S H Li J Chen State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing 100084 China

A fault diagnosis method of direct-drive wind turbine based on support vector machine (SVM) and feature selection is presented. The time-domain feature parameters of main shaft vibration signal in the horizontal and vertical directions are considered in the method. Firstly, in laboratory scale five experiments of direct-drive wind turbine with normal condition, wind wheel mass imbalance fault, wind wheel aerodynamic imbalance fault, yaw fault and blade airfoil change fault are carried out. The features of five experiments are analyzed. Secondly, the sensitive time-domain feature parameters in the horizontal and vertical directions of vibration signal in the five conditions are selected and used as feature samples. By training, the mapping relation between feature parameters and fault types are established in SVM model. Finally, the performance of the proposed method is verified through experimental data. The results show that the proposed method is effective in identifying the fault of wind turbine. It has good classification ability and robustness to diagnose the fault of direct-drive wind turbine.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Transient interaction of HVAC and HVDC in converterer station in HVDC, I: Electromagnetic transient model of equipments in DC side

引用

Gaodianya Jishu/High Voltage Engineering 2011年第2期37卷 395-403页

作者： Chen, Shui-Ming Yu, Zhan-Qing Xie, Hai-Bin Huang, Lu-Lu State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

Huge interconnected power grids are formed in AC and DC power systems in China. The nanoseconds, microseconds, milliseconds electromagnetic transient due to AC and DC system operation and fault, the DC converter valve movement, the load generated by changes interact in the AC and DC interconnected system, impairing AC and DC power systems, especially leading to the commutation of DC system failures and atresia such serious incidents. Consequently, a theoretical analysis was combined with a test method to establish an over ground network, considering DC electrical networks, control systems and underground grounding system of the full-wave process of the UHV system, Finally, converter transformer was modeled with UMEC model, and transmission line was modeled with J-Marti frequency dependent model;moreover, valve was modeled with transistor, RLC circuit, and other units including DC controller, and DC filter and AC filter were modeled with RLC circuit. The broadband characteristics of electromagnetic transient models of key units in DC sides for the analysis of AC and DC interconnected system were also analyzed.

关键词： controllers

来源：评论

学校读者我要写书评

暂无评论

Transient interaction of HVAC and HVDC in converter station in HVDC, IV: Effects of DC sides on AC sides

引用

Gaodianya Jishu/High Voltage Engineering 2011年第7期37卷 1590-1597页

作者： Chen, Shui-Ming Yu, Zhan-Qing Huang, Lu-Lu Xie, Hai-Bin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

China AC-DC power systems are interconnected to form a huge power grid. The nanoseconds, microseconds, milliseconds electromagnetic transient were generated due to AC-DC system operation and fault, the DC converter valve movement, the load generated by changes in the interaction of AC-DC interconnected system electromagnetic transient, which can pose a hazard on AC and DC power systems, in particular, can lead to the commutation of DC system failures and atresia such serious incidents. Based on the broadband characteristics model which can accurately reflect the existing AC-DC interconnected system electromagnetic transient characteristics of the key components, we applied the PSCAD/EMTDC platform to establish a computational model, and revealed DC side electromagnetic transient interaction on AC side. The results show that the DC system has little effect on AC system electromagnetic transient, In various types of failures, the overvoltage produced at side of 750 kV, 330 kV lines and bus are in the allowable range.

关键词： HVDC power transmission

来源：评论

学校读者我要写书评

暂无评论

Nonlinear dynamic characteristic analysis of a vertical mass unbalanced rotor

Nonlinear dynamic characteristic analysis of a vertical mass...

引用

23rd International Congress on Condition Monitoring and Diagnostic Engineering Management, COMADEM 2010

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

ISBN: (纸本)9784883254194

The dynamic properties between torsional and bending vibrations of a vertical mass unbalanced rotor are described. The equation of rotor system motion is obtained by Lagrangian dynamics without considering the external actuating forces and torque, shows coupling effect and nonlinear interaction between the rotor system bending and torsional vibrations. An attempt of theoretical analysis and numerical simulation is made to reveal dynamic characteristics of a rotor system. Theoretical analysis of the rotor dynamic equations based on perturbation theory indicates that at stable state of vibration the coupled effect on the rotor system is nonexistent and the bending vibration becomes equal amplitude with shafting speed at stable vibration state. While the torsional vibration keeps on attenuating until it stops. In addition, the numerical simulation results to the dynamic equations, show that coupled torsional and bending vibrations are induced by mass eccentricity, and coupled effect can only be found in vibration initial state of the rotor system. Other numerical simulation results are consistent with the theoretical analysis.

关键词： Perturbation techniques

来源：评论

学校读者我要写书评

暂无评论

Study on lightning protection of cables and transformer in microgrid

Study on lightning protection of cables and transformer in m...

引用

作者： Yu, Hong-Qiao Chen, Shui-Ming Yang, Peng-Cheng State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing 100084 China

ISBN: (纸本)9781457700668

The cable and transformer are important distribution equipment in Microgrid. Due to the low insulation level, the insulation of them is easily damaged by lightning. The models of high-frequency transformer and the calculation model of induced lightning with transmission line based on electromagnetic transient calculation software PSCAD / EMTDC are designed in this paper. The lightning protection of cables and transformer in Microgrid, the transferred overvoltage of transformer and the effect of the length of cables and the load types to overvoltage level are researched. The conclusion shows that the induced overvoltage and transferred overvoltage could be reduced efficiently after installing surge arrester at the cables and transformer, but the direct lightning overvoltage is not reduced in the safety range;The longer the cables, the lower the overvoltage is;The inductively load can reduce the overvoltage level slightly while the capacitive and resistance loads has no influence. © 2010 Chinese Soc for Elec Eng.

关键词： Electrolysis

来源：评论

学校读者我要写书评

暂无评论

Experimental investigation and analysis for gearbox fault

Experimental investigation and analysis for gearbox fault

引用

2010 2nd World Non-Grid-Connected Wind power and Energy Conference, WNWEC 2010

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

ISBN: (纸本)9781424489213

As an important component of a wind turbine drive chain, the high failure rate of the gearbox can have a serious impact on the operation of wind turbine units. The fault diagnosis of the gearbox is therefore important for the safety of wind turbine units. In this paper, a gearbox experiment rig was built, experiments on the gear surface spalling fault were held on the rig under laboratory conditions, the shaft vibration displacement signals were collected, related vibration signals were analyzed by time domain, amplitude domain, frequency domain and wavelet analysis, and the results of different analysis methods were compared. The results show that the waveform of normal and fault signals are similar, the amplitude of the signals will change while the fault happens, and the wavelet analysis is more effective than frequency domain analysis on gearbox fault features extraction. © 2010 IEEE.

关键词： Frequency domain analysis

来源：评论

学校读者我要写书评

暂无评论

A multi-class pattern recognition method for motor imagery EEG data

A multi-class pattern recognition method for motor imagery E...

引用

IEEE International Conference on systems, Man and Cybernetics

作者： Yonghui Fang Minyou Chen Robert F Harrison State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China School of Electronic and Information Engineering Southwest University Chongqing China Department of Automatic Control & Systems Engineering University of Sheffield Sheffield UK

The Common Spatial Patterns (CSP) algorithm is useful for calculating spatial filters for detecting event-related desynchronization (ERD) for use in ERD-based brain-computer interfaces (BCIs). However, basic CSP is a supervised algorithm suited only to two-class discrimination; it is unable to solve multiclass discrimination problems. This paper proposes a new method named the binary common spatial patterns (BCSP) algorithm to extend the basic CSP method to multi-class recognition. Our method arranges the spatial filters and Fisher classifiers in the form of a binary tree whereby N - 1 spatial filters and N - 1 Fisher classifiers are calculated for N class recognition. This is fewer than must be calculated in other methods (e.g. one-versus-rest, OVR). This makes the overall classification procedure less redundant. simulation results show that BCSP has better performance than the OVR scheme and outperforms the three best teams in the 2008 BCI-competition.

关键词： Spatial filters Arrays Feature extraction Electroencephalography Band pass filters Covariance matrix Filtering algorithms

来源：评论

学校读者我要写书评

暂无评论

Design and implementation of the high efficiency photovoltaic system with solid state lighting

Design and implementation of the high efficiency photovoltai...

引用

作者： Hu, Xianlai Yuan, Liqiang Chen, Jian Zhao, Zhengming 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)9788986510119

Photovoltaic application of LED lighting has been a hot trend in residential illumination, for it integrates the advantages of both the PV systems and LED lights. However, it has a series of problems, such as high thermal loss, poor reliability, and a short life span. To address these problems, this paper presents a deep research on the whole system from a low-cost, high-efficiency and long-life point of view. A main circuit integrating maximum power point tracing (MPPT) control and battery management, as well as a double-loop control for LED load is developed. A set of protection system is applied to ensure high reliability of the system. The control strategies are tested on the demonstrator and prove to be effective.

关键词： Integrating circuits

来源：评论

学校读者我要写书评

暂无评论

Crack Growth Prediction of the Steam Turbine Generator Shaft

引用

Journal of Physics: Conference Series 2011年第1期305卷

作者： Dongxiang Jiang Chao Liu 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

The power network in China is encountering great changes and large-scale network is increasingly implemented for long distance power transmission as well as various kinds of power electronic devices, which bring in the risk of the torsional vibration of the turbine generator shafts, may cause the fatigue damage and cracks in the product life cycle. The paper analyzed the failed coupling of some 600MW steam turbine generator and calculated the local stress of the assembly under torsional load caused by the network disturbance. Then the crack propagation was analyzed with the predicted crack initiation position and crack propagation routine. The assembled coupling contains shaft, coupling and keys with interferences between the parts. Therefore the contact analysis was included. Extended Finite Element Method (X-FEM) is used to calculate the crack propagation and that the mesh needs not to be regenerated with the crack propagation, which is beneficial for engineering applications.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Study on stress and strain for fatigue cumulation evaluation in turbine generator shafts due to torsional vibration

Study on stress and strain for fatigue cumulation evaluation...

引用

23rd International Congress on Condition Monitoring and Diagnostic Engineering Management, COMADEM 2010

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

ISBN: (纸本)9784883254194

The cracks emerged in a fossil-fired power plant in China in 2008 and several similar crack accidents had been detected in nuclear turbines in USA before. The possible causes of the cracks are analyzed in previous study while the torsional vibration is one of the most significant factors. The paper analyzes the impact of torsional vibration using the practical running data in some turbine generator unit. Based on the transient response analysis under emulational subsynchronous oscillation model simplified from the practical network, the torques acted on the coupling section are analyzed. Then the stress and strain field is calculated for local dangerous point search in Zone of Vulnerability (ZoV) and the fatigue damage criterion determination. Manson-Coffin equation is used to ascertain whether it is high-cycle fatigue or low-cycle fatigue and the fatigue data from standard test specimen is used. The method using local stress and strain analysis as well as fatigue damage cumulation study may establish a novel way to diagnose the crack in an early stage.

关键词： Transient analysis

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：