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8th Renewable power Generation Conference, RPG 2019

作者： Qu, Chenzhi Lin, Zhongwei Xie, Zhen Li, Yilin Zhang, Shangang Li, Xiongwei Duan, Zhenqing State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control and Computer Engineering North China Electric Power University Beijing102206 China New Energy Co. Ltd Jinan250099 China Guodian New Energy Technology Research Institute Co. Ltd Beijing102209 China

ISBN: (纸本)9781839531255

Wind energy conversion system (WECS) is essentially a time-varying system with high nonlinear characteristics, which leads to the difficulty of guaranteeing the control performance in a wide-scale operating conditions for the conventional linear control strategies. In this paper, a linear-parameter-varying (LPV) gain-scheduled controller is proposed for variable-speed-variable-pitch wind turbines above rated wind speed, which improves both steady- and dynamic-response performances under wide-scale operating conditions. Firstly, the H2/H∞ technique is adopted to reduce the rated power tracking errors, while enhancing the robustness against high-frequency turbulence. Secondly, the regional pole placement technique is applied on WECS, which builds the connections to the dynamic response performance. To verify the effectiveness of the proposed method, the simulation is implemented on the NREL 5 MW wind turbine, which is compared with the conventional local linear control strategy with a full analysis on the related performances. © 2019 Institution of Engineering and Technology. All rights reserved.

关键词： Wind power

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Method for Single-phase Electric Meter Phase Discrimination Based on Multiple Linear Regression

Method for Single-phase Electric Meter Phase Discrimination ...

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

作者： Liqiang Zhang Wei Cong Gang Dong Yun Sun Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan China State Grid Shandong Electric Power Company Jinan China

ISBN: (数字)9781728117225

ISBN: (纸本)9781728117232

The phase information of single-phase electric meter is crucial to improve the level of load management and the quality of modeling. A method for single-phase electric meter phase discrimination based on multiple linear regression (MLR) is proposed. The MLR equation takes the single-phase electric meter voltage as the dependent variable. Meanwhile, it takes the gateway meter voltage, the gateway meter current and the single-phase electric meter current as the independent variables. Each single-phase meter forms a regression equation with the gateway meter A, B and C respectively. The determination coefficients of the three regression equations are calculated. According to the value of the coefficients, the phase of single-phase electric meter is discriminated. An example is given to analyze the proposed method with actual energy meter reading data. The analysis results show that the proposed method has higher accuracy and reliability.

关键词： Meters Mathematical model Logic gates Voltage measurement power supplies Correlation power measurement

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Powpower system state estimation based on Ɛ-fuzzy tree method

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Dianli Xitong Baohu yu Kongzhi/power system Protection and control 2019年第5期47卷 138-144页

作者： Zhang, Yue Shan, Lianfei Yu, Jianming Zhang, Jianan Zhang, Wenguang NARI Group Corporation Co. Ltd. State Grid Electric Power Research Institute Co. Ltd. Nanjing211106 China Beijing KeDong Electric Power Control System Co. Ltd. Beijing100192 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing102206 China

power system state estimation plays an important role in Energy Management system (EMS). To improve the performance of state estimation, a power system state estimation method based on Ɛ-fuzzy tree (Ɛ-FT) is proposed. Taken 500 kV bus of Fuzhou power grid as the research target, the network structure is analyzed to extract the measurement variables information and select the variables, the obtained feature matrix is used as the input of Ɛ-FT to establish the Ɛ-FT model of 500 kV bus voltage amplitude, which is made a comparison with other modeling methods. Then, the bad data of measurement variables is used to validate the robustness of the proposed state estimation method. The results show that the method can effectively resist the bad data of measurement variables, and have higher prediction accuracy and robustness. Besides, the bad data can be limited locally to reduce the impact on the entire power grid state estimation. © 2019, power system Protection and control Press. All right reserved.

关键词： state estimation

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Engineering a High-Selectivity PVDF Hollow-Fiber Membrane for Cesium Removal

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Engineering 2019年第5期5卷 865-871页

作者： Shiyuan Ding Lilan Zhang Yang Li Li’an Hou Institute of Surface-Earth System Science Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim Tianjin UniversityTianjin 300072China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China State Key Laboratory of Water Environment Simulation Beijing Normal UniversityBeijing 100875China Xi’an High-Tech Institute Xi’an 710025China

In this study,a copper ferrocyanide/silica/polyvinylidene fluoride(CuFC/SiO2/PVDF)hollow-fiber composite membrane was successfully synthesized through a facile and effective crosslinking *** PVDF hollow-fiber membrane with embedded SiO2 was used to fix the dispersion of CuFC nanoparticles for cesium(Cs)*** surface morphology and chemical composition of the composite membrane were analyzed using scanning electron microscopy and X-ray photoelectron spectroscopy(XPS).The composite membrane showed a high Cs rejection rate and membrane flux at the three layers of CuFC and 0.5%SiO2,and its Cs rejection rate was not affected by variation in the pH(pH=4–10).The modified membrane could be effectively regenerated many times using ammonium nitrate(NH4NO3).The Cs selectivity performance was verified by an efficient Cs rejection rate(76.25%and 88.67%in 8 h)in a solution of 100 lg L 1 of Cs with 1 mmol L 1 of competing cations(K+and Na+).The CuFC/SiO2/PVDF hollowfiber composite membrane showed a particularly superior removal performance(greater than 90%)in natural surface water and simulated water with a low Cs ***,the CuFC/SiO2/PVDF hollow-fiber composite membrane can be used directly in engineering applications for the remediation of radioactive Cs-contaminated water.

关键词： Cesium removal Composite membrane Copper ferrocyanide Polyvinylidene fluoride

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An improved fault recovery strategy for active distribution network considering LVRT capability of DG

An improved fault recovery strategy for active distribution ...

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8th Renewable power Generation Conference (RPG 2019)

作者： Yongji Cao Weisheng Liu Yi Zhang Hengxu Zhang Key Laboratory of Power System Intelligent Dispatch and Control of the Ministry of Education (Shandong University) Jinan China State Grid Shandong Electric Power Company Jinan China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

The growing integration of distributed generation (DG) has changed the operation characteristics of traditional distribution network, and so the active distribution network (ADN) has emerged. Fault recovery is significant to reduce the loss of power failure, but the traditional control strategy without consideration of DG is no longer suitable for ADN. An improved fault recovery strategy is proposed to coordinate the fault reclosing and the low voltage ride through (LVRT) capability of DG. The influence of fault reclosing on the voltage variation of the point of common coupling (PCC) of DG is analyzed, with different relative locations of fault and PCC, and a critical LVRT voltage is extracted from the scenario where fault reclosing fails. In order to avoid DG outage, a blocking criterion of fault reclosing is presented according to the fault location and the first voltage dip of PCC. Then, the ADN can be split into planned islands considering the balance of DG power and loads and the load priorities, once the fault reclosing is blocked. Moreover, the WAMS Light is implemented for high-speed synchronous data collection and online central control. A case study is conducted to verify the effectiveness of proposed approach.

关键词：

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Performance Evaluation of CFB Unit Combustion system Based on Comprehensive Economics and Entropy Weight Method

Performance Evaluation of CFB Unit Combustion System Based o...

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International Conference on Sensing, Diagnostics, Prognostics, and control (SDPC)

作者： Ce Qin Mingming Gao Hongfu Zhang The State Key Laboratory of Alternate Electric Power System with Renewable Energy Sources School of Control and Computer Engineering North China Electric Power University Beijing China

ISBN: (数字)9781728101996

ISBN: (纸本)9781728102009

A performance evaluation method for the combustion system in the variable load process of circulating fluidized bed (CFB) unit based on the minimum variance control is proposed. Each operating parameter are initially weighted according to the dynamic economic index of the operating parameters, and entropy weight method is used to adjust the weights of operating parameter under different operating conditions. Then, the minimum variance index based on comprehensive economic and entropy weight method is proposed to evaluate the performance of the combustion system of CFB unit, which reduces the polarization effect generated by the single weighting performance evaluation method and improves the objective scientificality of the operating parameter weighting. Finally, a case study on the combustion system of a 300MW CFB unit reveals that the minimum variance index based on the comprehensive economy and entropy weight method can better evaluate the performance of the combustion system in the dynamic process of the unit, compared with the traditional performance evaluation method. It is of great significance to the operational safety and economy of CFB boiler units.

关键词： Combustion Time series analysis Data models Performance evaluation Entropy Indexes Boilers

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A novel method to increase energy density of permanent magnet machine based on multi-physical field analysis

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UPB Scientific Bulletin, Series D: Mechanical Engineering 2020年第4期82卷 79-92页

作者： Zheng, Qingchun Zhao, Yangyang Zhu, Peihao Wang, Sen Liu, Jingna Ma, Wenpeng Li, Xiang Xiao, Yinhong Wang, Naixin Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China School of Computer Science Tianjin University of Technology Tianjin300384 China School of Automation Shenyang Institute of Engineering Shenyang110136 China Baoding Power Supply Company Hebei Electric Power Company State Grid Corporation of China Baoding071000 China

As an important component of all-electric aircraft, the main propulsion machine is developing towards high energy density, high efficiency and high fault tolerance. In order to improve the energy density of main propulsion machine for all-electric aircraft, a novel approach, which can be used for excellent performance improvement of electric machine of all-electric aircraft, is reported in this paper. The analytical formula of energy density is put forward and the design method of high energy density permanent magnet machine is presented. A high energy density machine with rated power of 30kW is designed, and the electromagnetic field simulation analysis, strength and stress structure verification, temperature field simulation analysis and multi-physical field coupling analysis are obtained. A prototype is developed, the experiment platform is established, and experiments are performed. The energy density of main propulsion machine designed is up to 21kW·N·m/kg2, and the index is increased by 3.2 times. The optimal method based on the multi-physical field analysis can be also applied to other high energy density machines. © 2020, Politechnica University of Bucharest. All rights reserved.

关键词： Electromagnetic fields

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Phase-shift full bridge power supply based on SiC devices

Phase-shift full bridge power supply based on SiC devices

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作者： Liu, Guobing Wang, Kui Qu, Cangqi Liu, Shaogang Jia, Qi Li, Yongdong Beijing Shengfeifan Electronic System Technology Development Co. Ltd. Beijing China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

In order to accurately obtain the switching characteristics of SiC MOSFET in practical application, a dual pulse test circuit is used to test the SiC MOSFET in this subject. By analysing the double pulse test circuit and taking into account the parasitic parameters, the effects of different gate resistances (Rg) and the capacitance between gate and source (Cgs) on the switching characteristics of the SiC MOSFET are summarised. Also, a phase-shifted full-bridge power supply based on SiC device is designed, which can be changed from 270 V direct current (DC) to 220 V alternating current (AC)/50 Hz, which consists of two stages. The first stage is the phase shifted full bridge ZVS DC/DC converter, which will boost the 270 V DC to the 350 V DC;the latter is a single-phase full bridge inverter, and the 350 V DC will be converted to the 220 V AC/50 Hz. The power supply uses the SiC MOSFET as the switch tube, which can reduce the switching loss, improve the switching frequency and reduce the volume of the transformer. A rectifier circuit using a SiC Schottky diode, with almost no reverse recovery process, greatly reduced the transformer side parasitic oscillation and improved the efficiency of the power supply. In this study, the design method of the parameters of the power supply is described in detail. Finally, the rationality of the design of the power supply parameters is verified by MATLAB/Simulink simulation and experimental prototypes. © 2018 Institution of Engineering and Technology. All rights reserved.

关键词： MATLAB

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QoE-aware user association and resource allocation for mixed services in heterogeneous networks

QoE-aware user association and resource allocation for mixed...

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第二届材料科学应用与能源材料国际研讨会

作者： Shuxian Li Liangrui Tang Jiangyu Yan State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University School of Control and Computer Engineering North China Electric Power University

In heterogeneous networks(HetNets),user association and resource allocation(UARA) is a great challenge for radio resource management(RRM).In this paper,a novel QoE-aware UARA scheme is *** delay factor is introduced to QoE metric to weight delays' effect on service *** the UARA scheme based on QoE is formulated as an optimization problem which is a mixed integer nonlinear programming(MINLP) *** solve the problem,we adopt the genetic algorithm(GA) and associate the user association and the resource with population and fitness *** the evolutions of genetic algorithm,the optimal UARA scheme can be worked *** simulation results indicate that the proposed scheme can reduce packet loss rate,and improve the system load balancing performance.

关键词： service QoE-aware user association and resource allocation for mixed services in heterogeneous networks

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Optimization of Operation Strategy of Virtual power Plants Involved in Peak Shaving

Optimization of Operation Strategy of Virtual Power Plants I...

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China International Electrical and Energy Conference (CIEEC)

作者： Qiuchen Yun Wenzhong Gao Fang Zhang Lin Cheng Liting Tian School of Electrical Engineering Beijing Jiaotong University Beijing China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (数字)9781728116754

ISBN: (纸本)9781728116761

In recent years, as the consumption rate of renewable energy has increased, the impact of renewable energy on the power grid has also increased. Currently, distribution network system operators and transmission line system operators are unable to acquire and control the operational status of renewable energy sources such as wind power photovoltaics. These phenomena pose a significant challenge to the safety and stability of the operation of the power system. The virtual power plant is a feasible solution, based on the data acquisition terminal of advanced communication technology, decentralized control or centralized control of DER. Based on the virtual power plant, this paper aggregates three types of resources, wind power, photovoltaic, and electric vehicles, which are typical on the supply side and the demand side. Then, the virtual power plant is regarded as a whole to accept the dispatching instructions of the power grid, formulate the operational strategy of the internal resources of the virtual power plant, and participate in the peaking service.

关键词：

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