Browsing by Author "Watts Casimis, David Eduardo"

Now showing 1 - 6 of 6
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    Critical transitions analysis in self-organized power systems by OPA
    (IEEE, 2016) Ren, Hui; Chen, Qunjie; Wang, Fei; Watts Casimis, David Eduardo; Sun, Chenjung
    Understanding the mechanism of large scale outages is the precondition for designing of an effective prevention scheme. Complex system study shows that sudden transitions of the system from one regime to another may happen due to the nonlinear interaction among consisting components. Power systems are good examples of complex systems, and previous research shows that their critical transitions can be observed and predicted by statistical measures. These critical transitions include voltage collapse and system's entering a higher stress level from a long-term evolutional perspective. This paper continues the analysis of critical transitions in self-organized power system by Oak-PSERC-Alaska (OPA) model, a well-accepted model for the study of cascading blackouts from long-term perspective. Based on the self-organization mechanism designed in OPA, the mechanism of critical transition of power system entering a critical state is explained. The effects of local reliability on the transition is analyzed by comparing different cases. Time series of fractional load-shedding and fractional line loading are constructed and the performance of early warning of these two time series are discussed. The proposed research provide more insights on the mechanism of large blackouts, and easily available early warning signals, which are possible to implement as early warning of large catastrophic power system outage. Moreover, the fact that our research is conducted from a long-term point of view enables it to serve as a planning-assistant tool for a future power system with higher resilience.
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    High energy costs in insular energy systems and the potential for integrating innovative renewable solutions: The case of Chile
    (2024) Villarroel Labraña, Nicolás Ignacio; Watts Casimis, David Eduardo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Los sistemas energéticos insulares son fundamentales para una transición energética eficiente debido a sus características geográficas y estructurales y a su dependencia de los combustibles fósiles. La literatura indica que las energías renovables pueden mitigar los elevados costes de explotación y la dependencia de los combustibles fósiles. Sin embargo, los sistemas insulares de los países en desarrollo se enfrentan a retos políticos, técnicos y económicos específicos que requieren un estudio más profundo. Este artículo analiza exhaustivamente los sistemas energéticos insulares chilenos, ofreciendo recomendaciones para aumentar eficientemente la penetración de la generación renovable. Se realiza un análisis detallado del perfil de consumo eléctrico, las políticas actuales y la operación del sistema. Además, se investiga la baja penetración de las energías renovables en estos sistemas, levantando barreras como las limitaciones técnicas, la obstrucción política y la percepción de riesgo en las inversiones. Se presentan recomendaciones políticas para superar estos obstáculos, promoviendo la integración efectiva de las energías renovables en los sistemas insulares de Chile y a nivel global. Las soluciones propuestas incluyen el modelo de negocio de Build-Operate-Transfer (BOT), el modelo de negocio Third-Party-Owned (TPO), la fijación de precios mediante Long-Run Incremental Cost (LRIC) y la concordancia regulatoria. La investigación destaca que, aunque las energías renovables pueden reducir los costes de explotación, las barreras a la integración son el principal reto para aumentar la penetración de la generación renovable. Este estudio aporta valiosas ideas para tomadores de decisión políticos, investigadores e inversionistas interesados en la viabilidad de la generación renovable en sistemas insulares.
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    Long-Run Energy and Emissions Modeling in Chile: Scenario Assessment using MESSAGE
    (2012) Watts Casimis, David Eduardo; Martinez Aranza, Victor Julio
    The evolution of Chile's energy matrix into a more sustainable system with high levels of energy adequacy and security in the long term brings with it important challenges and could signify a paradigm change in the manner in which the system is planned and managed. Long-term energy planning, forgotten in Chile due to the control of the markets, is now fundamental for studying changes in the future national energy supply and its emissions. This article contributes by developing an energy model of the main national system in MESSAGE and evaluating the effects of the scenarios that dominate national discussions; including large amounts of hydro, nuclear and wind energy. We find that using part of the country's hydro power potential is fundamental to replace carbon without imposing higher costs in the economy. However, the use of large amounts of low marginal cost energy (hydro, nuclear, wind, etc.) creates important drops in the price of energy which could compromise the sustainability of these scenarios in the marginal pricing framework that is utilized today.
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    Network motif as an indicator for cascading outages due to the decrease of connectivity
    (IEEE, 2017) Chen, Qunjie; Ren, Hui; Sun, Chenjung; Mi, Zengqiang; Watts Casimis, David Eduardo
    Complex network study pointed out that, between the macro level and the micro level, there still exist abundant various dimensions addressed as subgraph, including motifs, cliques, cores... The structural property of these subgraphs plays an import role for the robustness in the function of the system. In this paper, the network motif existing in different IEEE test systems and real power grids are identified, and the consistency between the structural feature of motif and power system design for reliable power supply is revealed. By incorporating the transmission line margin into the procedure of finding significant motifs, the risk of cascading overloads due to insufficient transmission capacity and the decrease of connectivity of the power network is reflected by the occurrence of certain motifs in the power network. Through the simulation of cascading failures along the continuous increase of load demand and random line failures, different phases in the evolution of cascading failures are defined, and the patterns in the occurrence of motifs corresponded to different phases are identified. The performance of network motifs as a warning signal for higher risk of large outages is also tested under continuous line/node removal scenario. Test results show that the occurrence of motifs can be a good supplement to the EENS to describe the risk of outages.
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    The Spatial Statistics of Self-organized in Power System
    (IEEE, 2018) Jiang, Nannan; Ren, Hui; Watts Casimis, David Eduardo; Liu, Ying; Lu, Haitao; Tian, Jiefu
    Self-organized criticality (SOC) is one of explanation accepted so far on the mechanism of large blackouts. Based on the previous study on the temporal statistics of self-organized power system, the spatial statistics of the power system along its evolution is analyzed for better understanding of the mechanism of large blackouts. The conventional sensitivity method, Power Transfer Distribution Factor (PTDF), is used as the spatial weight matrix for the calculation of spatial auto correlation by Moran's I. An equivalent transmission capacity is defined as the observation. Besides Moran's I, mean, standard deviation and Entropy of equivalent transmission capacity are also provided for a better understanding of the effect of the evolution of transmission capacity on the system entering SOC, when large blackouts are of bigger possibility. IEEE -118 system is taken as a test system for the analysis. The analysis shows that spatial auto correlation by Moran's I is better for describing the heterogeneity of the power system and is a prospective candidate for the early warning of power system entering SOC.
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    The temporal-spatial stochastic model of plug-in hybrid electric vehicles
    (IEEE, 2017) Jiang, He; Ren, Hui; Sun, Chenjun; Watts Casimis, David Eduardo
    Plug-in hybrid electric vehicles (PHEVs) are considered as one of the most complicated loads/power sources because of the temporal and spatial stochastic features compared to other controllable loads. Most of the studies on the modelling of PHEVs are based on the travel survey or only considers their temporal stochastics. However, with the development of charging stations and commercial passenger cars, or for specific study, such as voltage quality, the spatial stochastics cannot be neglected. A comprehensive simulation model considering the temporal and spatial stochastics is then needed. In this paper, we build a stochastic model of PHEV, considering PHEV's temporal in arrival time, departure time and driving time and spatial randomness in the charging and discharging locations. IEEE-13 is taken as a test system and the effect of PHEVs on the daily load curve is investigated. The model is going to be a good compliment for the travel survey bases study.