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Impact of renewable energies on the operation and economic situation of coal fired power stations: Actual

Hans-Joachim KRAUTZ, Alexander LISK, Joachim POSSELT, Christian KATZER

《能源前沿(英文)》 2017年 第11卷 第2期   页码 119-125 doi: 10.1007/s11708-017-0468-4

摘要: Due to the fluctuating character of the renewable energy sources the demand of conventional power plants for flexibility is increasing. In the recent years, in Germany there has been a fast rise of production capacity of renewable energies, especially from wind turbines, photovoltaic installations, and biomass plants. The installed nominal power of wind turbines is actually (December 2016) 42 GW and of photovoltaic installations 40?GW. The renewable electric energy production in Germany is about 190?TWh/a, which represents a share of 33% of the yearly demand. The increased need for flexibility affects both the power gradients as well as the minimum load of conventional power plants. Due to this flexibility behaviour, conventional power plants are faced with problems concerning the durability of power plant components, corrosion, more maintenance effort and consequently the overall life expectancy. Another consequence of the increasing share of renewable energies is the decreasing full load operating hours, especially of coal fired and gas power plants. Along with decreasing revenues from the energy exchange market, coal fired power plants are faced with new economically challenges.

关键词: flexible load operation     minimal load     power gradients     power plant maintenance     corrosion     life expectancy    

Optimal dispatch of multi energy system using power-to-gas technology considering flexible load on user

Zi LING, Xiu YANG, Zilin LI

《能源前沿(英文)》 2018年 第12卷 第4期   页码 569-581 doi: 10.1007/s11708-018-0595-6

摘要:

The relation between power-to-gas technology (P2G) and energy interconnection becomes increasingly close. Meanwhile, the participation of flexible load on user side in system optimization has attracted much attention as an efficient approach to relieve the contradiction between energy supply and energy demand. Based on the concept of energy hub, according to its series characteristic, this paper established a generic multi-energy system model using the P2G technology. The characteristic of flexible load on user side was considered and optimal dispatch analysis was made, so as to reduce the cost, to reasonably dispatch the flexible load, to reduce the discharge, to enhance the new energy output, and to increase the power-to-gas conversion efficiency. Finally, a concrete analysis was made on the optimal dispatch result of the multi-energy system using the P2G technology considering flexible load on user side in the calculating example, and optimal dispatch of the system was verified via four different scenarios. The results indicate that cooperative dispatch of multi-energy system using the P2G technology considering flexible load on user side is the most economic, and can make a contribution to absorption of new energy and P2G conversion. In this way, environmental effects and safe and stable operation of the system can be guaranteed.

关键词: multi-energy system     energy hub     series characteristic     optimal dispatch     flexible load    

A new technique for islanding operation of distribution network connected with mini hydro

J. A. LAGHARI,H. MOKHLIS,M. KARIMI,A. H. A. BAKAR,Hasmaini MOHAMAD

《信息与电子工程前沿(英文)》 2015年 第16卷 第5期   页码 418-427 doi: 10.1631/FITEE.1400309

摘要: An islanding operation of a distribution network is a topic of interest due to the significant penetration of distributed generation (DG) in a power system network. However, controlling the frequency of an islanded distribution system remains an unresolved issue, especially when the load exceeds the generation. This paper presents a new technique for a successful islanding operation of a distribution network connected with multiple mini hydro based DGs. The proposed technique is based on three main parts. The first part uses an islanding detection technique to detect the islanding event correctly. The second part consists of a power imbalance estimation module (PIEM), which determines the power imbalance between the generation and load demand. The third part consists of a load shedding controller, which receives the power imbalance value and performs load shedding according to load priority. The proposed technique is validated on an 11 kV existing Malaysia distribution network. The simulation results show that the proposed technique is effective in performing a successful islanding operation by shedding a significant number of loads.

关键词: Islanding operation     Mini hydro     Distributed generation (DG)     Islanding detection     Load shedding    

Large eddy simulation of a 660 MW utility boiler under variable load conditions

Haoshu SHEN, Yuxin WU, Minmin ZHOU, Hai ZHANG, Guangxi YUE, Junfu LYU

《能源前沿(英文)》 2021年 第15卷 第1期   页码 124-131 doi: 10.1007/s11708-020-0659-2

摘要: Large eddy simulation (LES) has become a promising tool for pulverized coal combustion with the development of computational fluid dynamics (CFD) technologies in recent years. LES can better capture the unsteady features and turbulent structures of coal jet flame than Reynolds averaged Navier Stokes (RANS). The coal-fired power plants in China are now required to be operated in a wide load range and quickly respond to the electric grid. The boiler performance of variable loads should be evaluated in terms of flow, heat transfer, and combustion processes. In this paper, LES was applied to simulate a 660 MW ultra-supercritical boiler under BMCR (boiler maximum continue rate), 75%THA-100, and 50%THA-100 conditions. The predicted gas velocities agree well with the thermal calculation and the temperature error is less than 130 K. The simulation results show that the operation load has significant effects on the boiler performance. It is also proved that LES can provide guidance for the design and operation of advanced coal-fired boilers.

关键词: large eddy simulation     ultra-supercritical boiler     operation load    

柔性材料对爆炸载荷的缓冲效应研究

于少娟,李永池,刘颢文,孙宇新,胡秀章

《中国工程科学》 2007年 第9卷 第4期   页码 75-78

摘要:

建立了柔性材料桙钢复合壳体在爆炸载荷作用下应力波传播问题的完备方程组;使用有限元方法完成 了对复合壳体在爆炸载荷作用下应力波传播规律的系列数值模拟,并着重讨论了不同炸药层和柔性材料层厚度 对柔性材料与钢交界面载荷的影响。

关键词: 柔性材料     爆炸载荷     载荷改造     数值模拟    

Applications of thermostatically controlled loads for demand response with the proliferation of variable renewable energy

Meng SONG, Wei SUN

《能源前沿(英文)》 2022年 第16卷 第1期   页码 64-73 doi: 10.1007/s11708-021-0732-5

摘要: More flexibility is desirable with the proliferation of variable renewable resources for balancing supply and demand in power systems. Thermostatically controlled loads (TCLs) attract tremendous attentions because of their specific thermal inertia capability in demand response (DR) programs. To effectively manage numerous and distributed TCLs, intermediate coordinators, e.g., aggregators, as a bridge between end users and dispatch operators are required to model and control TCLs for serving the grid. Specifically, intermediate coordinators get the access to fundamental models and response modes of TCLs, make control strategies, and distribute control signals to TCLs according the requirements of dispatch operators. On the other hand, intermediate coordinators also provide dispatch models that characterize the external characteristics of TCLs to dispatch operators for scheduling different resources. In this paper, the bottom-up key technologies of TCLs in DR programs based on the current research have been reviewed and compared, including fundamental models, response modes, control strategies, dispatch models and dispatch strategies of TCLs, as well as challenges and opportunities in future work.

关键词: thermostatically controlled load     demand response     renewable energy     power system operation    

Piezoelectric pump with flexible venous valves for active cell transmission

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0712-4

摘要: The development of organ-on-a-chip systems demands high requirements for adequate micro-pump performance, which needs excellent performance and effective transport of active cells. In this study, we designed a piezoelectric pump with a flexible venous valve inspired by that of humans. Performance test of the proposed pump with deionized water as the transmission medium shows a maximum output flow rate of 14.95 mL/min when the input voltage is 100 V, and the pump can transfer aqueous solutions of glycerol with a viscosity of 10.8 mPa·s. Cell survival rate can reach 97.22% with a yeast cell culture solution as the transmission medium. A computational model of the electric-solid-liquid multi-physical field coupling of the piezoelectric pump with a flexible venous valve is established, and simulation results are consistent with experimental results. The proposed pump can help to construct the circulating organ-on-a-chip system, and the simple structure and portable application can enrich the design of microfluidic systems. In addition, the multi-physical field coupling computational model established for the proposed piezoelectric pump can provide an in-depth study of the characteristics of the flow field, facilitating the optimal design of the micro-pump and providing a reference for the further study of active cell transport in organ-on-a-chip systems.

关键词: venous valve     flexible venous valve     cell transmission     organ-on-a-chip system     piezoelectric device    

Creation and integration mechanism of instrumentation flexible developing system

Xiaoli XU, Qiushuang LIU

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 235-240 doi: 10.1007/s11465-011-0122-5

摘要:

To solve many key technical problems during the development of modern instrumentation system integration and provide a new mode and fundamental technical equipment for the research and development (R&D) of modern instrumentation products, based on the concept of an instrumentation flexible developing system (IFDS), this paper discusses the creation and open flexible integration mechanism, perfects the integrated supporting environment and integrated system of the flexible interconnection, and constructs the new flexible integrated system. Based on the operation mechanism of the modern instrumentation developing system and the research and optimization of the rapid integration design method, the paper emphasizes the dynamic integrating method of multiple types of knowledge in a modern instrument R&D system, to effectively utilize the rich integrated resource and achieve rapid integration of the system. Applications show that the new IFDS can improve the integration level and efficiency of R&D of the modern instrumentation system, enforce the reliability of the system, shorten the R&D period, and reduce the development costs.

关键词: modern instrumentation developing     flexible interconnection     flexible integration mechanism     rapid integration system     dynamic integrating method    

Review on flexible perovskite photodetector: processing and applications

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-023-0749-z

摘要: Next-generation optoelectronics should possess lightweight and flexible characteristics, thus conforming to various types of surfaces or human skins for portable and wearable applications. Flexible photodetectors as fundamental devices have been receiving increasing attention owing to their potential applications in artificial intelligence, aerospace industry, and wise information technology of 120, among which perovskite is a promising candidate as the light-harvesting material for its outstanding optical and electrical properties, remarkable mechanical flexibility, low-cost and low-temperature processing methods. To date, most of the reports have demonstrated the fabrication methods of the perovskite materials, materials engineering, applications in solar cells, light-emitting diodes, lasers, and photodetectors, strategies for device performance enhancement, few can be seen with a focus on the processing strategies of perovskite-based flexible photodetectors, which we will give a comprehensive summary, herein. To begin with, a brief introduction to the fabrication methods of perovskite (solution and vapor-based methods), device configurations (photovoltaic, photoconductor, and phototransistor), and performance parameters of the perovskite-based photodetectors are first arranged. Emphatically, processing strategies for photodetectors are presented following, including flexible substrates (i.e., polymer, carbon cloth, fiber, paper, etc.), soft electrodes (i.e., metal-based conductive networks, carbon-based conductive materials, and two-dimensional (2D) conductive materials, etc.), conformal encapsulation (single-layer and multilayer stacked encapsulation), low-dimensional perovskites (0D, 1D, and 2D nanostructures), and elaborate device structures. Typical applications of perovskite-based flexible photodetectors such as optical communication, image sensing, and health monitoring are further exhibited to learn the flexible photodetectors on a deeper level. Challenges and future research directions of perovskite-based flexible photodetectors are proposed in the end. The purpose of this review is not only to shed light on the basic design principle of flexible photodetectors, but also to serve as the roadmap for further developments of flexible photodetectors and exploring their applications in the fields of industrial manufacturing, human life, and health care.

关键词: photodetector     perovskite     flexible     processing     application    

A review of the scalable nano-manufacturing technology for flexible devices

Wenbin HUANG,Xingtao YU,Yanhua LIU,Wen QIAO,Linsen CHEN

《机械工程前沿(英文)》 2017年 第12卷 第1期   页码 99-109 doi: 10.1007/s11465-017-0416-3

摘要:

Recent advances in electronic and photonic devices, such as artificial skin, wearable systems, organic and inorganic light-emitting diodes, have gained considerable commercial and scientific interest in the academe and in industries. However, low-cost and high-throughput nano-manufacturing is difficult to realize with the use of traditional photolithographic processes. In this review, we summarize the status and the limitations of current nano-patterning techniques for scalable and flexible functional devices in terms of working principle, resolution, and processing speed. Finally, several remaining unsolved problems in nano-manufacturing are discussed, and future research directions are highlighted.

关键词: flexible nano-manufacturing     flexible devices     nanofabrication     scalability    

Analytical dynamic solution of a flexible cable-suspended manipulator

Mahdi BAMDAD

《机械工程前沿(英文)》 2013年 第8卷 第4期   页码 350-359 doi: 10.1007/s11465-013-0271-9

摘要:

Cable-suspended manipulators are used in large scale applications with, heavy in weight and long in span cables. It seems impractical to maintain cable assumptions of smaller robots for large scale manipulators. The interactions among the cables, platforms and actuators can fully evaluate the coupled dynamic analysis. The structural flexibility of the cables becomes more pronounced in large manipulators. In this paper, an analytic solution is provided to solve cable vibration. Also, a closed form solution can be adopted to improve the dynamic response to flexibility. The output is provided by the optimal torque generation subject to the actuator limitations in a mechatronic sense. Finally, the performance of the proposed algorithm is examined through simulations.

关键词: parallel robot     flexible cable     suspended robot     dynamic    

Neural Operation Management: A New Avenue for Productive and Military Operations

Qing-guo Ma

《工程管理前沿(英文)》 2014年 第1卷 第3期   页码 304-307 doi: 10.15302/J-FEM-2014039

摘要: An important effect of technological progress is the increasing replacement of manual labor by mental labor in productive and military operations. The variation of the operator’s capabilities in cognition, judgment and decision-making has drawn much attention from operation management researchers. Monitoring and evaluation of these capabilities is especially significant in conditions such as long-time operation, operation with special properties and operation under special circumstances. The military power and economic power are both the key concerns for a nation. The military power depends not only on the weapon system, but also the operators’ capabilities of manipulating the system. Similarly, the economic power is not only dependent on advanced machine system, but also the operational capability of the operators. Thus it has become a hot field of research and practice to monitor and assess the operator’s physiological and psychological states online based on neural measurement technology, and then to give real time intervention, so as to reduce the occurrence of accidents and increase the operation performance.

关键词: operation management     productive operation     military operation     neural operation management     neuromanagement    

Possible role of power-to-heat and power-to-gas as flexible loads in German medium voltage networks

Mark KUPRAT, Martin BENDIG, Klaus PFEIFFER

《能源前沿(英文)》 2017年 第11卷 第2期   页码 135-145 doi: 10.1007/s11708-017-0472-8

摘要: Germany’s energy transition triggered a rapid and unilateral growth of renewable energy sources (RES) in the electricity sector. With increasing shares of intermittent RES, overcapacities during periods of strong wind and photovoltaic electricity generation occur. In the face of insufficient transmission capacities, due to an inhibited network extension, the electricity generation has to be curtailed. This curtailment of RES leads to economic losses and could be avoided through flexible loads. As an option to cope with those problems, the technologies of power-to-gas (PtG) and power-to-heat (PtH) are presented in this paper. First, the alkaline electrolyzer (AEL), polymer electrolyte membrane electrolyzer (PEMEL), and solid oxide electrolyzer cell (SOEC) are investigated regarding their operational parameters. Second, the electric boiler, electrode heating boiler, and heat pumps are considered. Ultimately, the network-supporting abilities and the potential to provide ancillary services, such as control power, load sequence operation, cold start and part load capability, are compared among one another.

关键词: power-to-gas     power-to-heat     flexible loads     ancillary services     coherent energy systems    

复合柔性结构航天器动力学建模研究

曲广吉,程道生

《中国工程科学》 1999年 第1卷 第2期   页码 52-56

摘要:

柔性航天器动力学建模的传统方法是采用混合坐标法,针对中心刚体带大型柔性附件类的航天器,这种方法在理论建模和工程应用方面都获得了极大的成功。在中心刚体加柔性附件类航天器柔性动力学研究成果基础上,通过计及柔性体与柔性体连接点间的复合位移变形,利用混合坐标法建立了复合柔性结构航天器动力学模型,其软件系统DASFA 2.0已初步用于工程分析设计。

关键词: 航天器     复合柔性结构     柔性动力学     混合坐标法    

Estimation of flexible pavement structural capacity using machine learning techniques

Nader KARBALLAEEZADEH, Hosein GHASEMZADEH TEHRANI, Danial MOHAMMADZADEH SHADMEHRI, Shahaboddin SHAMSHIRBAND

《结构与土木工程前沿(英文)》 2020年 第14卷 第5期   页码 1083-1096 doi: 10.1007/s11709-020-0654-z

摘要: The most common index for representing structural condition of the pavement is the structural number. The current procedure for determining structural numbers involves utilizing falling weight deflectometer and ground-penetrating radar tests, recording pavement surface deflections, and analyzing recorded deflections by back-calculation manners. This procedure has two drawbacks: falling weight deflectometer and ground-penetrating radar are expensive tests; back-calculation ways has some inherent shortcomings compared to exact methods as they adopt a trial and error approach. In this study, three machine learning methods entitled Gaussian process regression, M5P model tree, and random forest used for the prediction of structural numbers in flexible pavements. Dataset of this paper is related to 759 flexible pavement sections at Semnan and Khuzestan provinces in Iran and includes “structural number” as output and “surface deflections and surface temperature” as inputs. The accuracy of results was examined based on three criteria of , , and . Among the methods employed in this paper, random forest is the most accurate as it yields the best values for above criteria ( =0.841, =0.592, and =0.760). The proposed method does not require to use ground penetrating radar test, which in turn reduce costs and work difficulty. Using machine learning methods instead of back-calculation improves the calculation process quality and accuracy.

关键词: transportation infrastructure     flexible pavement     structural number prediction     Gaussian process regression     M5P model tree     random forest    

标题 作者 时间 类型 操作

Impact of renewable energies on the operation and economic situation of coal fired power stations: Actual

Hans-Joachim KRAUTZ, Alexander LISK, Joachim POSSELT, Christian KATZER

期刊论文

Optimal dispatch of multi energy system using power-to-gas technology considering flexible load on user

Zi LING, Xiu YANG, Zilin LI

期刊论文

A new technique for islanding operation of distribution network connected with mini hydro

J. A. LAGHARI,H. MOKHLIS,M. KARIMI,A. H. A. BAKAR,Hasmaini MOHAMAD

期刊论文

Large eddy simulation of a 660 MW utility boiler under variable load conditions

Haoshu SHEN, Yuxin WU, Minmin ZHOU, Hai ZHANG, Guangxi YUE, Junfu LYU

期刊论文

柔性材料对爆炸载荷的缓冲效应研究

于少娟,李永池,刘颢文,孙宇新,胡秀章

期刊论文

Applications of thermostatically controlled loads for demand response with the proliferation of variable renewable energy

Meng SONG, Wei SUN

期刊论文

Piezoelectric pump with flexible venous valves for active cell transmission

期刊论文

Creation and integration mechanism of instrumentation flexible developing system

Xiaoli XU, Qiushuang LIU

期刊论文

Review on flexible perovskite photodetector: processing and applications

期刊论文

A review of the scalable nano-manufacturing technology for flexible devices

Wenbin HUANG,Xingtao YU,Yanhua LIU,Wen QIAO,Linsen CHEN

期刊论文

Analytical dynamic solution of a flexible cable-suspended manipulator

Mahdi BAMDAD

期刊论文

Neural Operation Management: A New Avenue for Productive and Military Operations

Qing-guo Ma

期刊论文

Possible role of power-to-heat and power-to-gas as flexible loads in German medium voltage networks

Mark KUPRAT, Martin BENDIG, Klaus PFEIFFER

期刊论文

复合柔性结构航天器动力学建模研究

曲广吉,程道生

期刊论文

Estimation of flexible pavement structural capacity using machine learning techniques

Nader KARBALLAEEZADEH, Hosein GHASEMZADEH TEHRANI, Danial MOHAMMADZADEH SHADMEHRI, Shahaboddin SHAMSHIRBAND

期刊论文