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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

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CAI combustion comparison between NVO strategy and EGRB strategy

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Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (Engineering and Technology Edition) 2011年第SUPPL. 1期41卷 47-52页

作者： Li, Hua Cheng, Peng Tan, Man-Zhi Gu, Yan-Hua Wang, Hui Peng, Ya-Ping Guo, Ying-Nan State Key Laboratory of Automotive Simulation and Control Jilin University Changchun 130022 China Beijing Polytechnic College Beijing 100042 China System and Function Development Technical Center United Automotive Electronic Systems Co. Ltd. Shanghai 201206 China

On the basis of self-developed electro-hydraulic variable valve train, controlled auto-ignition (CAI) was achieved under two different EGR strategies on a modified single cylinder engine. Stable CAI operating ranges of these two valve timing scenarios were obtained by plotting tested operating points. Within the operating range, engine performances and combustion features were analyzed. The experimental results indicate that operating range of NVO strategy, allowing more substantial adjustment of valve phase, is wider than that of EGRB strategy at fixed engine speed of 1000 r/min. The maximum BMEP of EGRB strategy slightly exceeds the NVO strategy. Moreover, brake thermal efficiency exceeds 30% in most of these two operating range, higher than conventional engine, with an extremely low NOx emission at the same time. Besides, start of combustion of CAI under NVO strategy is a little advanced and combustion duration is a little shorter compare with that of EGRB strategy.

关键词： Ignition

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Application of back propagation neural network to fault diagnosis of direct-drive wind turbine

Application of back propagation neural network to fault diag...

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

作者： An, Xueli Jiang, Dongxiang Li, Shaohua State Key Laboratory of Control and Simulation of Power System and Generation Equipments Dept. of Thermal Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9781424489213

The vibration signals of wind turbines are highly nonlinear and non-stationary due to wind turbine operation conditions that are very complicated. The signals will be more complex when a fault occurs. Aiming at these problems, a fault diagnosis method for direct-drive wind turbine is presented based on back propagation neural network (BPNN). The time-domain feature parameters of vibration signals in the horizontal and vertical direction are considered in the method. Five experiments of direct-drive wind turbine with normal, wind wheel mass imbalance, wind wheel aerodynamic imbalance, yaw and blade break are carried out in laboratory scale. Through analyzing the features of five conditions, the time-domain feature parameters in horizontal and vertical direction of the vibration signal are selected as the input samples of BPNN. By training, the BPNN model can be constructed between feature parameters and fault types. The validity of the BPNN model is verified using test samples. The results indicate that the proposed method has higher diagnostic accuracy. It can used in on-line fault diagnosis of direct-drive wind turbines. © 2010 IEEE.

关键词： Failure analysis

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Discussion on setting calculation of loss-of-excitation protection for large turbogenerator

Discussion on setting calculation of loss-of-excitation prot...

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作者： Yao, Siwang Wang, Weijian Luo, Ling Gui, Lin Qiu, Arui State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9788986510119

Loss of excitation (LOE) is a common fault found in the generators. The most widely applied method for detecting a generator loss of excitation is the use of impedance relays to sense the variation of impedance as viewed from the generator terminals [1]. However, compared with China's approachs, in the setting of impedance circle, the IEEE's allow the circle to extend along the negative X axis, meanwhile, in the latest edition of the "IEEE Guide for AC Generator Protection", the circle is further extended, reaching to -*** think this is adverse, to prove our point, the paper ,basing on the IEEE 9 bus model and using computer digital simulation, have studied various loss-of-excitation conditions and some system disturbances that may lead to the relay false tripping. simulation results indicate that the IEEE's method not only can't accelerate the operation effectively, but also will increase the chances of maloperation.

关键词： Electric equipment protection

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Capacity credit evaluation of wind power with sequential Monte Carlo method

Capacity credit evaluation of wind power with sequential Mon...

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2010 International Conference on E-Product E-Service and E-Entertainment, ICEEE2010

作者： Kong, Xiangyu Cui, Kai Jia, Hongjie Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin China State Power Economic Research Institute Beijing China

ISBN: (纸本)9781424471614

Wind can be considered as an interesting alternative to fossil fuels, but as a power source, is both intermittent and diffuse. It is necessary to calculate wind equivalent capacities in order to introduce a coherent evaluation of wind production in the management of the centralized production park. Base on the sequential Monte Carlo simulation technique for wind speeds, an auto-regressive and moving average time series model was used to simulate wind power. And a capacity credit evaluation of wind power method was proposed, which provides the existence probability of wind generation possible outage capacity levels. A number of sensitivity analyses were presented with case studies to illustrate possible applications of the proposed method. ©2010 IEEE.

关键词： Wind power

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Analysis on the negative sequence impedance directional protection for stator internal fault of turbo generator

Analysis on the negative sequence impedance directional prot...

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作者： Hao, Liangliang Sun, Yuguang Arui, Qiu State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

ISBN: (纸本)9788986510119

In order to protect more turn-to-turn faults for the turbo-generator with only three lead-out terminals in the neutral side, this paper applies a new principle protection - negative sequence impedance directional protection of fault components for stator internal asymmetrical fault. By means of Multi-loop Method, all possible internal short-circuit faults and single branch shutdown faults of a 300MW turbo-generator are calculated to obtain the protection performance. Calculation and performance analysis show that, this new principle protection is superior to other existing protections in the aspect of sensitivity and protection range, especially for interturn faults of turbogenerator stator winding. In addition, it won't incorrectly trip on external faults. Thus, this new principle protection can provide safeguard of high quality for internal faults in turbo-generator with only three lead-out terminals in the neutral side.

关键词： Stators

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

Design and implementation of the high efficiency photovoltai...

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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

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Application of automatic differentiation technique to the transient simulation of distributed generation system

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Dianli Xitong Zidonghua/Automation of Electric Power systems 2010年第23期34卷 71-75+101页

作者： Wang, Chengshan Huang, Bibin Li, Peng Gao, Fei Ding, Fei Ding, Chengdi Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China

In view of the diversity of the distributed generation control system and the influence on the simulation efficiency due to adoption of the user-defined model based on the basic elements of control systems, a control system compositional modeling method is proposed that consists in combining the basic elements into a number of functions. The corresponding compositional function values and derivatives can be accurately and highly efficiently found using the automatic differentiation technique, effectively increasing the computational efficiency of the simulation program while maintaining the code maintainability and scalability. This method is validated with an example. © State Grid Electric Power Research Institute Press.

关键词： Distributed power generation

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Reactive power compensation devices optimization based on improved ant colony algorithm

Reactive power compensation devices optimization based on im...

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International Conference on Electrical and control Engineering, ICECE 2010

作者： Jiang, Huilan He, Ming Liu, Lin Ji, Huiqiang Shan, Dapeng Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China Tianjin High Voltage Power Supplied Company Tianjin 300250 China

ISBN: (纸本)9780769540313

In the assumption that all load nodes are installed reactive power compensation device, injecting a variety of disturbances to the grid, through the application of improved ant colony algorithm, we can obtain the optimal control sequence under disturbance, that is current switching reactive power compensation device node location. Comparing control sequences under the various perturbations, with circulation mechanism of successive exclusion, the best installation location of reactive power compensation devices is obtain, while the system voltage deviation smaller, improving power system operation economy. In this paper, there is a planning example, the results show that the proposed method is feasible. © 2010 IEEE.

关键词： Electric power utilization

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An improved under frequency load shedding scheme based on rate of change of frequency

An improved under frequency load shedding scheme based on ra...

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International Conference on Electrical and control Engineering, ICECE 2010

作者： Jiang, Huilan Yan, Geng Ji, Huiqiang Liu, Lin Shan, Dapeng Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China Tianjin High Voltage Power Supplied Company Tianjin 300250 China

ISBN: (纸本)9780769540313

In allusion to the traditional UFLS scheme's deficiencies of changeless frequency setting value and amount of load shedding of every run, this paper proposes improved UFLS scheme which can alter the frequency setting value of the first run and the amount of load shedding of every run dynamically according to the magnitude of frequency change rate, namely the insufficient amount of active power. The simulation results of stand-alone model show that the reformative UFLS scheme can restrain the frequency falling depth effectively, fit speed controller preferably, make full use of system rotating spare capacity, and reduce the amount of load shedding and the possibility of over-cut or owes-cut. © 2010 IEEE.

关键词： Electric load shedding

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