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Response to Comments by Yuan WANG on “Trends of Extreme Precipitation in Eastern China and Their Possible Causes”

Advances in Atmospheric Sciences 2015年第10期32卷 1447-1448页

作者： LIU Run LIU Shaw Chen Ralph J.CICERONE SHIU Chein-Jung LI Jun WANG Jingli ZHANG Yuanhang State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking University Research Center for Environmental Changes Academia Sinica Department of Atmospheric Science NCU National Academy of Sciences Earth System Science University of California Institute of Urban Meteorology of China Meteorological Administration

In his comments, Wang cites a number of works to dispute the conclusion in our previous work, which attributes the observed decreases/increases in light/heavy precipitation in eastern China primarily to global warming rather than the regional aerosol effect. However, most of the cited works （admittedly, including our previous work）, employ correlation analysis, which has little bearing on the cause--effect relationship. Theoretical analyses and/or modeling studies are needed to ascertain the cause-effect relationship. We argue that theoretical analyses and modeling results show that global warming is the primary cause of the widely observed phenomena of suppression of light precipitation and enhancement of heavy precipitation across the globe, including in eastern China.

关键词： extreme precipitation global warming aerosols

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A novel control strategy based on multi-agent for wind farm power dispatching

A novel control strategy based on multi-agent for wind farm ...

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International Conference on Renewable power Generation, RPG 2015

作者： Xiao, Yunqi Zhang, Xiaohang Chen, Minna State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing102206 China School of Control and Computer Engineering North China Electric Power University China

ISBN: (纸本)9781785610400

Nowadays, active power reference of wind farm from power grid dispatch center should be allocated to wind turbines. In traditional way, centralized control is commonly adopted for active power allocation, in which, total power reference is dispatched to every wind turbine by a central controller. However, it has several disadvantages, such as complex computation and low flexibility, especially for wind farms with large number of wind turbines. Therefore, a Multi-Agent based collaboration control strategy for active power dispatching in wind farms is proposed to improve operation performance. Firstly, a Multi-Agent based control structure for wind farm is designed, which includes wind turbine agent, group manager agent and central manager agent. Secondly, coordination control strategy among different agents is designed in detail. Finally, a Multi-Agent control model of wind farm is established based on Java/jade platform, and simulation results verify the efficiency of strategy proposed.

关键词： Wind farm

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A real-time wind power control method for power systems with high wind power penetration and its implementation

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Dianli Xitong Zidonghua/Automation of Electric power systems 2015年第21期39卷 23-29页

作者： Wang, Bin Sun, Yong Wu, Wenchuan Zheng, Taiyi Zhang, Boming State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing100084 China Department of Electrical Engineering Tsinghua University Beijing100084 China State Grid Jilin Electric Power Supply Company Changchun130021 China

A real-time wind power control method is proposed to accommodate the severe fluctuation of wind power, which can be used in power systems with high wind power penetration. The maximum allowable wind power generation is estimated online according to the automatic generation control (AGC) downward spinning reserve and the tie-line power deviation. Considering the different priorities for wind farms and the transmission security constraints, different control strategies, such as corrective control to eliminate the transmission congestion, optimal dispatch considering the trade-off between minimum curtailment of wind power and the fairness among wind farms, are integrated in the proposed method. The numerical simulation on the test system and the results of field operation in a provincial power grid show that the method is efficient and practical. © 2015 Automation of Electric power systems Press.

关键词： Wind farm

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Consistency analysis of SCADA data from field power systems 10

Consistency analysis of SCADA data from field power systems

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10th International Conference on Advances in power system control, Operation and Management, APSCOM 2015

作者： Zhang, Yaping Zhang, Hengxu Wang, Liang Hou, Guangsong Key Laboratory of Power System Intelligent Dispatch and Control of the Ministry of Education School of Electrical Engineering Shandong University Jinan China Dispatch and Control Center of Shandong Electric Power Corporation Jinan China Heze Power Supply Company of State Grid Shandong Electric Power Corporation Heze China

ISBN: (纸本)9781849199841

SCADA (Supervisory control And Data Acquisition) system is a basic infrastructure of modern power systems. SCADA data are widely used in applications such as state estimation, power flow calculation, and on-line security assessment. The accuracy of the SCADA data directly affects the implementation of power system automatic control. In practice, the error of the SCADA data may deviate from its factory precision due to the influence of the equipment aging, data transmission and so on. To quantitatively evaluate the validity of the SCADA data, a consistency index is defined in this paper. Some SCADA data from several substations of a power gird is checked with the consistency index to reveal its reliability.

关键词： SCADA systems

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Dynamic Response of Rubbing Happening in a Flexible Rotor-Bearing system

Dynamic Response of Rubbing Happening in a Flexible Rotor-Be...

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2015 International Conference on Electrical, Automation and Mechanical Engineering(EAME 2015)

作者： J.M.Chen D.X.Jiang T.T.Deng J.S.Wang J.L.Zhong S.B.Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal Engineering Tsinghua University Guizhou Electric Power Research Institute

ISBN: (纸本)9781510806528

To reduce the steam loss and raise the efficiency of the steam turbine,the vapour seals are applied in the inner cylinder of the steam *** small gap may easily results in the rubbing happening in the inner ***,the rotor is a flexible *** this paper,dynamic response of rubbing happening in a flexible rotor-bearing system was studied.A simplified flexible rotor-bearing system was constructed,whose rotating speed was between the 1st and 2nd critical rotating *** effect was considered in the analysis,*** rubbing introduce heat and result in the thermally induced *** transient thermal bow was treated as a pair of moments functioning on the shaft segment where rubbing *** shows the amplitude and phase of vibration would be stable after a long *** severity of rubbing affect the stabilization time,which could be regarded as a diagnostic feature to identify the severity of rub happening in a flexible rotor-bearing system.

关键词： thermally induced vibration equivalent thermal moment stabilization time rubbing flexible rotor-bearing system

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Ambient signal based load model parameter identification using optimization method

Ambient signal based load model parameter identification usi...

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IEEE General Meeting power& Energy Society

作者： Xinran Zhang Chao Lu Yingduo Han Songtai Yu Jifeng Wang He Huang Yinsheng Su State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China China Southern Power Grid Guangzhou China

Load modelling is a crucial part in modelling a power system. The complex, nonlinear and stochastic characteristics of power load increase the difficulty of modelling. In this paper, a new approach of ambient signal based load model parameter identification method is proposed to solve this problem. With the proposed method, load model parameter can be identified in any time regardless of the existence of fault. First, Z+M model is simplified to reduce the number of parameters to be identified. Then, parameters of Z+M model are identified with an optimization method, the objective function of which is calculated from WAMS measured power and voltage data. An iterative process is proposed to solve the problem of initial value sensitivity in optimization problems. Finally, the effectiveness of this identification method is validated through the simulation results on WSCC three machines nine nodes system under different operation situation including both small disturbance and large disturbance.

关键词： Load modeling Optimization Integrated circuit modeling Parameter estimation Data models Reactive power power measurement

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Natural Frequency and Dynamic Response of Rotor system of Steam Turbine Modelled with Euler-Bernoulli Beam

Natural Frequency and Dynamic Response of Rotor System of St...

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2015 International power,Electronics and Materials Engineering Conference(IPEMEC 2015)

作者： T.T.Deng J.S.Wang X.J.Li J.L.Zhong S.B.Wang S.P.An W.G.Yang D.X.Jiang Guizhou Electric Power Test and Research Institute State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Thermal EngineeringTsinghua University

ISBN: (纸本)9781510806474

Based on Finite element method(FEM),analysis of natural frequency and dynamics response is carried out in this ***,modeling of rotor system in steam turbines is analyzed with Euler-Bernoulli beam ***,natural frequency of the rotor system is obtained and ***,dynamic response of the rotor system is simulated and the vibration of the rotor system is *** results show that the proposed model can obtain results with high accuracy,and the model is *** modeling approach presented in this work provides a fast and accurate method in analyzing dynamic characteristics of the practical rotor system in steam turbine units

关键词： Natural frequency transient response rotor system steam turbine Euler-Bernoulli Beam

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A random early detection based active queue management algorithm in power optical communication network

A random early detection based active queue management algor...

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作者： Liu, Zhao Tang, Liangrui Yan, Jiangyu State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Changping District Beijing China School of Control and Computer Engineering North China Electric Power University Changping District Beijing China

ISBN: (纸本)9781138028302

According to the different QoS requirements of services in power communication network, a random early detection based active queue management algorithm combined with the differentiated service model is proposed in this paper. The congested queue can take advantage of other idle queues to ensure the QoS requirement of the high priority queue. The simulation shows that the algorithm presented in this paper has better performance in reducing the overall packet loss rate and enhancing the utilization ratio of buffer. © 2015 Taylor & Francis Group, London.

关键词： Quality of service

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A layered interconnected graph model based algorithm for traffic grooming in optical transport network

A layered interconnected graph model based algorithm for tra...

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作者： Dong, Xijie Tang, Liangrui Yan, Jiangyu A State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Changping District Beijing China B School of control and computer engineering North China Electric Power University Changping District Beijing China

ISBN: (纸本)9781138028302

In order to solve the problem of low wavelength resource utilization caused by the huge gap between the capacity need by the service and the single wavelength capacity in OTN, a Layered Interconnected Graph Model (LIGM) based algorithm for Traffic grooming is presented. The LIGM is based on the optical network physical topology, and the costs of every link represent the optical network resources. The initial solution set is calculated with the grooming path optimization selection strategy and the optimal grooming route is chosen from the set with the O/E/O number of each path. By adapting the load balancing mechanism, the algorithm can perfectly solve the problem of traffic grooming in optical networks. The simulation shows that, compared with other traffic grooming algorithms, the algorithm LIGA effectively reduces the blocking probability and makes full use of the optical network resource at the same time. © 2015 Taylor & Francis Group, London.

关键词： Fiber optic networks

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Design and engineering application of automatic discovery system for critical flowgates and security operation rules in power grids

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Dianli Xitong Zidonghua/Automation of Electric power systems 2015年第1期39卷 117-123页

作者： Zhao, Feng Sun, Hongbin Huang, Tianen Guo, Qinglai Wu, Wenchuan Wen, Bojian Department of Electrical Engineering Tsinghua University Beijing100084 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing100084 China Guangdong Power Grid Power Dispatching Control Center Guangzhou510600 China

The framework of an automatic discovery system for critical flowgates and security operation rules in the power grid is designed. Based on the real-time operation data of the power grid, the system is able to automatically find the critical flowgates adapted to the online operation state of the grid. By using the automatic learning method, the system can find the fine rules of critical flowgates as the security operation knowledge of the grid. The functions of the core modules of the system are described, including online automatic discovery of critical flowgates, online calculation of limit transmission capacity of critical flowgates, online generation of mass simulation samples, feature selection, automatic discovery of security operation rules of the power grid. The online application of the system has been realized in Guangdong power grid. The application effect shows that the system is able to generate the security operation knowledge fast enough and refresh it every 15 minutes for online application as required. Meanwhile, the knowledge is capable of not only covering the existing security operation knowledge formulated by experts offline, but also finding new knowledge adapted to the online power grid operation mode, while improving the power grid security and economy.

关键词： Electric power transmission networks

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