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IEEE power and Energy Society General Meeting

作者： Jing Yu Ye Guo Hongbin Sun Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen Institute Tsinghua University Shenzhen China State Key Lab of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China

In order to better accommodate renewable energy sources (RESs), a general coordinated mechanism for modern power system has been proposed, which is simultaneously appropriate for economic dispatch and market clearing under the current structure of wholesale markets. In which, the system operator can achieve a global optimum under uncertainties by investing independent aggregators (IAs) with better autonomies on trade-offs between expected profits and risks. Meanwhile, IAs with RESs are free to model their internal uncertainty in a heterogeneous manner and integrate the local information into tailored bids without revealing privacy. Moreover, a parametric-programming-based distributed (PPD) algorithm is designed to support the once-daily communication mechanism. The case studies validated the performance of the proposed mechanism.

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Vertically integrated outdoor in-site line protection based on SoC technique

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全球能源互联网（英文版） 2019年第2期1卷 179-186页

作者： Tonghua Wu Yuping Zheng Yutao Qiu Xiaoping Zhang Gang Yao Jimin Chai Xiaofan Hou College of Energy and Electrical Engineering Hehai University Nanjing 210098 China NARI Group Corporation/State Grid Electric Power Research Institute Nanjing 211106 China State Key Laboratory of Smart Grid Protection and Control Nanjing 211106 China State Grid Zhejiang Electric Power Corporation Hangzhou 310007 China Electrical and System Engineering University of Birmingham Birmingham B152TT UK NARI Group Corporation/State Grid Electric Power Research Institute Nanjing 211106 China State Key Laboratory of Smart Grid Protection and Control Nanjing 211106 China College of Energy and Electrical Engineering Hehai University Nanjing 210098 China

By focusing on the problems of speed, reliability, operation and maintenance in the practical application of line protection in conventional and smart substations, we propose system architecture and a technical scheme for in-site (similar in meaning to on-site or near-process) line protection based on vertical integration and outdoor installation. The functions of the single-bay merging unit, relay protection, and intelligent terminal are vertically integrated to reduce the number and types of devices, simplify the configuration, reduce signal transmission, and shorten the protection action time. In addition, this vertically integrated device is applied to provide data acquisition and control execution support for substation-area protection, security and stability of devices, and other substation-area devices. The vital performance outputs are tested and compared. Finally, the experimental results verify that the proposed scheme is feasible and the technology is advanced.

关键词： Line protection In-site relay protection Merging unit Vertical integration

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Space Charge Behavior in AC Electrically Aged Low-Density Polyethylene Films 2

Space Charge Behavior in AC Electrically Aged Low-Density Po...

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2nd IEEE International Electrical and Energy Conference, CIEEC 2018

作者： Cheng, Zixia Shi, Jinxing Zhang, Ling Zhou, Yuanxiang Lu, Zekai Guo, Shaowei School of Electrical Engineering Zhengzhou University Zhengzhou450001 China State Key Lab of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing100084 China School of Electrical Engineering Xinjiang University Urumqi830047 China Electric Power Research Institute State Grid Jibei Electric Power Company Beijing100045 China

ISBN: (纸本)9781538653913

In order to study the effect of AC aging on space charge characteristics of low-density polyethylene (LDPE) films, an AC electric field of 50 kV/mm (peak value) was adopted for the accelerated aging test and space charge measurements of AC aged LDPE films were carried out subsequently. The results show that no significant space charge accumulation in the LDPE samples aged under a 50 kV/mm AC electric field. It can be seen that a significant positive space charge accumulation occurs inside the sample, when DC electric fields were applied to the AC aged LDPE samples. The long-term AC aging also causes more and deeper cracks on the surface of LDPE samples. Moreover, AC aging promotes the oxidation reaction of LDPE. The longer the aging time, the higher the degree of oxidation. On this basis, the probable relationship between space charge characteristics and material physicochemical properties of LDPE during AC electrical aging is clarified. © 2018 IEEE.

关键词： Electric space charge

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Comparation of Aroma-Active Compounds in Fresh Commercial Infant Formula and the Change during Ambient Storage

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Journal of Future Foods 2025年

作者： Lirong Xu Ailing Tian Jiayi Su Meifan Pan Riqing Liu Peipei Gao Beilei Pang Zitong Liu Lijiao Fan Huaixia Zhang Yali Wang Lei Du Lili Zheng Yingchun Zhao Xiaoxiao Feng Jing Lv Department of Nutrition The Affiliated Hospital of Qingdao University Qingdao China Institute of Nutrition and Health Qingdao University 266071 Qingdao China Department of Gastrointestinal Surgery The Affiliated Hospital of Qingdao University Jiangsu Road 16# Qingdao Shandong 266400 People's Republic of China Department of Health Education and Management and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment School of Public Health Fourth Military Medical University Xi'an China. Department of surgery The Affiliated Hospital of Qingdao University Qingdao China National Engineering Research Centre for Intelligent Electrical Vehicle Power System (Qingdao) College of Mechanical & Electronic Engineering Qingdao University Qingdao 266071 China College of Chemical Engineering Qingdao University of Science and Technology Analysis and Testing Center Qingdao University of Science and Technology 266042 Qingdao China Department of Food Science & Technology School of Agriculture & Biology Shanghai Jiao Tong University Shanghai 200240 China

This study compared the aroma-active compounds in 14 brands of commercially infant formula and investigated their changes during ambient storage after opening for 2 months. A total of 29 major aroma-active compounds were detected in infant formula. From the PCA and heatmap analysis, a total of 14 brands of infant formula were classified into 3 groups, the second group contained JLB-Y, AY and FH-F, of which 2-furanmethanol and (E,E)-3,5-octadien-2-one were mainly compounds, the third group contained YL and JLB-L, the characteristic flavor compounds in this group were mainly hexanal, heptanal, etc. Aldehydes, as the main volatile substances, account for more than half of the total volatiles. Nearly half of the aldehydes showed more significant changes after storage, e.g. hexanal, octanal, (E)-2-octenal and 3-methylbutyraldehyde. The YL and YP-Q produced more saturated aldehydes after storage, the concentration of hexanal in YL-2m and YP-Q-2m was 2138.5 μg/kg and 2004.1μg/kg, respectively. The concentrations of heptanal, octanal, and nonanal also increased relatively significantly, which may lead to a distinct rancid flavor in YL and YP-Q. Besides, among the ketones, (E,E)-3,5-octadien-2-one showed the greatest change after storage, especially in JLB-L. According to sensory evaluation experiments, the milky flavor of infant formulas decreased and fatty, rancid, fishy and grassy flavors were found to have increased to different extents after storage. The current information gap on the concentration and evolution of volatile compounds in commercially available infant formula is filled by this study.

关键词： Infant formula Volatile compounds GC-MS Ambient Storage

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Research on collaborative frequency regulation control strategy of wind farm based on decentralized exit

Research on collaborative frequency regulation control strat...

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8th Renewable power Generation Conference (RPG 2019)

作者： Y. H. Ren P. Song X. S. Wang R. F. Shi School of Control and Computer Engineering North China Electric Power University Beijing 102206 PR China State Grid Jibei Electric Power Research Institute North China Electric Power Research Institute Co. Ltd. Beijing 100045 China Grid-connected Operation Technology for Wind-Solar Storage Hybrid System State Grid Corporation Key Laboratory Beijing 100045 China State Grid Jibei Electric Power Research Institute North China Electric Power Research Institute Co. Ltd. Beijing 100045 China

ISBN: (数字)9781839531248

ISBN: (纸本)9781839531255

When the wind turbine adopts the rotor inertia control to participate in grid frequency regulation, it is easy to cause the second frequency drop, which will be more serious when applied to the wind farm. To solve this problem, the influence of wind speed on the unit's ultimate support time under the constant power support mode is analyzed quantitatively and wind turbine recovery time is defined. The functional relationship between the unit's support time and recovery time suitable for engineering application is given. A wind farm frequency regulation optimization model aiming at the longest supporting time of all units in the whole station is established, and the wind farm coordinated frequency regulation control strategy based on decentralized exit is proposed, taking full account of capacity differences of units under different working conditions. Simulation examples show that the real-time coordination of the exit of the wind turbine frequency regulation can effectively alleviate the secondary frequency drop problem of a wind farm.

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Extended Disturbance Observer Based Execution Adjustment Estimation Method of Dynamic Demand Response

Extended Disturbance Observer Based Execution Adjustment Est...

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International Conference on control, Automation and Information Sciences (ICCAIS)

作者： Yaqing Zhao Xin Shan Wenjun Bi Ying Wang Kun Yuan Kaifeng Zhang School of Cyber Science and Engineering Southeast University Nanjing China System R&D Center NARI Group Corporation (State Grid Electric Power Research Institute) Nanjing China Key Laboratory of Measurement and Control of CSE Southeast University Nanjing China

ISBN: (数字)9781728123110

ISBN: (纸本)9781728123127

Since Dynamic demand response (DDR) has the characteristics of large quantity and uncertainty, it is difficult to get accurate response power in real time. At the same time, it is very important to know the execution adjustment of DDR accurately and quickly for updating DDR control strategy and frequency regulation of power system. In this paper, we design an extended disturbance observer (EDO) to estimate the execution adjustment of DDR. Firstly, in order to facilitate the design of estimation scheme, a simplified load frequency control (LFC) model is obtained by using model fitting method. Then, by combining the load variation with tie-line power exchange as an extended disturbance, a reduced-order LFC model of power system is derived. Finally, based on the reduced-order LFC model, EDO can be designed by pole-assignment method. The execution adjustment of DDR can be obtained by subtracting the measured value of tie-line power from the estimated value of the observer. From the simulation results of a multi-area LFC control system, the effectiveness of the proposed scheme is demonstrated.

关键词： Frequency control power system dynamics Load modeling Disturbance observers

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A Semi-smooth Projected Levenberg-Marquardt power Flow Method to Cope With the Constraints Exchange Issue

A Semi-smooth Projected Levenberg-Marquardt Power Flow Metho...

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IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Yuntao Ju Jiankai Wang Zifeng Zhang Jianhua Chen Mingyu Dong Dezhi Li Kun Shi Haibo Zhang College of Information and Electrical Engineering China Agricultural University Beijing China Power control center State Grid Jibei Electric Power Company Beijing China Beijing Key Laboratory of Demand Side Multi-Energy Carriers Optimization and Interaction Technique Beijing China China Electric Power Research Institute Beijing China The State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China

ISBN: (数字)9781728131375

ISBN: (纸本)9781728131382

In the conventional power flow (PF) calculation, when using the PV-PQ bus switching to deal with the problem of the generator buses reactive power limits violation for power systems, this method may cause the power flow calculation to fail. If using the Fischer-Burmeister (FB) function to handle constraint exchange issues, then using the Newton-Raphson (NR) method to solve PF, this operation will lead to a slow convergence. In this paper, a semi-smooth projected Levenberg-Marquardt (PLM) power flow method based on the FB function to deal with the constraints exchange issues is proposed. This method can change the search direction when the constraint exchange positions are at sharp corners, and adjust the size of the trust region to prevent the power flow from divergence due to excessive step size in the iterative process, thus improving convergence and reliability. Furthermore, the traditional power flow calculation method is sensitive to the initial value, which may cause the PF divergence, however the method of PLM proposed in this paper is globally convergent, which is not sensitive to the initial value. Numerical tests implemented on a small 3-bus network and a modified IEEE 118-bus system show that the proposed method is more efficient and robust than existing methods.

关键词： Load flow Convergence Reactive power Mathematical model Optimization Generators

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Risk assessment of contract execution in large consumer direct power purchase

Risk assessment of contract execution in large consumer dire...

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International Conference on Mechanical, Electric and Industrial engineering, MEIE 2018

作者： Wang, Qianru Wang, Zhibo Dai, Yong Xia, Tian Zhang, Qian Li, Weidong School of Electrical Engineering Dalian University of Technology Dalian116024 China Nanri Group Corporation State Grid Electric Power Research Institute Nanjing210003 China Beijing Kedong Electric Power Control System Co. Ltd Beijing100194 China State Grid Gansu Electric Power Corporation GANSU730050 China

Nowadays, China is steadily advancing the reform of the electricity market. The direct power purchase by large consumers, as an important form of which has the characteristics of large participation of renewable energy and huge trading power, has a very important impact on the stability of the power system. Therefore, it is necessary to carry out an effective risk assessment method on the bilateral user transactions of supply and demand side, and to reasonably control the risk factors that have greater risk. Direct power purchase by large consumers involve both sides of supply and demand and many possible risk factors. We construct the risk assessment index system from five aspects and the corresponding 17 second-level evaluation indexes are established as AHP method to evaluate the risk. In addition, after rating the risk factors, the weights are determined and the consistency is verified. The results show that AHP can balance the subjective and objective factors and determine the relative weight of each evaluation index. It can also calculate the subordination degree of risk index to each level of risk level and achieve the combination of qualitative and quantitative analysis so that the result of risk assessment is more scientific and accurate. © Published under licence by IOP Publishing Ltd.

关键词： Risk assessment

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Correction to: Economic evaluation of the life cycle of a wind farm and improving the levelized cost of energy in region Champagne-Ardenne, France

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International Journal of Energy and Environmental engineering 2021年第2期13卷 871-871页

作者： Zaoui, Abdelouahab Meziane, Rachid Chatelet, Eric Lakdja, Fatiha Tazi, Nacef Bouzidi, Youcef Electro-Technical Engineering Laboratory Faculty of Technology University of Saida Saïda Algeria Department of Electrical Engineering University of Saida Saïda Algeria Charles Delaunay Institute LM2S/STMR CNRS University of Technology of Troyes Troyes France Intelligent Control and Electric Power System Laboratory (ICEPS) Djillali Liabes University of Sidi-Bel-Abbes Sidi Bel Abbes Algeria

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Preventive control for combined heat and power system: A day-ahead security constrained economic dispatch model 11

Preventive control for combined heat and power system: A day...

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11th IET International Conference on Advances in power system control, Operation and Management, APSCOM 2018

作者： Lin, Qunli Shen, Xinwei Xu, Yinliang Sun, Yong Li, Zhenyuan Guo, Qinglai Sun, Hongbin Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen Institute Tsinghua University Shenzhen China Jilin Power Grid Company State Grid Corp. of China Jilin China State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781839530043

Integrated Energy system (IES), which plays a vital role in the development of Energy Internet (EI), can improve the efficiency of energy utilization and integration of renewable energy. However, the coupling between multiple energy systems will bring new challenges to the security control of the IES, such as combined heat and power (CHP) system. For IES, the preventive control is the first line of defense to ensure that the system can keep stable operation when contingencies such as the transmission outage or generator outage happen. This paper proposes a preventive control approach for CHP system, in which a day-ahead security constrained economic dispatch (SCED) model of CHP system considering the coupling of heat and electric is formulated. The model aims to minimize the cost of the whole system, while the preventive control of the system can be achieved with the constraints considering the normal states and contingencies states. Case studies based on the IEEE 9-bus system with CHPs are presented to illustrate the approach. The case result shows that the combined electric and heat optimal dispatch is more economical than when two systems are independently optimized and operated. And the proposed preventive control approach of the CHP system can satisfy both the electric and heat demand, and system security is ensured when the N-1 contingencies happened. © 2018 Institution of engineering and Technology. All rights reserved.

关键词： Internet of Energy

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