Browsing by Author "Pozo, David"
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- ItemA convex chance-constrained model for reactive power planning(2015) Lopez, Julio; Pozo, David; Contreras, Javier; Mantovani, J. R. S.
- ItemA Three-Level Static MILP Model for Generation and Transmission Expansion Planning(2013) Pozo, David; Sauma Santis, Enzo Enrique; Contreras, Javier
- ItemAdmission planning in health care : stochastic and hierarchical approaches(2020) Germán, Ana Batista; Vera Andreo, Jorge; Pozo, David; Pontificia Universidad Católica de Chile. Escuela de IngenieríaEl sistema de salud es una industria de servicios que requiere planificación de calidad debido a la relevancia en sus operaciones. En particular, los hospitales públicos enfrentan presión constante para ser eficientes. Un proceso clave que gestiona las operaciones hospitalarias es la planificación de admisiones, que tiene como objetivo garantizar acceso oportuno y uso eficiente de los recursos. Sin embargo, varias fuentes de incertidumbre y limitaciones de recursos desafían el logro de esos objetivos. Además, similar a muchas industrias, las decisiones de largo plazo del hospital se basan en planes agregados que deben cumplirse en el corto plazo, el cual está sujeto a incertidumbre. Dado que no se garantiza coordinación temporal, pueden surgir varias inconsistencias, como tiempos de espera innecesarios, rechazos e incluso muerte prematura de los pacientes. Esta tesis evalúa el problema de consistencia temporal en el problema de planificación de admisiones, el cual está sujeto a incertidumbre y limitado por la capacidad de camas. El problema radica en cómo desarrollar un plan táctico que considere el impacto de las decisiones operativas mientras que garantice su viabilidad. El objetivo principal es modelar y resolver un proceso jerárquico de toma de decisiones que integre los niveles táctico y operativo para mejorar la calidad del servicio y el uso eficiente de los recursos. La investigación contribuye a proporcionar marcos de decisión efectivos para resolver el problema de planificación de admisiones. Consideramos métodos de optimización bajo incertidumbre en múltiples etapas para mejorar la consistencia y coordinación de la planificación. Se desarrolla un enfoque bi-objetivo estocástico en dos etapas para estudiar las decisiones de asignación, considerando incertidumbre de la demanda y disponibilidad de camas y evaluar el trade-off entre la perspectiva del paciente y la del hospital. Dado que el acceso a información es limitado, también se propone un enfoque de optimización robusta distribucional adaptativa para estudiar decisiones de asignación y programación. Se considera información parcial distribucional del tiempo de estadía, modelado a través de una formulación mejorada para restricciones de tipo de tiempo de servicio. El enfoque permite evaluar la relación entre robustez y consistencia. Mediante extensos estudios numéricos y validaciones con datos reales, demostramos que se obtiene una planificación eficiente adoptando un marco de decisión estocástico jerárquico. El marco es capaz de minimizar las inconsistencias implicadas en la planificación de admisión. Se proporcionan lineamientos de gestión para planificación táctica-operativa.
- ItemBasic theoretical foundations and insights on bilevel models and their applications to power systems(2017) Pozo, David; Sauma Santis, Enzo Enrique; Contreras, Javier
- ItemCan cross-border transmission expansion lead to fair and stable cooperation? Northeast Asia case analysis(2019) Churkin, Andrey; Pozo, David; Bialek, Janusz; Korgin, Nikolay; Sauma Santis, Enzo Enrique
- ItemClimate-aware generation and transmission expansion planning: A three-stage robust optimization approach(2021) Moreira, Alexandre; Pozo, David; Street, Alexandre; Sauma Santis, Enzo Enrique; Strbac, GoranIn this paper, we propose a three-stage robust generation and transmission expansion planning model considering generation profiles of renewable energy sources (RES) affected by different long-term climate states. Essentially, we extend the broadly utilized two-stage modeling approach to properly consider partial information of climate states with conditional short-term scenarios of RES output and outages. The proposed model is formulated as a five-level optimization problem. The first level determines the optimal generation and transmission expansion plan under uncertainty in climate conditions, RES generation, and contingencies. Given the selected expansion plan, the second level identifies the most severe climate state. Following the decision-information hierarchy, in the third level, the system operator optimizes the generation schedule of energy and reserves under perfect information of the climate state, but yet under uncertainty in the RES generation and contingencies. Then, the fourth level identifies the worst-case combination of contingency and conditional short-term RES generation adjusted to the current climate condition. Finally, the fifth level determines the optimal redispatch of reserves to react against the worst-case RES generation and contingency scenario considering the uppermost decisions. Within this multi-level structure, the optimal investment plan considers a more realistic decision setting, where system operators adapt RES forecasts based on the observed climate conditions before planning the operational schedule. To solve the problem, a variant of the nested column-and-constraint-generation algorithm is proposed with global-optimality guarantee in a finite number of steps. A case study based on the Chilean system illustrates the applicability of the model in a realistic network.
- ItemEnergy storage and transmission expansion planning : substitutes or complements?(2018) Bustos, Carlos; Sauma Santis, Enzo Enrique; De la Torre, Sebastián; Aguado, José A.; Contreras, Javier; Pozo, David
- ItemEnhancing the Stability of Coalitions in Cross-Border Transmission Expansion Planning(2022) Churkin, Andrey; Sauma Santis, Enzo Enrique; Pozo, David; Bialek, Janusz; Korgin, NikolayCooperative Game Theory has recently attracted attention in power systems research as a tool for expansion planning analysis. However, this analysis is usually performed in an ex-post manner, i.e., planning and operation decisions are separated from the allocation mechanisms themselves. The existing paradigm implies selecting an allocation rule (say, the Shapley value) to share the value of cooperation and verifying its rationality (e.g., by checking the Core of the cooperative game). Additional metrics of coalitional stability are omitted. Such an ex-post approach could lead to coalitional stability issues, which may hamper the establishment of cooperation. For example, there could be a severe imbalance in players' positions, and the contribution of some players could be underestimated in the grand coalition. This paper proposes a bilevel optimization framework for explicitly incorporating Cooperative Game Theory principles into transmission expansion planning problems. Using a simple 4-system case study and a real-world case of cross-border power interconnections in Northeast Asia, we demonstrate that it is possible to make planning decisions in an anticipatory manner subject to the stability of coalitions. The identified expansion plans with enhanced coalitional stability indicate the ways of making parties more equally involved in electricity trading. Finally, we discuss the applicability of the bilevel TEP model, the properties of resulting cooperative games, and the compromise between coalitional stability and economic efficiency in transmission expansion planning.
- ItemIf you build it, he will come : anticipative power transmission planning(2013) Pozo, David; Contreras, Javier; Sauma Santis, Enzo Enrique
- ItemImpact 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
- ItemImpacts 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.
- ItemManipulability of Cost and Benefit Allocation in Cross-border Electrical Interconnection Projects(IEEE, 2019) Churkin, A.; Pozo, David; Bialek, J.; Korgin, N.; Sauma Santis, Enzo EnriqueCross-border electrical interconnection projects are getting more attention all over the world. In this context, cost-benefit allocation is especially important due to the need for fair sharing of power trading benefits among the countries as well as allocating the investments in capital-intensive power lines. One convenient way of dealing with these issues is using cooperative game theory. However, even fair allocation methods, such as the Shapley value, do not guarantee the stability of negotiations on cross-border interconnection projects. The result of the allocation process strongly depends on the individual system's data provided by each party involved. In this regard, the parties could have incentives to strategically provide data that would benefit themselves in the cost-benefit allocation process, potentially hindering the stability of the coalition. In this paper, we address the negotiation stability issues in terms of players strategic behavior and manipulability of cost-benefit allocation rules.
- ItemMulti-objective admission planning problem : a two-stage stochastic approach(2020) Germán, Ana Batista; Vera Andreo, Jorge; Pozo, David
- ItemPower system expansion planning under global and local emission mitigation policies(2019) Quiroga Vergara, Daniela Isabel; Sauma Santis, Enzo Enrique; Pozo, DavidThis work analyzes the impacts on the power system expansion planning of implementing CO2 and local pollutant emission taxes under five different policy-relevant scenarios. To do this, we have formulated and implemented an optimization model based on a mixed-integer linear program, which determines the optimal expansion plan considering the installation of both large-scale power plants and renewable-based distributed generation. An important characteristic of the proposed model is that it includes a detailed formulation of the power system. Moreover, differently than existing literature, special attention is given to the analysis of the spatial-temporal distributive effects of pollutant taxes, considering both global and local pollutant emissions. The method is applied to the main Chilean power system. Our results indicate that global and local pollutant taxes significantly impact both planning and operational decisions in the power system. In particular, pollutant taxes may have significant spatial distributive effects, as shown in the analysis of 13 regions of Chile, leading to damages in some specific regions while relatively benefiting others. Our results also show that the availability of renewable energy capacity may improve the effectiveness of pollutant taxes. Particularly, adding 1.5 GW of hydro capacity to the Chilean system allows avoiding around 32 GWh of fossil fuel generation per year, saving more than 1.5 billion US$ in the 10-year horizon considered. The proposed method and qualitative results are sufficiently generic to apply to any other jurisdiction.
- ItemReliable Renewable Generation and Transmission Expansion Planning: Co-Optimizing System's Resources for Meeting Renewable Targets(2017) Moreira, Alexandre; Pozo, David; Street, Alexandre; Sauma Santis, Enzo Enrique
- ItemReview of Cooperative Game Theory applications in power system expansion planning(2021) Churkin, Andrey; Bialek, Janusz; Pozo, David; Sauma Santis, Enzo Enrique; Korgin, NikolayIn recent years, mechanisms of cooperation in power systems have attracted increasing attention from academia and industry. Such mechanisms require sharing the benefits of cooperation among participants based on some rational and obvious principles. In this regard, Cooperative Game Theory (CGT) provides a rich theoretical background for the analysis of projects where participants (called players) can make collective actions to obtain mutual benefits. CGT concepts not only solve the subsequent allocation problems but also reveal the bargaining power of players and estimate the stability of cooperation over a project. In this paper, we aim to classify and promote CGT applications in power systems. While covering a broad range of applications (such as cost and benefit allocation, transmission pricing, projects ranking, allocation of power losses), we pay particular attention to power system expansion planning. We first introduce an illustrative example of cooperation in transmission expansion planning and discuss the applicability of CGT solution concepts. To give a complete picture of the state of the art, we perform a citation network analysis of more than 3000 related studies from 1996 to 2020. Exploiting the graph layout and modularity algorithms, we identify the main research communities and highlight their contributions. We found that significant progress has been achieved in developing mechanisms of cooperation in power systems based on CGT solution concepts. However, several challenges and limitations of these concepts still have to be overcome, such as scalability, nonconvexity of cooperative games, coalitions formation assumption, ex-post game-theoretic analysis, incompleteness and manipulability of information. The overview presented in this paper and the citation network analysis performed can help scientists and engineers in comprehending the CGT solution concepts, discovering novel applications for power systems, and contributing to this promising multidisciplinary research direction.
- ItemRisk-constrained dynamic energy allocation for a wind power producer(2014) González, Virginia; Pozo, David; Contreras, Javier
- ItemRobust unit commitment with n-1 security criteria(2016) Gourtani, Arash; Xu, Huifu; Pozo, David; Nguyen, Tri-Dung
- ItemStochastic Time-of-Use-Type Constraints for Uninterruptible Services(IEEE, 2020) Batista German, Ana; Pozo, David; Vera Andreo, JorgeIn this paper, a mixed integer linear formulation for problems considering time-of-use-type constraints for uninterruptible services is presented. This paper is motivated by demand response (DR) problems in power systems, in which certain devices must remain online once they are switched on, along with a certain number of periods. Classically, this kind of constraints are modeled as a summation over a rolling time windows. This makes it difficult to consider this time-of-use parameter as uncertain. We propose an alternative formulation in which the time of use is on the right-hand side of a constraint instead on the limit of a summation. This allows applying existing stochastic optimization methodologies easily. An illustrative model for the optimal allocation of an uninterruptible load for the DR problem supports the proposed formulation.
- ItemUnit Commitment With Ideal and Generic Energy Storage Units(2014) Pozo, David; Contreras, J.; Sauma Santis, Enzo Enrique