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6th International Conference on Renewable Power Generation

作者： Guopeng, Zhao Qiang, Zhao Jiyun, Ren Xiaofang, Song Minxiao, Han State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing102206 China School of Electrical and Electronic Engineering North China Electric Power University Beijing102206 China State Key Laboratory of Smart Grid Protection and Control Nanjing Jiangsu Province211006 China

With the expending scale of the power grid and the substantial development of renewable energy generation system, the demand for power quality is becoming more and more significant. The doubly fed pumped storage can be an effective method to control the power of the power grid and restrain the power grid fluctuation caused by renewable energy generation. First, this study introduces the structure of doubly fed pumped storage unit, and analyses the mathematical model of reversible hydraulic pump turbine, doubly fed induction generator (DFIG) and control strategy of the converter. On the basis of the model of reversible hydraulic pump turbine and DFIG, control strategies of the dq decoupling and synchronous rotating coordinate system are studied to output the active and reactive power. Second, the models of generating mode and pumping mode for the doubly fed pumped storage unit are established. Third, for the grid power regulation, active power and speed control strategy in generating mode, pumping mode are put forward. Finally, the model of doubly fed pumped storage unit of 300 MW is established in MATLAB/Simulink. The proposed control strategy is verified by the simulation results. © 2017 Institution of Engineering and Technology. All Rights Reserved.

关键词： Renewable energy resources

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Ultra-short-term wind speed forecasting method based on spatial and temporal correlation models

Ultra-short-term wind speed forecasting method based on spat...

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6th International Conference on Renewable Power Generation

作者： Zhou, Haiqiang Xue, Yusheng Guo, Jizhu Chen, Jiehui Energy and Electrical Engineering School Hohai University Nanjing Jiangsu Province211100 China NARI Group Corporation State Grid Electric Power Research Institute Nanjing211106 China State Key Laboratory of Smart Grid Protection and Control Nanjing211106 China

An ultra-short-term wind speed forecasting method based on spatial and temporal correlation models is proposed. Firstly, the temporal correlation model was studied. The generalised distance of wind speed time series is defined based on the dynamic time warping distance and correlation coefficient. Samples with similar wind dynamic patterns are classed into the same group. Time series in one group are depicted with a representative time series which is modelled by an autoregressive moving average (ARMA) model. For time series which cannot be classed to any of these groups, a special group was defined. It was modelled by artificial neural network (ANN). Secondly, the spatial correlation between the target wind farm and the reference wind farm was investigated with the meteorological data taking into consideration. The grey prediction method is utilised to predict the wind speed. Finally, the combined ultra-short-term wind speed forecasting method is proposed. It takes into account the inherent time correlation of the target wind speed and its spatial correlation with reference wind farm. The wind speed prediction of wind farms in northwest USA verifies the effectiveness and feasibility of the proposed method. © 2017 Institution of Engineering and Technology. All rights reserved.

关键词： Time series

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Realization of a Master-slave Mode Co-simulation in Cyber Physical system Based on Hybrid Time Synchronization Strategy

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Dianli Xitong Zidonghua/Automation of Electric Power systems 2017年第10期41卷 9-15and91页

作者： Zhou, Li Wu, Zaijun Sun, Jun Su, Chen Gu, Wei Shi, Yuxiang School of Electrical Engineering Southeast University Nanjing210096 China NARI Group Corporation State Grid Electric Power Research Institute Nanjing211106 China State Key Laboratory of Smart Grid Protection and Control Nanjing211106 China

Along with the deeper coupling between power system and information communication system, such traditional simulation methods as decoupling communication and ideal simulation can hardly satisfy the realistic demand because of the communication faults of time delay, bit error and interruption. Based on an analysis of existing modeling techniques of cyber physical system, a master-slave mode co-simulation platform supported by MATLAB and OPNET is proposed. Some key problems such as the co-simulation framework, the model in MATLAB and OPNET, software-based virtual measuring equipment and interactive interface are expounded, in which a hybrid time synchronization strategy is designed and analyzed. A microgrid case study is given to demonstrate the feasibility and availability of the co-simulation platform. © 2017 Automation of Electric Power systems Press.

关键词： Cyber Physical system

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Research on an improved visual background extraction algorithm

Research on an improved visual background extraction algorit...

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International Conference on Intelligent system and Knowledge Engineering, ISKE

作者： Dandan Lu Ningning Zhou Guofang Huang School of Computer Nanjing University of Posts and Telecommunications Nanjing China State Key Laboratory of Smart Grid Protection and Control Nanjing China

The visual background extraction algorithm (ViBe) uses the first frame of the video as the initial frame to initialize the background model. If the initial frame of the background model has a moving object or the state of the moving object changes (from still to motion or from motion to still) or the update rate of the background model is not synchronized with the background variability, there will be false target which is known as ghost. Aiming at this problem, a discriminant method based on histogram similarity measure of foreground region and neighborhood background region is proposed. The algorithm can detect ghost regions from the moving area. The experimental results show that compared with the traditional algorithm, the improved algorithm can effectively remove the ghost of foreground detection, and the detection of the object is more accurate.

关键词： Histograms Computational modeling Heuristic algorithms Algorithm design and analysis Visualization Object detection High definition video

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Ensemble learning for image recognition

Ensemble learning for image recognition

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International Conference on Intelligent system and Knowledge Engineering, ISKE

作者： Xu Chen Long Hong Guofang Huang School of Computer Nanjing University of Posts and Telecommunications Nanjing China State Key Laboratory of Smart Grid Protection and Control Nanjing China

With the continuous development of the Internet and information technology, data has penetrated into every area of today's industry and business functions. Now, data has been already one of the most valuable assets in the Internet and a core element of a company's competitiveness. There seems to have endless data on the Internet, then most of it cannot create value. When we face data mining, wo need to complete a lot of data cleaning tasks. Nowadays, the rapid development of machine learning, especially the deep of learning, has made excellent achievements in natural language processing and image recognition. The paper combines multiple strong learning machine to complete the data learning tasks and image recognition based on ensemble learning, thereby reduce the pressure on the server storage and investment of resource.

关键词： Convolution Kernel Image recognition Feature extraction Biological neural networks Internet

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Study on target tracking algorithm integrating color and contour features

Study on target tracking algorithm integrating color and con...

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International Conference on Intelligent system and Knowledge Engineering, ISKE

作者： Baoying Chen Ningning Zhou Guofang Huang School of Computer Nanjing University of Posts and Telecommunications Nanjing China State Key Laboratory of Smart Grid Protection and Control Nanjing China

Aiming at the instability of traditional color feature tracking algorithm in some complex scenes, an object tracking algorithm with integrating color and contour features is proposed. The algorithm still uses the traditional particle filter to predict the target, but in iteration every time, when searching the best position of the target, the color and contour information of the target can be adaptively combined. Experiments show that it shows good effectiveness and robustness compared with the traditional algorithms when the target is interfered between similar colors or the target is partially obscured.

关键词： Target tracking Image color analysis Histograms Particle filters Shape Interference Prediction algorithms

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A review of stability control technologies for power systems in China

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IOP Conference Series: Earth and Environmental Science 2019年第3期227卷

作者： Jianbo Luo Xijian Dong Feng Xue Yanhong Wei Bijun Li Jie Pan Xiaodan Cui Nan Liu NARI Group Corporation(State Grid Electric Power Research Institute) Nanjing 211106 China State Key Laboratory of Smart Grid Protection and Operation Nanjing 211106 China Guizhou Jinzhou Electric Power Co. Ltd Jinzhou 562400 China State Grid Shanxi Electric Power Company Taiyuan 030001 China State Grid Baoding Electric Power Supply Company Baoding 071027 China

During the transitional period of UHV network construction, the power grid's characteristics of 'Strong DC and Weak AC' are prominent. Moreover, the high penetration of renewable energies has made the characteristics of power systems profoundly changed facing high operation risks. The security and stability control technologies need to be reviewed considering current development situations and combine the characteristics of the grid to make innovation. This paper analyses the development and status quo of stability control technologies from the security and stability control systems which belong to the second defense line. Moreover, frequency and voltage emergency control devices and out-of-step separation devices which belong to the third defense line, as well as features of the security and stability control devices are investigated. According to the planning and development of the future power grid, the development directions of the security control technology is pointed out.

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High-accurate estimation method of sub-synchronous and super-synchronous harmonic parameters on PMU

High-accurate estimation method of sub-synchronous and super...

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6th International Conference on Renewable Power Generation

作者： Tan, Yong Chen, Rong Wang, Meng Zhang, Min Hou, Mingguo NARI Group Corporation State Grid Electric Power Research Institute Nanjing21106 China NARI Technology Development Co. Ltd. Nanjing211061 China State Key Laboratory of Smart Grid Protection and Control Nanjing210061 China School of Rail Transportation Soochow University Suzhou215131 China

With the rapid development of renewable energy power generations, AC/DC transmissions and static compensations etc., power electronic technology has been widely applied in power system. As traditional power equipment is replaced by a large number of power electronic devices, the disturbances such as harmonic interference and sub-synchronous oscillation are more frequently. In order to detect the subsynchronous oscillation in power system in time, and take measures to ensure the safety and stability of power system, this article analyses the algorithm principle of the phasor measurement unit (PMU) and the communication architecture of wide area measurement system (WAMS)/ PMU system. According to the IEEE Std C37.118-2011 standard, it elaborates the problems and the limitations existing in the monitoring of sub-synchronous and super-synchronous harmonic parameters on WAMS. On the basis of the above, a method of online identification and alarm for the sub-synchronous and super-synchronous harmonic parameters on PMU device is proposed. Combined with the fast Fourier transform spectrum correction theory, the high-accuracy identification method of distributed sub-synchronous and super-synchronous harmonic parameter is realised. The feasibility and accuracy of the method is verified by simulation experiments. © 2017 Institution of Engineering and Technology. All Rights Reserved.

关键词： Fast Fourier transforms

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Frequency Characteristic of New-type Load Considering Power Electronics Technology

Frequency Characteristic of New-type Load Considering Power ...

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IEEE International Conference on Cyber Technology in Automation, control, and Intelligent systems

作者： Qian Chen Meng Jiang Ping Ju Xin Shan Bo Wang Yi Wang Fangzhao Yu Lin Xu Chuan Qin College of Energy and Electrical Engineering Hohai University Nanjing China NARI Group Corporation State Key Laboratory of Smart Grid Protection and Control Nanjing China

ISBN: (纸本)9781538604915

Power electronics based load equipment has now more and more used in power grid these years. Their frequency characteristic is worthy of study in detail for it is very different from that of traditional load equipment, and the regular load model may not be suitable such as in the security and stability analysis of modern power system. Firstly, so much these new-type load equipment are classified in several typical categories. Then, response curves are obtained from physical experiment. Thereafter, the static frequency characteristic of new-type loads is discussed and the trend of parameters is predicted. Finally, compared with the recording curves of a real bulk power grid during large frequency disturbs, the change of parameter is verified and the potential impact on power grid is analyzed.

关键词： Power grids Reactive power Motor drives Power system stability Switches Power supplies Load modeling

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Research on the grabcut image segmentation method based on superpixel

Research on the grabcut image segmentation method based on s...

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International Conference on Intelligent system and Knowledge Engineering, ISKE

作者： Yang Liu Ningning Zhou Guofang Huang School of Computer Nanjing University of Posts and Telecommunications Nanjing China Nanjing University of Posts and Telecommunications Nanjing China State Key Laboratory of Smart Grid Protection and Control Nanjing China

In order to overcome the Excessive time complexity of bad quality when the disposing the picture whose foreground is similar to background of grabcut method, a grabcut method based on superpixel is proposed in this paper. This method, firstly, extracting the superpixel block of the picture. And then, split the picture which is extracted. The experimental results show that this method is effective to improve the speed of segmentation. What's more, this method can solve the problem of bad quality when the disposing the image whose foreground is similar to background in a certain extent. This paper has certain advantage in disposing those image whose size are too big and foreground is similar to background.

关键词： Image segmentation Image color analysis Algorithm design and analysis Clustering algorithms Feature extraction Partitioning algorithms Time complexity

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