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A Robust Weighted Combination Forecasting Method Based on Forecast Model Filtering and Adaptive Variable Weight Determination

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ENERGIES 2016年第1期9卷 20页

作者： Li, Lianhui Mu, Chunyang Ding, Shaohu Wang, Zheng Mo, Runyang Song, Yongfeng Beifang Univ Nationalities Coll Mechatron Engn Yinchuan 750021 Peoples R China Harbin Inst Technol State Key Lab Robot & Syst Harbin 150001 Peoples R China State Grid Ningxia Elect Power Design Co Ltd Yinchuan 750001 Peoples R China Qingdao Technol Univ Sch Management Qingdao 266520 Peoples R China Hunan Univ Coll Elect & Informat Engn Changsha 410082 Hunan Peoples R China Sichuan Univ Coll Elect Engn & Informat Chengdu 610065 Peoples R China

Medium-and-long-term load forecasting plays an important role in energy policy implementation and electric department investment decision. Aiming to improve the robustness and accuracy of annual electric load forecasting, a robust weighted combination load forecasting method based on forecast model filtering and adaptive variable weight determination is proposed. Similar years of selection is carried out based on the similarity between the history year and the forecast year. The forecast models are filtered to select the better ones according to their comprehensive validity degrees. To determine the adaptive variable weight of the selected forecast models, the disturbance variable is introduced into Immune Algorithm-Particle Swarm Optimization (IA-PSO) and the adaptive adjustable strategy of particle search speed is established. Based on the forecast model weight determined by improved IA-PSO, the weighted combination forecast of annual electric load is obtained. The given case study illustrates the correctness and feasibility of the proposed method.

关键词： load forecasting robustness combination forecast Markov chain normal cloud model immune algorithm particle swarm optimization

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Rail Inspection Meets Big Data: Methods and Trends

Rail Inspection Meets Big Data: Methods and Trends

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International Conference on Network-Based Information Systems (NBIS)

作者： Qingyong Li Zhangdui Zhong Zhengping Liang Yong Liang Beijing Key Lab of Transportation Data Analysis and Mining Beijing Jiaotong University Beijing China College of Computer Science and Software Engineering Shenzhen University Communication & Power Utilization Technology Subcompany State Grid Electric Power Research Institute State Grid Beijing China

Rail inspection is one of the most important tasks for rail industry, in order to guarantee the safety of railway systems and control their cost. Rail are systematically inspected for defects using various non-destructive evaluation (NDE) techniques, which include ultrasonic inspection, visual detection, magnetic flux leakage method, acoustic emission inspection etc. The data obtained by these NDE devices are going to increase in both quality and quantity, therefore big data has emerged as a potential challenge for rail inspection. This paper reviews the advanced NDE techniques for rail inspection, and brings forward a new framework of rail inspection based on big data, according to the characteristics of inspection data.

关键词： Rails Inspection Acoustics Surface cracks Visualization Surface treatment Big data

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Circulating Unbalanced Currents of EHV/UHV Untransposed Double-Circuit Lines and Their Influence on Pilot Protection

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IEEE TRANSACTIONS ON power DELIVERY 2014年第2期29卷 825-833页

作者： Li, Bin Guo, Fengrui Li, Xuebin Bo, Zhiqin Tianjin Univ Minist Educ Key Lab Smart Grid Tianjin 300072 Peoples R China Tianjin Elect Power Design Inst Tianjin 300400 Peoples R China State Grid Corp China Smart Grid Res Inst Beijing 100052 Peoples R China

This paper elaborates on the reasons for current unbalance in extremely high voltage/ultra-high voltage (UHV) double-circuit transmission-line systems based on analyses of a typical tower structure and feasible phase arrangements. In addition to the studies of the system under normal operation condition, the unbalanced currents of the double-circuit line under the condition of external faults are first investigated. The frequency-dependent model of UHV double-circuit lines is built using the ElectroMagnetic Transients Program including DC (EMTDC) software package. Simulation results and real data obtained from the power utility show that the circulating unbalanced currents in both cases of normal operation and external fault conditions cannot be ignored due to their high magnitude. The significant influence of the circulating unbalanced currents on pilot directional protection of double-circuit lines is proven and verified by various simulation tests and real field data. Consequently, an improved scheme is proposed to overcome the influence of circulating unbalanced current and significantly improve the reliability of pilot directional protection.

关键词： Circulating current unbalance double-circuit transmission line external fault protective relaying ultra-high voltage (UHV)

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analysis of EMI on control signal line of DC power converter of electric vehicle

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INTERNATIONAL JOURNAL OF ELECTRIC AND HYBRID VEHICLES 2014年第1期6卷 39-45页

作者： Li, Tieding Liu, Fenghua An, Zongyu Power Engn Consulting Grp Cent Southern China Elect Power Design Inst China Power Grid Engn Branch 668 Minzhu Rd Wuhan 430071 Hubei Peoples R China Chongqing Univ Equipment & Syst Secur & New Technol State Key Lab Power Transmiss Chongqing 400044 Peoples R China

Development of electric vehicles is promoted by the increasing problems about the severe shortage of oil resources and serious environment pollution at present. The interference produced by the new high-power electronic equipment in electric vehicles will have influence on the equipment that is attached to it, especially the effect it has on the control circuit cannot be ignored. In this paper, in the four typical working states of electric vehicles, research on the conducted interference current features on the control line of DC converter system is done, reasons for interference coupling to the control line are analysed, and the conclusion is drawn that the value of interference current on the control line in starting state and charging state is the maximum and that value decreases in high-speed state and idle-speed state.

关键词： vehicle electric vehicle power electronics converter drive motor electromagnetic compatibility electromagnetic interference propagation path control signal

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design, analysis, and Sensorless Control of a Self-Decelerating Permanent-Magnet In-Wheel Motor

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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2014年第10期61卷 5788-5797页

作者： Fan, Ying Zhang, Li Huang, Jin Han, Xuedong Southeast Univ Sch Elect Engn Nanjing 210096 Jiangsu Peoples R China Jiangsu Key Lab Smart Grid Technol & Equipment Zhenjiang 212009 Peoples R China Wuhu Power Supply Co Wuhu 241000 Peoples R China Jiangsu Elect Power Design Inst Dept New Energy Nanjing 2111100 Jiangsu Peoples R China

This paper is to propose a new self-decelerating permanent-magnet (PM) in-wheel motor for low-speed and high-torque drive of electric vehicles (EVs). This motor uses sensorless control and integrates advantages of magnetic gear and those of PM machine together while gear inner rotor is removed. The key is the magnetic gear, which can reduce the size of the motor and achieve the similar torque amplification provided by a mechanical gearbox and does not require maintenance or cause breakdown issues. The topology and the operating principle of the proposed in-wheel motor are analyzed;the effects of flux modulated by the magnetic gear and the static characteristics are investigated by using the finite-element analysis. To solve the problems of mechanical sensors, an improved sliding model observer for sensorless control is studied. Then, the evaluation of the system performances is conducted by the simulation based on the MATlab/Simulink and the experiment based on a prototype. Both the simulation and the experimental results show that the system can provide low-speed high-torque driving for EVs without mechanical gears and sensors.

关键词： Finite-element analysis (FEA) improved sliding model observer (SMO) magnetic gear permanent-magnet (PM) in-wheel motor self-decelerating

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Coordination of Superconductive Fault Current Limiters With Zero-Sequence Current Protection of Transmission Lines

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IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 2014年第5期24卷 1-5页

作者： Li, Bin Li, Chao Guo, Fengrui Xin, Ying Wang, Chuncheng Pang, Xueyue Tianjin Univ Minist Educ Key Lab Smart Grid Tianjin 300072 Peoples R China Innopower Superconductor Cable Co Ltd Beijing Econ & Technol Dev Area Beijing 100176 Peoples R China Guangdong Elect Power Design Inst Guangzhou 510600 Guangdong Peoples R China

A 500 kV saturated iron-core superconductive fault current limiter (SISFCL) has been designed to be installed in an extra high voltage (EHV) transmission system in southern China. We carried out studies on compatibility and coordination problems in the application of this kind of device in an EHV network. In this paper, the operational principle of an SISFCL and the protection configuration of transmission lines are briefly introduced. The influence of an SISFCL on the zero-sequence current protection of the grid, taking into consideration both the fault of SISFCL itself and fault of the power lines, is discussed. In order to coordinate the SISFCL and the grid protection scheme, requirements and recommendations are proposed. A model of a 500 kV double-circuit transmission system with SISFCLs is built using Electromagnetic Transient Program including DC (EMTDC) software package. The simulation results are in good agreement with the theoretical analyses.

关键词： DC excitation power transmission saturated iron core superconductive fault current limiter (SFCL) zero-sequence current protection

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Investigation of a New Flux-Modulated Permanent Magnet Brushless Motor for EVs

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SCIENTIFIC WORLD JOURNAL 2014年第1期2014卷 540797-540797页

作者： Fan, Ying Gu, Lingling Luo, Yong Han, Xuedong Cheng, Ming Southeast Univ Sch Elect Engn Nanjing 210096 Jiangsu Peoples R China Jiangsu Key Lab Smart Grid Technol & Equipment Zhenjiang 212009 Peoples R China Jiangsu Elect Power Design Inst Dept New Energy Nanjing 2111100 Jiangsu Peoples R China

This paper presents a flux-modulated direct drive (FMDD) motor. The key is to integrate the magnetic gear with the PM motor while removing the gear inner-rotor. Hence, the proposed FMDD motor can achieve the low-speed high-torque output and high-speed compact design requirements as well as high-torque density with a simple structure. The output power equation is analytically derived. By using finite element analysis (FEA), the static characteristics of the proposed motor are obtained. Based on these characteristics, the system mathematical model can be established. Hence, the evaluation of system performances is conducted by computer simulation using the Matlab/Simulink. A prototype is designed and built for experimentation. Experimental results are given to verify the theoretical analysis and simulation.

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Cloud Computing in Electric Vehicles Charging Control and Dispatch Optimization 2

Cloud Computing in Electric Vehicles Charging Control and Di...

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2nd IEEE International Conference on Progress in Informatics and Computing (PIC)

作者： Wu, Dan Liu, Bo Chen, Zhijian Xie, Wenyan Huang, Xiang Pei, Shuwei Sheng, Bin Feng, Donghan China Southern Power Grid Co Ltd Informat Ctr Guangzhou Guangdong Peoples R China Chinese Acad Sci Inst Software State Key Lab Comp Sci Beijing Peoples R China Guangdong Elect Power Design Inst Network & Informat Branch Guangzhou Guangdong Peoples R China Shanghai Jiao Tong Univ Dept Comp Sci & Engn Shanghai 200030 Peoples R China Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200030 Peoples R China

ISBN: (纸本)9781479920303

Charging of large-scale electric vehicles will have a significant impact on the grid so that their charging schedule needs to be optimized. The traditional centralized scheduling method requires high performance in information exchange and computing. Based on the analysis of the features of electric vehicle charging load and the research of cloud computing, we propose a cloud computing based schedule platform for optimal charging of electric vehicles. In addition, the function and implementation of the three basic modules of the platform ( the data collection module, the cloud computing center and the control center) are exposed. The platform performs well in optimal scheduling for electric vehicles. In addition, the platform can also make full use of the computing resource and reduce the communication congestion.

关键词： cloud computing electric vehicle optimal charging service platform

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Evaluation on the thermal stresses of a concrete slab under solar radiation

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International Conference on Structures and Building Materials (ICSBM 2013)

作者： Wang, Jianping Chen, Bo Zheng, Jin Li, Pengyun Guizhou Minzu Univ Coll Civil Engn Guiyang Guizhou Peoples R China Wuhan Univ Technol Key Lab Roadway Bridge & Struct Engn Wuhan Hubei Peoples R China Cent South Architectural Design Inst Co Ltd Wuhan Hubei Peoples R China Guangdong Power Grid Corp Elect Power Res Inst Guangzhou Guangdong Peoples R China

ISBN: (纸本)9783037856611

The time-varying temperature field and stress distribution of a concrete roof slab is actively investigated in this study with the aiding of the commercial package ANSYS. Fine finite element model of the concrete slab is constructed and different boundary conditions are applied to obtain the temperature distribution within the slab. The solar radiation model is utilized to estimate the solar radiation received by the slab and the shelter effects are also taken into consideration. The numerical models can successfully predict the structural temperature gradient and thermal stress distribution at different time. The made observations indicate that the simulated temperature variation of the concrete slab based on the solar radiation model agrees well with measurement results. It is seen that the numerical models can successfully predict the structural time-varying thermal effects.

关键词： Concrete slab thermal stress temperature distribution heat transfer analysis

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analysis on the daily temperature variation of a concrete slab under environmental effects

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International Conference on Structures and Building Materials (ICSBM 2013)

ISBN: (纸本)9783037856611

The dynamic temperature field of a concrete slab is actively studied in this study with the aiding of the commercial package ANSYS. Fine finite element model of the concrete slab is constructed and different boundary conditions are applied to obtain the temperature distribution within the slab with the aid of the commercial software package ANSYS. The solar radiation model is utilized to estimate the solar radiation received by the slab and the shelter effects are also taken into consideration. The numerical models can successfully predict the structural temperature at different time. The made observations demonstrate that the simulated temperature variation of the concrete slab based on the solar radiation model agrees well with measurement results. It is seen that the numerical models can successfully predict the structural temperature field at different time. The methodology employed in the paper can be applied to other concrete structures as well.

关键词： Concrete slab temperature distribution field test heat transfer analysis

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