1,721,065 research outputs found
Specialized Differential Evolution Technique To Solve The Alternating Current Model Based Transmission Expansion Planning Problem
No full textSolving the Transmission Expansion Planning (TEP) problem using the Alternating Current (AC) network model is a recent important trend. This problem is extremely difficult to solve due to its combinatorial nature and the non-linear behavior presented by using the AC network model, and only very few research works had tackled it so far. In this work, an improved and specialized application of Differential Evolution (DE) to solve the TEP problem in its static form, using the AC model and taking into account reactive power compensation is presented. The main goal of this work is to make feasible the use of the AC network model for TEP. This approach improves some features of traditional differential evolution in its binomial version to be applied to solve the TEP problem. Some comparisons are performed using some other swarm based meta-heuristics in order to demonstrate the good results obtained. Test and realistic networks are used to present the results of this new approach.68243251Rider, M.J., Transmission system expansion planning using DC-AC models and non-linear programming techniques (2006) D.Sc. Thesis in Portuguese, , Sao Paulo, Brazil: University of CampinasRomero, R., Monticelli, A., García, A., Haffner, S., Test systems and mathematical models for transmission network expansion planning (2002) IEE Proc-Gener Transm Distrib, 149 (1), pp. 27-36Fang, R., Hill, D., A new strategy for transmission expansion in competitive electricity markets (2003) IEEE Trans Power Syst, 18 (1)Latorre, G., Cruz, R., Areiza, J., Villegas, A., Classification of publications and models on transmission expansion planning (2003) IEEE Trans Power Syst, 18 (2)Romero, R., Rocha, C., Mantovani, J.R.S., Sanchez, I.G., Constructive heuristic algorithm for the DC model in network transmission expansion planning (2005) IEE Proc-Gener Transm Distrib, 152 (2), pp. 277-282Rider, M.J., Garcia, A.V., Romero, R., Power system transmission network expansion planning using AC model (2007) Proc IET Gen, Transm, Distrib, 1 (5), pp. 731-742Bent, R., Toole, G.L., Berscheid, A., Transmission network expansion planning with complex power flow models (2012) IEEE Trans Power Syst, 27 (2)Torres, S.P., Castro, C.A., Rider, M.J., Transmission expansion planning by using DC and AC models and particle swarm optimization (2013) Published in "swarm Intelligence in Electric and Electronic Engineering", , IGI GlobalZhang, H., Heydt, G.T., Vittal, V., Quintero, J., An improved network model for transmission expansion planning considering reactive power and network losses (2013) IEEE Trans Power Syst, 28 (3), pp. 3471-3479Torres, S.P., Castro, C.A., Expansion planning for smart transmission grids using AC model and shunt compensation (2014) IET Gener, Transm Distrib, 8 (5), pp. 966-975Sum-Im, T., Taylor, G.A., Irving, M.R., Song Y.H.(., Differential evolution algorithm for static and multistage transmission expansion planning (2009) IET Gener, Transm Distrib, 3 (4), pp. 365-384Das, S., Suganthan, P.N., Differential evolution: A survey of the state of art (2011) IEEE Trans Evol Comput, 15 (1)Torres, S.P., Castro, C.A., Pringles, R., Guaman, W., Comparison of particle swarm based meta-heuristics for the electric transmission network expansion planning problem (2011) IEEE PES-general Meeting, , Detroit (USA)Wang, H., Murillo-Sanchez, C.E., Zimmerman, R.D., Thomas, R.J., On computational issues of market-based optimal power flow (2007) IEEE Trans Power Syst, 22 (3), pp. 1185-1193Miranda, V., Keko, H., Jaramillo, A., EPSO: Evolutionary particle swarms (2007) Advances, Evolutionary Computing for System Design. Series: Studies in Computational Intelligence, 66, pp. 139-168. , Eds. SpringerParsopoulus, K., Vrahatis, M., Particle swarm optimization and intelligence: Advances and applications Information Science Reference, , USA2010 [ISBN: 978-1-61520-666-7
A New Approach To Defining Corrective Control Actions In Case Of Infeasible Operating Situations
No full textA method that deals with power systems in-feasible operating situations is proposed in this paper. In case these situations occur, appropriate corrective actions must be efficiently obtained and quickly implemented by (a) quantifying the systems unsolvability degree (UD), and (b) determining a corrective control strategy to pull the system back into the feasible operating region. UD is determined through the smallest distance between the infea-sible (unstable) operating point and the feasibility boundary in parameter (load) space. In this paper, control strategies can be obtained by either the proportionality method (PM) or the nonlinear programming based method (NLPM). Capacitor banks, tap changing transformers and load shedding are the usual controls available. The idea of local search of the available controls is used as a way of using the most effective controls and minimizing the computational burden. Simulations have been carried out for small to large systems, under contingency and heavy load situations. It is shown that the proposed method can be a very useful tool in operation planning studies, particularly for voltage stability analysis. © 2001 IEEE.34651Overbye, T.J., A power flow measure for unsolvable cases (1994) IEEE Transactions on Power Systems, 9 (3)Overbye, T.J., Computation of a practical method to restore power flow solvability (1995) IEEE Transactions on Power Systems, 10 (1)Granville, S., Mello, J.C.O., Melo, A.C.G., Application of interior point methods to power flow unsolvability (1996) IEEE Transactions on Power Systems, 11 (2)Castro, C.A., Braz, L.M.C., A new approach to the polar Newton power flow using step size optimization (1997) Proc. of the 29th North American Power Symposium, , Laramie, WY, USADobson, I., Lu, L., Computing an optimum direction in control space to avoid saddle node bifurcation and voltage collapse in electric power systems (1992) IEEE Transactions on Automatic Control, 37 (10)Castro, C.A., Bose, A., Correctability of voltage violations in on-line contingency analysis (1994) IEEE Transactions on Power Systems, 9 (3)(1993) Working Group on Voltage Stability, pp. 75-86. , Suggested techniques for voltage stability analysis, 93TH0 620-5 PWRMurtagh, B.A., Saunders, M.A., (1987) Minos 5.1 Users Guide, , Stanford UniversityPreris, L.L., Sasson, A.M., Investigation of the load-flow problem (1968) Proc. of the IEE, 115 (10)http://www.ee.wsishington.edu/reseEirc
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Hybrid Method For Calculating The Maximum Loading Point Using Continuation Load Flow And Nonlinear Programming Techniques
No full textThe computation of the maximun loading point (MLP) is crucial to power systems operation and control, There are several methodologies proposed to compute it. The continuation load flow (CLF) is very robust, widely known to draw PV curves, and can be also used for computing the MLP. However it has some drawbacks, the procedure may diverge for some cases and it is very conservative for some networks, taking many iterations. Other efficient technique using nonlinear programming (NLP) has been proposed recently. This method presents clear advantages due to the orientation of the process in direction to the MLP. This paper presents a method based on the CLF and NLP . The idea is to compute the MLP taking some features of the CLF combined with characteristics of NLP. With this combination the MLP can be evaluated with more accuracy and efficiency. Simulations for different systems including IEEE test systems are shown to evaluate the performance of the method. Some comparisons of the methodologies are also shown. ©2007 IEEE.19291934Kundur, P., (1994) Power System Stability and Control, , McGraw- HillDefinition and classification of power system stability (2004) IEEE Transactions on Power Systems, 19 (2), pp. 1387-1401. , IEEE/CIGRE, MayVan Cutsem, T., Moisse, C., Mailhot, R., Determination of secure operating limits with respect to voltage collapse (1999) IEEE Transactions on Power Systems, 14 (1), pp. 327-335Souza, A.C.Z., Cañizares, C., Quintana, V., Comparison of performance indices for detection of proximity to voltage colapse (1996) IEEE Transactions on Power Systems, 11 (3), pp. 1441-1450Ajjarapu, V., Christy, C., The continuation power flow: A tool for steady state voltage stability analysis (1992) IEEE Transactions on Power Systems, 7 (1)Zarate, L.A., Castro, C.A., Jose Luis, M.R., Esther, R.R., Fast computation of voltage stability security margins using nonlinear programming techniques (2006) IEEE Transactions on Power Systems, 21 (1), pp. 19-27Zárate, L.A., Castro, C.A., Fast computation of security margins to voltage collapse based on sensitivity analysis (2004) IEE Proceedings - Generation, Transmition and DistributionFlatabø, N., Ognedal, R., Carlsen, T., Voltage stability condition in a power transmission system calculated by sensitivity methods (1990) IEEE Transactions on Power Systems, 5 (4). , NovIrissari, G.D., Wang, X., Mokhtari, S., Maximum loadability of power system using interior point nonlinear optimization method (1997) IEEE Transactions on Power Systems, 12 (1). , FebBedoya, D.B., Castro, C.A., Computation of power systems minimum voltage stability security margins (2006) IEEE/PES POWERCON 2006 International conference on power systems technology, Chongqing, , China, 22-26 OctoberL. M. Braz and C. A. Castro and C. A. F. Murari. A critical evaluation of step size optimization based load flow methods. IEEE Transactions on Power Systems, 15, no. 1:202-207, Feb. 2000Seydel, R., Practical Bifurcation and Stability Analysis. From Equilibrium to Chaos (1994) Springer Interdisciplinary Applied Mathematics, , Second Edition, Springer, New YorkDobson, I., Lu, L., New methods for computing a closest saddle node bifurcation and worst case load power margin for voltage collapse (1993) IEEE Transactions on Power Systems, 8 (3
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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