Browsing by Author "Contreras, J."

Now showing 1 - 18 of 18
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    A Principal-Agent Approach to Transmission Expansion-Part I: Regulatory Framework
    (IEEE, 2013) Molina Castro, Juan David; Contreras, J.; Rudnick van de Wyngard, Hugh
    Different regulatory frameworks have implemented competitive mechanisms to increase efficiency in transmission, a natural monopoly. Conflicts of interest and hidden costs make necessary to define methods to obtain an appropriate valuation of new transmission assets. This paper is the first one of a two-paper series and presents the fundamentals of transmission project valuation and cost allocation. We show the fundamentals of non-cooperative game theory, different concepts of game equilibria (Nash, Stackelberg, and Berge), and solutions to the bilateral negotiation problem (Nash bargaining solution, Kalai-Smorodinsky, and Rubinstein). In addition, the design of mechanisms, the information revelation principles, and incentive compatibility issues are described. We propose a model composed of three elements: valuation of a transmission project based on a linear contract, a principal-agent model to determine the optimal effort of an agent developing the transmission project, and the optimal bilateral negotiation of right-of-way costs. We define a method to evaluate the offers to build a transmission line project as a function of the number of agents bidding for it. The value of the project is a function of both the incentives and the valuation of the right-of-way costs. In part two of this series, we present two case studies: the IEEE 24-bus RTS and the Sistema Interconectado Central (SIC) in Chile, where we apply the methodology to a real network.
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    A Principal-Agent Approach to Transmission Expansion-Part II: Case Studies
    (IEEE, 2013) Molina Castro, Juan David; Contreras, J.; Rudnick van de Wyngard, Hugh
    This paper is the second of a two-paper series and presents a model to assess and promote investment projects defined in a plan of expansion of the transmission. We propose a model that consists of three main elements: valuation of a project based on the design of a linear contract, a principal-agent model to assess the optimal effort of an agent, and the right-of-way negotiating cost. We also define a model to evaluate bids by the agents. The value of the project depends on the number of competitors, the incentives to invest, and the right-of-way costs. The right-of-way cost is approached from the perspective of a bilateral bargaining problem.
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    A risk-constrained project portfolio in centralized transmission expansion planning
    (2017) Molina, J.; Contreras, J.; Rudnick Van de Wyngard, Henry
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    Effects of Transmission Congestion on Different Incentive Policies for Renewable Energy
    (2017) Pérez de Arce Jeria, Miguel Felipe; Sauma Santis, Enzo Enrique; Contreras, J.
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    Functioning of Cx43 Hemichannels Demonstrated by Single Channel Properties
    (2003) Contreras, J.; Sáez, Juan Carlos
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    Gating and Regulation of Connexin 43 (Cx43) Hemichannels
    (2003) Contreras, J.; Sáez, Juan Carlos
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    Generalized Skew-Normal Negentropy and Its Application to Fish Condition Factor Time Series
    (2017) Arellano Valle, Reinaldo Boris; Contreras, J.; Stehlik, M.
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    Impact of high wind power penetration on transmission network expansion planning
    (INST ENGINEERING TECHNOLOGY-IET, 2012) Munoz, C.; Sauma, E.; Contreras, J.; Aguado, J.; de La Torre, S.
    Power generation from renewable sources has greatly increased in the last decade. Accordingly, the planning of power system expansions must incorporate the special features of these types of energy sources. Long-term power transmission expansion planning usually does not take these differences among energy sources into account because of the long period considered. However, modelling the special features of renewable sources may influence the optimal transmission plan. In this study, the authors propose a methodology for long-term power transmission expansion planning that incorporates the costs associated with the operation of wind power plants. In particular, the authors model the transmission expansion planning problem as a mixed-integer linear program in which the variability of the wind resource, the impact of wind power operation in the system security and the impact of wind power operation in the reserve market are incorporated. The authors illustrate the methodology using a 34-node version of the main Chilean network.
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    Impact of network payment schemes on transmission expansion planning with variable renewable generation
    (2016) Bravo, D.; Sauma Santis, Enzo Enrique; Contreras, J.; de la Torre, S.; Aguado, J.; Pozo, David
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    Impacts of network expansion on generation capacity expansion
    (IEEE, 2014) Pozo, David; Sauma Santis, Enzo Enrique; Contreras, J.
    A pessimistic three-level equilibrium model for a market-based expansion of both transmission and generation is proposed. The lower (third) level models the market outcome; the intermediate (second) level models the equilibrium in generation capacity expansion by taking into account the outcomes of the market equilibrium at the third level. The upper (first) level models the expansion of the transmission network. The second and third levels are modeled as an Equilibrium Problem with Equilibrium Constraints (EPEC) parameterized in terms of the optimal decisions of the transmission planner. This three-level hierarchy is motivated by the fact that transmission planners should consider expansions in generation that may take place, as well as the clearing of the market related to generation expansion, in order to make their decisions. At the first level, the transmission planner can take different positions with different impacts in the system because a manifold of equilibria is possible with different costs for the system. Unlike previously reported hierarchical approaches, which are implicitly formulated as optimistic, we solve the pessimistic solution of the problem (the transmission planner takes a pessimistic attitude towards the outcome of the generation expansion equilibrium). Results for a test power system are presented in order to show the efficiency and interpretations of the proposed model.
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    Multiple Equilibria in Oligopolistic Power Markets with Feed-in Tariff Incentives for Renewable Energy Generation
    (IEEE, 2015) Sauma Santis, Enzo Enrique; Pérez de Arce Jeria, Miguel Felipe; Contreras, J.
    Different policies have been implemented to incentivize the development of renewable energy generation. One of these policies is the feed-in tariff mechanism. When evaluating this policy, the typical approach is to look at the social welfare and the carbon emission reductions obtained in the optimal dispatch solution. However, in the context of oligopolistic competition in power markets, multiple market equilibria may take place. Under such a paradigm, there is generally no information about the consequences of actually occurring an equilibrium that is different than the one obtained from the optimization algorithm. Thus, a relevant question is whether the implementation of a feed-in-tariff policy decreases social welfare for all possible market equilibria or not. This paper analyzes the existence of multiple equilibria within the context of oligopolistic competition in power markets and studies the social welfare resulting in each one of them. We find that there may be equilibria for which the feed-in tariff policy increases social welfare, but also there may be equilibria for which this policy reduces social welfare. Moreover, carbon emission reductions vary from equilibrium to equilibrium, significantly varying the cost-effectiveness of the feed-in-tariff policy in reducing emissions.
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    The impact of electric vehicle charging schemes in power system expansion planning
    (2020) Manriquez, F.; Sauma Santis, Enzo Enrique; Aguado, J.; de la Torre, S.; Contreras, J.
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    Therapeutic alternatives for the treatment of type 1 hepatorenal syndrome : A Delphi technique -based consensus.
    (2016) Arab Verdugo, Juan Pablo; Claro, J. C.; Arancibia, J. P.; Contreras, J.; Gómez, F.; Muñoz, C.; Nazal, L.; Roessler Barrón, Eric; Wolff, Rodrigo; Arrese Jiménez, Marco; Benítez, C.
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    Unit Commitment With Ideal and Generic Energy Storage Units
    (2014) Pozo, David; Contreras, J.; Sauma Santis, Enzo Enrique
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    Veinte años de reparación de Ia válvula aórtica bicúspide insuficiente: a twenty year experience
    (2016) Zalaquett Sepúlveda, Ricardo; Besa, S.; Contreras, J.; Gundelach, J.; Muñoz, C.; González S M, P.
    Introducción: La Insuficiencia Aórtica (IA) excepcionalmente es susceptible de reparación. Una de estas excepciones es la Válvula Aórtica Bicúspide (VAB). Objetivo: Analizar nuestros resultados de la reparación de la VAB insuficiente. Método: Se revisó la Base de Datos para el período enero 1994 a Julio 2014. Se identificaron 29 pacientes y se revisaron las fichas clínicas y protocolos operatorios. La supervivencia se certificó en el Registro Civil e Identificación de Chile. Resultados: Todos los pacientes fueron hombres. La edad promedio fue 39,4 años (19- 61 años). Cinco pacientes presentaban una endocarditis. El ecocardiograma preoperatorio demostró IA severa en 25 casos (86%) y moderada en 4. El diámetro sis-tólico fue 44 ± 7,1 mm y el diastólico 67,8 ± 6,7 mm. La fracción de acortamiento fue 35,96 ± 5,54%. En todos los casos la VAB presentaba fusión del velo coronariano izquierdo y derecho con rafe medio; en 3, el rafe era incompleto produciéndose un cleft. En 23 casos (79%) la IA era secundaria a prolapso del velo fusionado, en 3 a perforación de velo, en 1 a un cleft y en 2 a perforación y cleft. En 23 casos (79%) se efectuó una resección triangular y en 16 (55%) se complementó con una anuloplastía. En 3 se cerró una perforación y en otros 3 se efectuó un cierre primario de cleft. En 10 casos se realizó un procedimiento asociado. En todos los casos se realizó un ecocardiograma transesofágico intra-operato-rio. En 35% no hubo insuficiencia aórtica residual y en 65% esta fue mínima o leve. No hubo mortalidad operatoria. El seguimiento se completó en el 100%. Dos pacientes (7%) fallecieron por causas no cardiacas. Siete (24%) fueron re-operados, en promedio a los 7,14 años. La media de supervivencia fue 19,3 años (IC95% 17,6-21) y la supervivencia libre de re-operación 15,8 años (IC95% 13-18,7), a 20,6 años de seguimiento. El ecocardiograma efectuado en promedio a los 4,9 años demostró una reducción del diámetro sistólico de 6,15 ± 7,2 mm (p<0,05), del diastólico de 11,26 ± 8,7 mm (p<0,05) y de la fracción de acortamiento de 1,12 ± 5,57% (p<0,33). De los 22 pacientes no reoperados, 9 no tenían IA, en 6 esta era leve (1+) y en 3 leve a moderada (2+); 4 pacientes tenían una estenosis aórtica leve. Conclusión: La reparación quirúrgica de la válvula aortica bicúspide insuficiente tiene baja mortalidad peri-operatoria y excelente supervivencia alejada. Si bien el 24% de los pacientes requirió una re-operación, esta fue tardía en la mayoría de los casos.