检索结果-内蒙古大学图书馆

2011 International Conference on Electrical Machines and systems, ICEMS 2011

作者： Lingyun, Bai Zhengming, Zhao Yi, Lei Shuping, Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China Beijing Command College of CAPF Beijing 100012 China Anhui Electrical Research Institute Hefei 230022 China

ISBN: (纸本)9781457710445

On the basis of analyzing the composition of losses in high-efficient high-voltage asynchronous motors, the approaches of increasing the efficiency of the motors is investigated in this paper. The approaches concern with the improvement of material, winding, fan, magnetic groove and so on. By taking the economy and efficiency into account synthetically, the design of the YKK series induction motors is carried on, and it is realized by software simulation. © 2011 IEEE.

关键词： Induction motors

来源：评论

学校读者我要写书评

暂无评论

A Study on Capacity of Distributed Generation and its Effect on Short Circuit Current at Microgrid Operation Mode

A Study on Capacity of Distributed Generation and its Effect...

引用

2011 4th International Conference on Electric Utility Deregulation and Restructuring and power Technologies(第四届电力设施管制、重建及能源技术国际会议 DRPT 2011)

作者： JIN Qiang ZHANG Shuo LI Yong-li Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin China

Now more and more distributed generations will be connected to distributed power ***'s found that different distributed generation has its own operation characteristic such as fluctuation and *** micro-grid is to be island the voltage and frequency will change,so different control modes have been used on different distributed *** kinds of distributed generation have different behavior when system operates normally or fault *** and equivalence were adopted to deal with all kinds of the distributed generations in *** distributed generations with same control mode can be combined to an equivalent *** system operates on grid-connection mode the short circuit current relies on the capacity of grid so it is rather large for the capacity of distribution grid is much more than that of distributed *** when micro-grid operates on island mode the short circuit current may decrease to a relative small *** current protection is widely used in distribution system,and the performance of it is dependent on operation mode,so the value estimate of short circuit current is necessary for verification of credibility and *** summations of capacity were proposed to estimate the minimum and maximum short-circuit current in island.

关键词： capacity of distributed generation :equivalent capacity:short-circuit current:operation mode:over current protection

来源：评论

学校读者我要写书评

暂无评论

Constant voltage control on DC bus of PV system with flywheel energy storage source (FESS)

Constant voltage control on DC bus of PV system with flywhee...

引用

International Conference on Advanced power system Automation and Protection (APAP)

作者： HuiZhi Zhang YongLi Li Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University 300072 China

Fluctuation of the voltage is always the major barrier to the effective application of photovoltaic energy. In this paper, the flywheel energy storage system (FESS) is added to PV system. Considering the fluctuation of photovoltaic energy and limitation of flywheel capacity, flywheel may store energy from the photovoltaic source or AC system, or release energy to load in order to maintain the stable voltage on DC bus. Five different system operating modes and corresponding control strategies are presented in this paper. Corresponding to the different system operating modes, simulation has been done and the control strategies of FESS have been proved valid.

关键词： Industries

来源：评论

学校读者我要写书评

暂无评论

A Grid-Connection control Scheme of PV system with Fluctuant Reactive Load

A Grid-Connection Control Scheme of PV System with Fluctuant...

引用

2011 4th International Conference on Electric Utility Deregulation and Restructuring and power Technologies(第四届电力设施管制、重建及能源技术国际会议 DRPT 2011)

作者： Bin Li Xiaohe Tian Hongyan Zeng Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin China

The fluctuations of reactive load in micro-grid will have a great impact on the supply *** this paper,a novel grid-connection control is proposed in view of this problem,based on a model of a PV system with load paralleled in large *** can not only make full use of photovoltaic power,but also maintain a stable voltage with a fluctuant reactive *** adopted double-loop principle in inverter *** gridconnected current of the PV system and the current of large system are both decoupled into active and reactive component by abc/dq0 transformation to achieve the independent control of active and reactive *** the one hand,the active component of the PV grid-connected current is adjusted to the reference value given by the Maximum power Point Tracking (MPPT) in order to maintain maximum active power output of PV,the reactive component of the large system current is adjusted in order to maintain a constant reactive power *** a stable supply voltage can be maintained with a fluctuant reactive load,as the supply voltage of the grid-connected PV system is mainly sustained by the large *** the other hand，the main circuit topology of three-phase reactive power compensation device and three-phase grid-connected inverter is exactly the ***,in support of a reasonable control strategy it can be integrated together with both function of grid connection and reactive power compensation *** can ensure a stable voltage in the PV system with a fluctuant reactive load paralleled in large system by the regulation of *** advantages compared with the simple and traditional unitypower-factor inverter control scheme are validated by simulation with Matlab/Simulink.

关键词： component:PV system:control scheme:reactive load:grid-connection

来源：评论

学校读者我要写书评

暂无评论

Analysis of directional pilot protection on transmission line with wind farm integration

Analysis of directional pilot protection on transmission lin...

引用

International Conference on Advanced power system Automation and Protection (APAP)

作者： Bin Li Meng Lin Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University 300072 China

Increased integration of wind power makes higher demands on the stability and protection of power system. Wind farms are connected to power grid through transmission line. When single-phase fault occurs on the line, positive and negative sequence currents are not equal and are much smaller than zero sequence current. Phase selector based on the theory of current- difference sudden-change may mistake single-phase fault for phase-to-phase fault because positive and negative branch coefficients are not equal. Considering a case of mal-operation of directional pilot protection, the paper studies the impedance characteristics of asynchronous wind generator, analyzes the causes of weak feed and different branch coefficients, and explains their contribution to fault phase selector's mal-operation. The results are validated by simulation and an improvement for fault phase selection with wind farm integration is proposed.

关键词： Circuit faults Wind farms Impedance Feeds Wind power generation power transmission lines Generators

来源：评论

学校读者我要写书评

暂无评论

Harmonic Analysis of the Interconnection of Wind Farm

Harmonic Analysis of the Interconnection of Wind Farm

引用

The 2011 International Conference on Electric and Electronics (EEIC 2011)

作者： Jidong Wang Xuhao Du Guodong Li Guanqing Yang Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin Electric Power Science & Research Institute

With the large-scale wind farms accessing systems continuously and a wide range of variable speed wind turbines' application, the harmonic problems caused by the interconnection of wind farms have got more and more attention. This paper analyzes the harmonic mechanism caused by wind farms connected with the grid;based on Dig SILENT / power Factory simulation platform, establishes a permanent magnet direct drive wind turbine model. Finally, the harmonic simulation of an actual example for a wind farm connected with the grid is given in this paper. simulation results show that the second harmonic current of the wind farm accessing point and the third harmonic current of point of common coupling are exceeded, which should be suppressed;the contents of other harmonics are in the allowed range of Chinese National Standard.

关键词： wind farm interconnection harmonic simulation

来源：评论

学校读者我要写书评

暂无评论

Effects of nonlinear gradient index on radiative heat transfer in a one-dimensional medium by the DRESOR method

引用

Journal of Physics: Conference Series 2012年第1期369卷

作者： Z C Wang Q Cheng G H Wang Z F Huang H C Zhou State Key Laboratory of Coal Combustion Huazhong University of Science and Technology Wuhan 430074 Hubei People's Republic of China State Key Laboratory of Control & Simulation of Power System & Generation Equipment Department of Thermal Engineering Tsinghua University Beijing 10084 P. R. China To whom any correspondence should be addressed

The DRESOR (Distribution of Ratios of Energy Scattered by the medium Or Reflected by the boundary surface) method is applied for radiative heat transfer in a one-dimensional medium with a nonlinear gradient index and gray boundary surfaces. In this proposed method, the DRESOR values calculated by the Monte Carlo method express quantitatively the impact of scattering on radiative transfer and the radiative intensity with high directional resolution of high precision can be easily obtained. With given media characteristics and boundary conditions, the temperature and radiative flux distributions inside the medium are calculated under the condition of radiative equilibrium. It is shown, in the cases studied, that the DRESOR method has a good accuracy. The temperature distributions have a node with different kinds of sine changed gradient index distributions under the same boundary emissivity. The impact of the gradient index on the radiative heat transfer is considerable, and the same as that of the ratios of its amplitude and average index. Besides, the effects of optical thickness, boundary emissivity and scattering phase function on radiative transfer also should be paid adequate attention.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A Two-level Energy Storage system for Wind Energy systems

A Two-level Energy Storage System for Wind Energy Systems

引用

2011 International Conference on Energy and Environment(ICEE 2011)

作者： Xi Xiao Hu Yi Qing Kang Jinfeng Nie State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University

Wind power outputs fluctuate with the changing of wind speed. The use of energy storage equipment is considered a reasonable solution to suppress wind power fluctuations. An energy storage mode may have its disadvantages over the others, for example, capacity limits, dynamic response, higher prices or shorter lifetime. Moreover, wind power fluctuations are present at different frequencies, to demand the energy storage to offer power support in different time ranges. To improve the performance, in this paper, a combined energy storage mode is discussed to meet the short-term and longterm energy storage requirement for wind power. Short-term energy storage is designed to meet the fast-changing power, using such as super capacitors. Long-term energy is designed to meet the large-scale capacity requirement using Li-ion battery or Vanadium Redox Battery(VRB). By analyzing the actual data of wind power outputs, the capacities of the two kinds of energy storage means are given as an example of the method.

关键词： wind power energy storage capacity designing

来源：评论

学校读者我要写书评

暂无评论

A predictive DC voltage control scheme for back-to-back converters based on energy balance modeling

A predictive DC voltage control scheme for back-to-back conv...

引用

International Conference on Electrical Machines and systems (ICEMS)

作者： Lu Yin Zhengming Zhao Ting Lu Fanbo He Liqiang Yuan State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

This paper presents a predictive control scheme of DC-link voltage for back-to-back converters based on energy balance modeling. Since the variation of DC-link voltage is affected by the energy mismatch between rectifier and inverter, the energy distribution in a rectifier-inverter is analyzed. Moreover, in order to calculate the input and output energy in one control period accurately, the grid current is regulated by predictive control and the instantaneous active power consumed by the induction motor is estimated. Then, an equation based on energy balance in one control period is established, and the DC-link voltage can be controlled by solving it. Finally, simulation results show that with the proposed control scheme, the back-to-back converter exhibits both good dynamic and steady-state performances.

关键词： Voltage control Induction motors Rectifiers Capacitors Vectors Pulse width modulation Inverters

来源：评论

学校读者我要写书评

暂无评论

A Two-level Energy Storage system for Wind Energy systems

A Two-level Energy Storage System for Wind Energy Systems

引用

2011 International Conference of Environmental Science and Engineering（ICESE 2011）

作者： Xi Xiao Hu Yi Qing Kang Jinfeng Nie State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua University

Wind power outputs fluctuate with the changing of wind speed. The use of energy storage equipment is considered a reasonable solution to suppress wind power fluctuations. An energy storage mode may have its disadvantages over the others, for example, capacity limits, dynamic response, higher prices or shorter lifetime. Moreover, wind power fluctuations are present at different frequencies, to demand the energy storage to offer power support in different time ranges. To improve the performance, in this paper, a combined energy storage mode is discussed to meet the shortterm and long-term energy storage requirement for wind power. Short-term energy storage is designed to meet the fast-changing power, using such as super capacitors. Long-term energy is designed to meet the large-scale capacity requirement using Li-ion battery or Vanadium Redox Battery(VRB). By analyzing the actual data of wind power outputs, the capacities of the two kinds of energy storage means are given as an example of the method.

关键词： Wind power energy storage capacity designing

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：