检索结果-内蒙古大学图书馆

International Conference on Renewable power Generation (RPG 2015)

作者： Kangping Li Fei Wang Zhao Zhen Yujing Sun Zengqiang Mi Hongbin Sun Chun Liu Bo Wang Jing Lu State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources (North China Electric Power University) Baoding 071003 Hebei Province China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment (Department of Electrical Engineering Tsinghua University) Haidian District Beijing 100084 China China Electric Power Research Institute Haidian District Beijing 100192 China)

ISBN: (纸本)9781510821415

Operating Statuses Identification (OSI) can help operators to find fault timely and minimize the loss. So it is of great significance for optimal operation of photovoltaic (PV) plants. The loss quantity of electricity (LQOE) is defined as that should have been generated but actually not, which is caused by inverter fault, PV modules fault, dust stratification or combinations of them. Firstly, mathematical models of PV cells are proposed to figure out the LQOE of each PV module. Secondly, after analysing the relation between LQOE and operating statuses, an index set of LQOE describing the distinction of different operating statuses are defined including four statistical feature parameters and a user-defined index. Thirdly, Support Vector Classification models for OSI (OSI-SVC) are built with input features extracted from the index set. Lastly, simulations are carried out to verify the effectiveness and evaluate the performance of the OSI-SVC models. The results indicated that the operating statuses can be effectively recognized by the proposed model.

关键词： Feature Extraction Loss quantity of electricity Operating Statuses Identification Support Vector Machine

来源：评论

学校读者我要写书评

暂无评论

Cloud identification model for sky images based on Otsu

Cloud identification model for sky images based on Otsu

引用

International Conference on Renewable power Generation (RPG 2015)

作者： Hongping Li Fei Wang Hui Ren Hongbin Sun Chun Liu Bo Wang Jing Lu Zhao Zhen Xiaoli Liu State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources (North China Electric Power University) Baoding 071003 Hebei Province China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment (Department of Electrical Engineering Tsinghua University) Haidian District Beijing 100084 China China ElectricPowerResearch Institute HaidianDistrict Beijing 100192 China

Irradiance changes caused by clouds movement are the main factors, which lead to mutation of photovoltaic power. In order to increase the accuracy of the ultra-short-term photovoltaic power prediction, based on of clouds images, the cloud identification for sky images is one of the primary aspects for improving photovoltaic power accuracy. A cloud identification model for sky images is established based on Otsu. Firstly, a series of sky images are collected by Total Sky Imager (TSI) with the regions of clouds and sky are distinguished. Secondly, the color features (based on RGB values) of pixels in sample images and the spectral and texture features of the whole image are extracted; Finally, we established a cloud identification model for sky images based on Otsu according to the clouds' and sky areas' division and the general characteristics featured by pixels and images. The simulated results show that the model in this paper can identify the clouds in a sky images effectively.

关键词： Otsu cloud identification texture threshold Clouds sky images texture textures pixel

来源：评论

学校读者我要写书评

暂无评论

Fault transient simulation analysis for HVDC transmission lines

Fault transient simulation analysis for HVDC transmission li...

引用

International Conference on Electric Utility Deregulation and Restructuring and power Technologies (DRPT)

作者： Luhua Xing Dong Yang Dandan Zhang Wenbo Li Qing Chen State Grid Shandong Electric Power Research Institute Jinan China Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan China

Fault transient analysis plays an important role in protection and fault location research for high voltage direct current (HVDC) transmission lines. Fault transient simulation methods and analysis for HVDC transmission lines are detailed presented in this paper, to avoid repetitive tasks and waste of research efforts. Influences of the control system, operation modes and direct current (DC) filter links on the fault transient simulation analysis for HVDC transmission lines are discussed. Transient characteristics of voltages and currents on HVDC transmission lines for faults on HVDC transmission lines, lightning strokes and commutation failures are analyzed, and corresponding simulation methods are also given.

关键词： Lightning Transient analysis power industry Bidirectional control Resistance Decision support systems

来源：评论

学校读者我要写书评

暂无评论

Advanced control strategy of SVC based on artificial immune algorithm

引用

Journal of Computational Information systems 2015年第6期11卷 1965-1972页

作者： Chen, Saisai Li, Kejun Jing, Ping Zha, Guoliang Tian, Xin Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan China Smart Grid Research Institute of State-Grid Changping District Beijing China

For the conventional Static Var Compensator (SVC), there is a contradiction between the response time and system stability. An advanced control strategy is proposed in this paper. Improved Proportional Integral (PI) controller and Artificial Immune Algorithm are adopted in SVC control system, with the response speed of SVC as objective function of optimization. Meanwhile, a non-linear link is added to ensure the stability of the system. The non-linear link is proved that it can significantly improve the stability of the nonlinear system. simulation results show that the new SVC control strategy can not only track the set voltage value of SVC quickly, but also comprehensively compensate for reactive power and three-phase imbalance. Copyright © 2015 Binary Information Press.

关键词： Static Var compensators

来源：评论

学校读者我要写书评

暂无评论

The Fitting Method of Wind power Forecast Error under power-time Dimension

The Fitting Method of Wind Power Forecast Error under Power-...

引用

International Conference on Electric Utility Deregulation and Restructuring and power Technologies

作者： Zhaoqing Wang Chengfu Wang Jun Liang Xueli Wang Libin Yang Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Jinan China State Grid Shandong Electric Power Maintenance Company Jinan China State Grid Qinghai Electric Power institute Xining China

ISBN: (纸本)9781467371070

Randomness and volatility are the inherent attributes of wind power, and the present method for forecasting wind power is not accurate enough. However, the exact description of forecast error has obvious effect on optimized scheme of power flow calculation, unit commitment and operation in the power system with wind power. The wind forecast error is different under the power dimension and correlative under time dimension, so it can describe the actual wind power attributes more accurately on the basis of fitting the forecast error divided into different groups according to the power-time attributes. The parameters distribution like normal distribution can not describe the error in different bins accurately, but this paper proposed non-parameter kernel density estimation (NKDE) to fit the error data in various bins, which is also suitable for various forecast methods. If ignoring the characteristic of NKDE, it has poor fitting effect because of too many bins and too few data in some bins. This paper proposed a method to reduce the number of bins to improve the fitting effect and reduce calculation time. Results for this case show the proposed probability density function (pdf) is more close to the actual wind power error distribution.

关键词： error analysis fitting effect power-time dimension correlation

来源：评论

学校读者我要写书评

暂无评论

Wind power forecasting based on a Markov chain model of variation

Wind power forecasting based on a Markov chain model of vari...

引用

International Conference on Fuzzy systems and Knowledge Discovery (FSKD)

作者： Jingwen Sun Zhihao Yun Jun Liang Ying Feng Tianbao Zhang Key Laboratory of Power System Intelligent Dispatch and Control Shandong University Jinan China Economic & Technology Research Institute State Grid Shandong Electric Power Company Jinan China

In order to provide more decision-making information and improve the effects of probabilistic forecasting, a novel wind power probabilistic forecasting approach based on Markov chain model of variation is proposed in this paper. The transition probabilities matrix of Markov chain model is built from the variations of historical wind power data to compute probability distributions and deterministic wind generation at future moments. Refined state space is built because the value of variation is much smaller than wind generation, which could improve the prediction accuracy. The effectiveness and higher accuracy of proposed approach are proved by actual data from wind farm.

关键词： Wind power generation Markov processes Forecasting Predictive models Probabilistic logic Wind forecasting Wind farms

来源：评论

学校读者我要写书评

暂无评论

Analysis on single-phase line break fault of 10kV non-grounded distribution network

Analysis on single-phase line break fault of 10kV non-ground...

引用

International Conference on Electric Utility Deregulation and Restructuring and power Technologies (DRPT)

作者： Rui Wang Wei Cong Qibao Kang Guoqiang Liu Hui Wang Ruipeng Yi Key Laboratory of Power System Intelligent Dispatch and Control Shandong University Jinan Shandong Province China Binzhou Power Company State Grid Shandong Corporation Binzhou Shandong Province

ISBN: (纸本)9781467371070

Line break fault is becoming more and more frequent in 10kV neutral point non-grounded distribution system. This paper takes 10kV distribution line single-phase line break fault as the research object, analyzes the characteristics of electrical quantities when single-phase line break fault occurs, including single-phase line break without grounding point, single-phase line break with grounding at power supply side and single-phase line break with grounding at load side. Electrical quantities during single-phase line break fault are analyzed using symmetrical component method with sequence network and vector diagram, the variation of electrical quantities are summarized, and protection criterion for single-phase line break fault is proposed. simulation results by PSCAD/EMTDC ensure the correctness of the analysis results and line break protection criterion.

关键词： Grounding Decision support systems power supplies Impedance power industry simulation Analytical models

来源：评论

学校读者我要写书评

暂无评论

Reducing the impact of source internal resistance by source coil in resonant wireless power transfer

Reducing the impact of source internal resistance by source ...

引用

作者： Zhang, Yiming Lu, Ting Zhao, Zhengming State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781479956982

Wireless power transfer (WPT) is the state-of-the-art research interest. In the WPT system efficiency is an important figure of merit. In order to reduce the impact of the source internal resistance and improve the system efficiency of the conventional two-coil structure, a source coil is added to the two-coil structure, forming a three-coil structure. Both the two-coil structure and the three-coil structure are modeled and analyzed with the circuit theory. The system efficiencies of both structures with optimal loads and a fixed load are deduced. The system efficiency of the three-coil structure is proved to be higher than that of the two-coil structure. An experimental apparatus is implemented and the experimental results match well with the theoretical calculations. The larger the source internal resistance, the more significantly the addition of the source coil improves the system efficiency. © 2014 IEEE.

关键词： Energy transfer

来源：评论

学校读者我要写书评

暂无评论

Phase-shift control of isolated bidirectional DC-DC converters for unidirectional power flow

Phase-shift control of isolated bidirectional DC-DC converte...

引用

作者： Ge, Junjie Zhao, Zhengming Ma, Junchao He, Fanbo Yuan, Liqiang Lu, Ting State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781479956982

In the conventional phase-shift control of isolated bidirectional DC-DC converters, the phenomenon of power backflow is quite obvious. General improved phase-shift control methods can reduce the power backflow of the input. However, they do not take the power backflow of the output into consideration. In this paper, a novel phase-shift control of isolated bidirectional DC-DC converters for unidirectional power flow is proposed. It can eliminate the power backflows of both the input and the output at the same time. Furthermore, the converters in the proposed phase-shift control can achieve the zero-current switching in the whole power rang. Experimental results from a prototype verify the feasibility and validity of the proposed control method, and show superior performance. © 2014 IEEE.

关键词： Zero current switching

来源：评论

学校读者我要写书评

暂无评论

Electrical properties of oil-paper insulation affected by water conductivity during paper-making process

Electrical properties of oil-paper insulation affected by wa...

引用

32nd Electrical Insulation Conference, EIC 2014

作者： Huang, Jianwen Zhou, Yuanxiang Jin, Fubao Sha, Yanchao Zhang, Ling Le, Trung Hieu 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)9781479927876

Developments of ultra-high voltage grid in China require better insulation materials, and that forces the transformer presspaper and pressboard manufactures to pay more attention to the papermaking process to enhance their product qualities. In this study, pure water and three kinds of sodium chloride solutions with conductivities of 100 μS/cm, 500 μS/cm and 1000 μS/cm were respectively used to prepare presspaper samples. By vacuum impregnation, four kinds of oil-paper samples were acquired. Test results showed that relative permittivity and tand of oil-paper specimens first varied little then increased a lot with the increasing of water conductivity;DC breakdown field decreased while AC breakdown field changed little. To confirm the differences were due to water conductivity, ion chromatography was used to determine the sodium and chloride ion contents of the presspaper samples, we found that the ion contents increased with electrical conductivity. This indicates that water conductivity does have effects on most electrical properties of oil-paper insulation and lower conductivity can bring better insulation performances. © 2014 IEEE.

关键词： Ion chromatography

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：