New mathematical model of an inverter-based generator for stability studies of microgrid Systems

A new mathematical model of a renewable generator, with a DC-AC interface, based on the concept of electrostatic machine is presented. This new model has a direct relationship between the DC and AC side. Moreover, it can be used for stability studies, taking into account the dynamics of the DC link and to find saturations and limits on the control signals.Peer ReviewedPostprint (author’s final draft

Analysis of the difficulties in reconstructing the infrastructure damaged by natural disasters in New Zealand and Puerto Rico

Once a natural disaster damages essential infrastructure services, such as roads, bridges, electric power and potable water, the priority is to restore these services as soon as possible. Under normal circumstances, the planning, design and construction of complex infrastructure projects requires an extended period of time that in many cases lasts for years. The reconstruction of essential services after a disaster is complex not only because the amount of time that can be devoted to planning is extremely limited, but also because government agencies and their officials are under public scrutiny. The press and political institutions frequently criticize thereaction time and decisions of public officials, which increases the complexity of the projects. This article uses a five-dimensional project management model (5DPM) to identify and manage the sources of complexity in emergency projects. The article describes the sources of complexity in reconstruction projects after natural disasters hit the islands of New Zealand and Puerto Rico causing great devastation. The natural disasters analyzed in this article are the earthquakes of 2010 and 2011 in New Zealand and the hurricanes Irma and Maria in 2017 in Puerto Rico. The islands, due to their geographical location, faced similar challenges in terms of the shortage of workers, and materials and equipment for reconstruction, which had to be imported. The shortage negatively impacted the response time to the emergency, the perception of the press, and public opinion about the proper handling of the emergencies. The article analyzes the sources of complexity in the reconstruction of the damaged infrastructure and concludes that the sociopolitical context is often the most complex dimension when reconstruction projects are carried out in an expeditious manner

Estudio de microgrids con interfases de convertidores de DC/AC

Este artículo presenta un estudio de Microgrids con interfases de convertidores DC/AC. El artículo muestra los modos de operación de las Microgrids, además implementa un modelo de pequeña señal para el modo de operación aislado que permite estudiar la estabilidad del sistema. Finalmente se muestra el funcionamiento de la Microgrid en ambos modos de operación.Peer ReviewedPostprint (published version

Network for the Large-Scale Integration of Renewable Energies in Electrical Systems (RIBIERSE-CYTED, 723RT0150): Results for 2023

The RIBIERSE-CYTED network, i.e., the network for the large-scale integration of renewable energies in electrical systems (723RT0150) (2023-2026) is a hub for researchers and technologists belonging to Ibero-American universities, companies, and local administrations. This network promotes cross-training, mobility between centers, and the dissemination and implementation of technical and training activities aimed at analyzing and developing opportunities for the maximal integration of renewable resources, seeking a more sustainable energy model while allowing for the increased use of renewable resources and electric mobility (e-mobility)

Associated factors for mortality in a COVID-19 colombian cohort : is the third wave relevant when Mu variant was predominant epidemiologically?

Q1Q1Pacientes con COVID-19Objectives: To evaluate the association between Colombia's third wave when the Mu variant was predominant epidemiologically (until 75%) in Colombia and COVID-19 all-cause in-hospital mortality. Methods: In this retrospective cohort, we included hospitalized patients ≥18 years with SARS-CoV-2 infection between March 2020 to September 2021 in ten hospitals from three cities in Colombia. Description analysis, survival, and multivariate Cox regression analyses were performed to evaluate the association between the third epidemic wave and in-hospital mortality. Results: A total of 25,371 patients were included. The age-stratified time-to-mortality curves showed differences according to epidemic waves in patients ≥75 years (log-rank test p = 0.012). In the multivariate Cox analysis, the third wave was not associated with increased mortality relative to the first wave (aHR 0.95; 95%CI 0.84–1.08), but there was an interaction between age ≥75 years and the third wave finding a lower HR for mortality (aHR 0.56, 95%CI 0.36–0.86). Conclusions: We did not find an increase in in-hospital mortality during the third epidemic wave in which the Mu variant was predominant in Colombia. The reduced hazard in mortality in patients ≥75 years hospitalized in the third wave could be explained by the high coverage of SARS-CoV-2 vaccination in this population and patients with underlying conditions.https://orcid.org/0000-0003-1833-1599https://orcid.org/0000-0001-5363-5729https://orcid.org/0000-0001-6964-2229https://orcid.org/0000-0003-3975-2835https://orcid.org/0000-0001-9441-4375Revista Internacional - IndexadaA1N

Transient stability analysis of inverter-interfaced distributed generators in a microgrid system

In this paper works with no-lineal tool and computer simulations, phase-plane trajectory analysis and method of Lyapunov for evaluate the limits of the small signal models and suggest to utilize models that can permit the analysis of the system when subjected to a severe transient disturbance.Peer Reviewe

Transient stability analysis of inverter-interfaced distributed generators in a microgrid system

In this paper works with no-lineal tool and computer simulations, phase-plane trajectory analysis and method of Lyapunov for evaluate the limits of the small signal models and suggest to utilize models that can permit the analysis of the system when subjected to a severe transient disturbance.Peer ReviewedPostprint (published version

Transient stability analysis of inverter-interfaced distributed generators in a microgrid system

In this paper works with no-lineal tool and computer simulations, phase-plane trajectory analysis and method of Lyapunov for evaluate the limits of the small signal models and suggest to utilize models that can permit the analysis of the system when subjected to a severe transient disturbance.Peer Reviewe

Modelling the formation of dense cold clouds

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN038680 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

New mathematical model of an inverter-based generator for stability studies of microgrid Systems

A new mathematical model of a renewable generator, with a DC-AC interface, based on the concept of electrostatic machine is presented. This new model has a direct relationship between the DC and AC side. Moreover, it can be used for stability studies, taking into account the dynamics of the DC link and to find saturations and limits on the control signals.Peer Reviewe