Wyniki wyszukiwania - Biblioteka Nauki

1

Optimal scheduling of Virtual Power Plant with risk management

100%

Xia Y. , Liu J.

Journal of Power Technologies

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2016

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tom Vol. 96, nr 1

49--56

EN

Due to intense electricity consumption, environmental concerns and technological development, a great number of renewable distributed resources have been widely installed in the distributed network. However, the reality that renewable distributed resources frequently fluctuate under high penetration makes effective use a challenge. Fortunately, with improved communication architecture and control techniques, this could be achieved by a Virtual Power Plant (VPP). VPP can aggregate various resources in a distributed generation portfolio, by creating one single operating profile. The aim of this paper is mainly to analyze optimal scheduling of VPP to maximize its profit, with due consideration given to the uncertainty of renewable energy output, such as wind power, and to make the energy mix respond to system need. A risk quantization method (CVaR) is introduced to deal with uncertainty. This paper presents a VPP scheduling model, which takes VPP total operation cost, traded electricity cost, unit earnings, supply-demand balancing and other constraints into account, with a CVaR assessment method embedded into this model. According to the scenarios generated by uncertainty of wind power output, numerical results for a proposed case are discussed. These results show the expected profit of VPP scheduling is closely associated with different degrees of confidence , which is a great help for VPP operators when making the tradeoff between risk and profit.

2

Lqr-Based Nonlinear Tuning Relay Control Design With Fast Convergence

80%

Yu X. , Xia Y. , Ledwich G. , Oghanna W.

International Journal of Applied Mathematics and Computer Science

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1999

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tom Vol. 9, no 2

313-326

EN

In this article, we present a relay control scheme based on LQR design with fast convergence. This scheme provides a practical and simple way to achieve fast convergence based on the well-known LQR design principle. The controller is a global stabiliser in the sense that for any given initial condition, we can always initialize the controller to drive the system to reach the origin. This controller is tunable in accordance with the position of the system state: the closer to the origin, the larger the control gains, which results in a fast control that maintains bounded control magnitude. It has also been shown that setting matrix Q can significantly influence the tendency of eigenvalues to switch the hyperplane. The relation between matrix Q and the tendency of those eigenvalues has been identified. Simulation results are presented to demonstrate the effectiveness of the scheme.

3

A Generic Methodological Framework for Cyber-ITS : Using Cyber-infrastructure in ITS Data Analysis Cases

80%

Xia Y. , Zhang T. , Wang S.

Fundamenta Informaticae

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2014

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tom Vol. 133, nr 1

35--53

EN

This paper presents a method to capture the computational intensity and computing resource requirements of data analysis in intelligent transportation systems (ITS). These requirements can be transformed into a generic methodological framework for Cyber-ITS, mainly consisting of region-based ITS data divisions and tasks scheduling for processing, to support the efficient use of cyber-infrastructure (CI). To characterize the computational intensity of a particular ITS data analysis, the computational transformation is performed by data-centric and operation-centric transformation functions. The application of this framework is illustrated by two ITS data analysis cases: multi-sensor data fusion for traffic state estimation by integrating rough set theory with Dempster- Shafer (D-S) evidence theory, and geospatial computation on Global Positioning System (GPS) data for advertising value evaluation. To make the design of generic parallel computing solutions feasible for ITS data analysis in these cases, an approach is developed to decouple the region-based division from specific high performance computer (HPC) architecture and implement a prototype of the methodological framework. Experimental results show that the prototype implementation of the framework can be applied to divide the ITS data analysis into a load-balanced set of computing tasks, therefore facilitating the parallelized data fusion and geospatial computation to achieve remarkable speedup in computation time and throughput, without loss in accuracy.

4

Structure Design and Performance Analysis of Substation Area Backup Protection Communication Network in Smart Substation

80%

Chen L. , Zhang K. , Xia Y. , Hu G.

Przegląd Elektrotechniczny

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2013

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tom R. 89, nr 5

182-186

EN

In this paper, the general design of substation area backup protection (SABP) communication network in smart substation is proposed, and taking a practical 220kV smart substation for the application object, the communication network’s specific structure is constructed. Besides, the specific network’s real-time performance is studied based on theoretical analysis and OPNET simulation, and its reliability is calculated according to reliability block diagram and fault tree combining with Bayesian technology. The results show that the two performances can meet the requirements.

PL

W artykule przedstawiono projekt sieci komunikacyjnej na potrzeby rezerwowego systemu zabezpieczeń w obszarze inteligentnej podstacji elektroenergetycznej. Proponowaną strukturę sieci zaimplementowano dla inteligentnej podstacji 220kV. Przeprowadzono także symulacje (OPNET) i analizę teoretyczną wydajności sieci w czasie rzeczywistym oraz parametrycznie określono jej niezawodność.

5

Effects of Short-chain Alcohols on the Phase Behavior, Solubilities and Solubilization Ability in Microemulsion Systems

61%

Xia Y. , Li H. L. , Chai J. L. , Yu X. Y. , Liu J. , Qin C. K. , Chen J. F.

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2009

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tom Vol. 83, nr 2

315-324

EN

The effects of short-chain alcohols on the phase behavior, solubilities and solubilization ability in the microemulsion systems cetyltrimethyl ammonium bromide (CTAB) or cetylpyridinium bromide (CPB) or 1-hexadecyl-3-methylimidazolium bromide (C16mimBr)/1-propanol or 1-butanol or 1-pentanol/n-octane/brine were investigated with the d-g fishlike phase diagram. The phase diagram was affected greatly by alcohols, and the magnitude of the middle phase region in the fish body is in the order 1-propanol greated than greated than 1-butanol greated than1-pentanol. With the carbon chain length becoming shorter, more alcohol molecules are needed to balance the interfacial layer. Nearly all surfactants enter into the interfacial layer and little remains in aqueous or oleic phase. However, alcohols dissolve in the aqueous and oleic phases, besides they enter into the interfacial layer. The solubilization ability of the microemulsion system is mainly affected by the alcohols and the order is 1-pentanol greated than 1-butanol greated than 1-propanol.

6

Investigation on Irreversible Expansion of 1,3,5-Triamino-2,4,6-trinitrobenzene Cylinder

61%

Sun J. , Kang B. , Zhang H. , Liu Y. , Xia Y. , Yao Y. , Liu X.

Central European Journal of Energetic Materials

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2011

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tom Vol. 8, nr 1

69-79

EN

In this study, the irreversible expansion of TATB cylinder is investigated. No evident variation of the lattice parameters is observed on TATB crystal. The density of TATB powder decreases by only about 0.02% after it suffered from thermal cycling process at the range from -54 C to 74 C, while the density of TATB cylinder decreases by about 1.0%. It is suggested that the density variation of TATB powder has little contribution to the density decrease of TATB cylinder. Therefore, the increasing interstices between TATB powder originated from the thermal cycling should be responsible to the irreversible expansion of TATB cylinder.

7

Cloning and characterization of a type 1 metallothionein gene from the copper-tolerant plant Elsholtzia haichowensis

61%

Xia Y. , Lv Y. , Yuan Y. , Wang G. , Chen Y. , Zhang H. , Shen Z.

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2012

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tom 34

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nr 5

EN

EhMT1, a type 1 metallothionein (MT) gene, was cloned from Elsholtzia haichowensis, a Cu-tolerant plant. Typical of plant type 1MTs,EhMT1encodes a putative peptide of 74 amino acid residues containing cysteine-rich domains. Sequence comparisons with various databases revealed strong similarities at the nucleotide and amino acid levels between EhMT1 and the type 1 MT of Mimulus guttatus. EhMT1 transcriptionwas greater in the roots than in the leaves, and was markedly increased by treatments with Cu, H₂O₂, and heat shock. EhMT1-GUS was localized to the cytoplasm of onion epidermal cells. Escherichia coli cells expressing pET-30a-EhMT1 were more tolerant to Cu and accumulated more Cu than control cells. Our results show that EhMT1 is involved in Cu tolerance and accumulation in E. haichowensis.

8

All-region human health risk assessment of Cr(VI) in a coal chemical plant based on Kriging

61%

Zhang K. , Yang J. , Wang Y. , Xia Y. , Liu S. , Zhang R.

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nr 1

9

Analysis of heavy metal sources and health risk assessment of typical coal mine collapsed lakes in Huaibei Coalfield, Anhui Province, China

51%

Li J. , Gui H. , Hu R. , Chen L. , Xia Y. , Fan H. , Yu H. , Wang M.

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nr 5

10

Downregulation of the lycopene ε-cyclase gene confers tolerance to salt and drought stress in Nicotiana tabacum

36%

Shi J. , Liu P. , Xia Y. , Wei P. , Li W. , Zhang W. , Chen X. , Cao P. , Xu Y. , Jin L. , Li F. , Luo Z. , Wei C. , Zhang J. , Xie X. , Qu L. , Yang J. , Lin F. , Wang R.

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tom 37

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nr 10

EN

Lycopene ε-cyclase (ε-LCY) functions at a branch point of the carotenoid biosynthesis pathway and modulates the ratio of lutein to the β-carotenoids. RNA interference (RNAi) and overexpression (OE) of Ntε-LCY were used to evaluate the physiological roles of ε-LCY in Nicotiana tobacum. In leaves, strong accumulation of β branch carotenoids and high expression of carotenoid biosynthesis genes resulted from suppression of Ntε-LCY expression. RNAi plants showed enhanced salt and drought tolerance, while overexpression of the Ntε-LCY gene weakened tolerance to salt and drought stress, as compared to control. Further analysis revealed that RNAi plants exhibited less water loss and had lower reactive oxygen species levels than did WT plants after both the salt and drought treatments. Further, higher levels of ABA accumulated in the RNAi lines than in the WT lines under stress conditions. These results suggest that reduced Ntε-LCY expression can improve drought and salinity tolerance in Nicotiana tabacum by enhancing their ROS scavenging ability.