PI and LQR controllers for Frequency Regulation including Wind Generation

The increasing use of renewable technologies such as wind turbines in power systems may require the contribution of these new sources into grid ancillary services, such as Load Frequency Control. Hence, this work dealt with the performance comparison of two traditional control structures, PI and LQR, for secondary regulation of Load Frequency Control with the participation of variable-speed wind turbines. For this purpose, the doubly-fed induction generator wind turbine was modeled with additional control loops for emulation of the inertial response of conventional machines for frequency regulation tasks. Performance of proposed strategies was verified through simulation in a benchmark adapted from the WSCC 3 machines 9-bus test system. Results showed overall superior performance for LQR controller, although requiring more strenuous control effort from conventional units than PI control

From the electric machine to radiology in Colombia

Reinaba un olor extraño. Una especie de ozono diluido en la atmósfera. Entre las ventanas cubiertas de negro la cabina dividía el laboratorio en dos partes desiguales. Se distinguían aparatos de física, cristales cóncavos, tableros de interruptores, instrumentos para medir, una caja semejante a un aparato fotográfico sobre un chasis de ruedas, y diapositivas en cristal alineadas en paredes hasta el punto de que no se sabía si uno se hallaba en el taller de un fotógrafo, en una cámara oscura, en el taller de un inventor, o en la oficina de técnica de hechicería.There was a strange smell. A kind of ozone diluted in the atmosphere. Between the black-covered windows the cabin divided the laboratory into two unequal parts. There were physics apparatuses, concave glass, switch panels, measuring instruments, a box resembling a photographic apparatus on a wheeled chassis, and glass slides lined up on walls to the point that one could not tell if one was in them. a photographer's workshop, in a camera obscura, in an inventor's workshop, or in the office of sorcery technique

De la máquina eléctrica a la radiología en Colombia

ResumenReinaba un olor extraño. Una especie de ozono diluido en la atmósfera. Entre las ventanas cubiertas de negro la cabina dividía el laboratorio en dos partes desiguales. Se distinguían aparatos de física, cristales cóncavos,tableros de interruptores, instrumentos para medir, una caja semejaníe a un aéaraío foíográfáco sobre un chasás de ruedas, y diapositivas en cristal alineadas en paredes hasía el éunío de que no se sabía sá uno se hallaba en eltaller de un fotógrafo, en una cámara oscura, en el taller de un ánveníor, o en la ofácána de íécnáca de hechácería

Evaluación de la gestión administrativa de la asociación de juntas de acción comunal (ASOCOMUNAL) Chigorodó. Periodo 2017 al 2020.

Se realizó un estudio etnográfico con el que se pretende identificar desde la percepción de los dignatarios, la Gestión Administrativa de la asociación de juntas de acción comunal – ASOCOMUNAL – Chigorodó (Antioquia), en el período 2017,2018, 2019 y 2020. Para alcanzar este fin, se tuvo como punto de partida un estudio de antecedentes y una contextualización general que permitió, posteriormente, detallar como ha sido la gestión administrativa de este organismo comunal de segundo grado, en sus cuatro componentes: Planeación, organización, dirección y control. Para este proyecto de grado se utilizó el método descriptivo con enfoque de investigación mixto, cuanti-cualitativo, para la obtención y el procesamiento de los resultados, se aplicó un instrumento de entrevistas semiestructuradas con su respectivo análisis. Donde se entrevistaron 15 dignatarios de la junta directiva. Además se realizó un análisis documental principalmente del libro de actas y tesorería. El análisis de la información nos arrojó detalles en la gestión administrativa como fueron: En su planeación se evidencia que tienen plan de trabajo, pero a corto plazo sin tener una visión a largo plazo. En organización están bien estructurados organizacionalmente y tienen funciones específicas bien establecidas, pero su bajo nivel de escolaridad y desconocimiento de sus funciones limita la organización de sus recursos humanos, físicos y financieros. En su dirección a pesar de respetar los niveles jerárquicos se presentan inconvenientes de género y generacional. En el componente de control lo vienen realizando constantemente pero muy limitado ya que no cuentan con indicadores de gestión. Finalmente con el análisis de la gestión administrativa se pudo obtener un diagnostico el cual nos sirvió para realizar una propuesta de mejoramiento administrativo, sustentándose en las debilidades encontradas e identificando las acciones de mejora especialmente en la capacitación, modernización tecnológica, mejora en sus procesos y motivación de sus integrantes.An ethnographic study was carried out with which it is intended to identify, from the perception of the dignitaries, the Administrative Management of the association of community action boards - ASOCOMUNAL - Chigorodó (Antioquia), in the period 2017, 2018, 2019 and 2020. To achieve for this purpose, it had as its starting point a background study and a general contextualization that subsequently received a detailed description of how the administrative management of this second-degree communal body has been, in its four components: Planning, organization, direction and control. For this degree project, the descriptive method with a mixed, quantitative-qualitative research approach was used to obtain and process the results, an instrument of semi-structured interviews with their respective analysis was applied. Where 15 dignitaries of the board of directors were interviewed. In addition, a documentary analysis was carried out mainly of the minute book and treasury. The analysis of the information gave us details in the administrative management such as: In their planning it is evident that they have a work plan, but in the short term without having a long-term vision. In organization they are well structured organizationally and have well-established specific functions, but their low level of education and ignorance of their functions limits the organization of their human, physical and financial resources. In his direction, despite respecting the hierarchical levels, there are gender and generational disadvantages. In the control component they have been doing it constantly but very limited since they do not have management indicators. Finally, with the analysis of administrative management, it was possible to obtain a diagnosis which helped us to make a proposal for administrative improvement, based on the weaknesses found and identifying improvement actions, especially in training, technological modernization, improvement in its processes and motivation. Of its members

Bienvenida a los migrantes a una Europa sin fronteras: los briófitos muestran el camino a seguir

La reconstrucción de la historia cuaternaria de los briófitos europeos ha supuesto un reto durante mucho tiempo, ya que, a excepción de restos macroscópicos preservados en turberas, el registro fósil es excepcionalmente escaso en comparación con el de plantas vasculares. Análisis de coalescencia revelaron que el ensamblaje postglacial de las comunidades de briófitos europeos es compleja e incluye múltiples orígenes, contrastando con el modelo clásico que apunta al predominio de una migración hacia el norte desde refugios mediterráneos. Una parte significativa de la brioflora de Europa preexistente antes de la Edad del Hielo fue reforzada por migrantes alóctonos. Sin embargo, la Franja Atlántica europea fue principalmente colonizada por especies tropicales. Se postula que para el elemento florístico oceánico de briófitos, Macaronesia ha jugado un papel como ‘stepping-stone’ hacia Europa, un paso imprescindible para que especies tropicales puedan preadaptarse bajo los típicos regímenes climáticos suaves insulares, antes de establecerse en regiones templadas.Reconstructing the Quaternary history of European bryophytes has long been challenging because, except for macro-remains preserved in peat, the fossil record is extremely poor as compared to vascular plants. Coalescent simulations revealed that the postglacial assembly of European bryophytes involves a complex history from multiple sources, contrasting with the prevailing model of northwards species migration from Mediterranean refugia. A scenario of extra-European postglacial recolonization clearly emerged as dominant. A bulk of the bryoflora that pre-existed in Europe before the Ice Age was reinforced by allochthonous migrants. The Atlantic European fringe was, in contrast, de novo colonized by species primarily distributed across tropical areas. We hypothesize that, for the particular case of the oceanic bryophyte floristic element, the Macaronesian islands represented a mandatory stepping-stone situated midway between the tropics and Europe due to the necessity for tropical species to pre-adapt under insular warm-temperate conditions before they successfully establish in temperate regions

Load Frequency Control of a Multi-area Power System Incorporating Variable-speed Wind Turbines

Abstract: The increasing use of renewable technologies in power generation may require its participation on ancillary services like frequency regulation. For the specific case of wind sources, this may lead to participation in frequency control loops. This paper focuses on the simulation of the performance of the LFC scheme for a multi-area power system, with participation of DFIG turbines in the frequency control loops, through the synthetic inertia method

Trees as habitat islands: temporal variation in alpha and beta diversity in epiphytic laurel forest bryophyte communities

Aim: Trees represent striking examples of habitat islands, with various degrees of spatial isolation and evolving properties during their life cycle. Here, we investigate whether changes in habitat conditions, dispersal limitations or competition cause variation in patterns of epiphytic species richness and turnover. Location: Madeira island. Taxon: Bryophytes. Methods: Using linear mixed effect models, we test whether species richness exhi bits a monotonic or hump-shaped relationship with time. Two groups of host-tree species, late- and early-successional, were considered. We further identify the mechanisms explaining the observed variation in species composition by dividing beta diversity into its nestedness (bsne) and turnover (bsim) components and correlat ing them with tree age and geographical distance among trees. Results: The best-fit models all included tree age (T), but its quadratic term (T2 ) and tree height (H, here a surrogate of area) were not systematically included. bsim, but not bsne, correlated with host-tree age, and both bsim and bsne correlated with geo graphical distance. Main conclusions: Tree age was consistently included in all of the best-fit models, reflecting the progressive increase in epiphyte bryophyte species richness through time. The limited contribution of T2 and H to the best models suggests that compe tition for space is not a key factor on mature trees. The correlation of bsim, but not bsne, with host-tree age, and of bsim and bsne with distance among trees, suggests that variation in species composition is caused by (1) temporal community shifts due to allogenic drivers and (2) dispersal limitations, which are reflected by the higher similarity of the epiphyte communities on clustered trees rather than by an increasing probability of colonization with tree age. Since actual ancient laurel for ests may no longer exist in Madeira, the conservation of clusters of late-succes sional trees, enhancing connectivity at small spatial scales, is of utmost importance for the conservation and recovery of the unique laurel forest epiphytic flora.info:eu-repo/semantics/publishedVersio

Actividad antioxidante y antimicrobial de los volátiles de cuatro variedades de albahacas cultivadas en el departamento del Tolima

Se determinó la actividad antioxidante de los hidrodestilados de cuatro variedades de Ocimum colectadas en Ibagué, evaluando su capacidad atrapadora del radical DPPH (CARL) y el poder inhibitorio de peroxidación lipídica. Bioprospección de estos extractos naturales de la región se aumentó evaluando su potencial antimicrobial frente a bacterias gram positivas, gram negativas y una levadura. Todos los aceites esenciales mostraron fuerte actividad antioxidante (CARL) comparable a la del tocoferol y actividad antimicrobial frente a Candida albicans, principalmente de las albahacas crespa morada y canela.The antioxidant activity of the hydrodistilleds of four Ocimum varieties growing in Ibagué, was determined by means of both, DPPH radical scavenging activity (FRSA) and inhibition of lipid peroxidation, methods. Bioprospection research with regard these regional natural extracts was increased through the evaluation of the antimicrobial potential against Gram positives,Gram negatives bacteria and a yeast. All the essential oils showed strong antioxidant activity (FRSA) comparable with that of ¿-tocopherol and antimicrobial activity against Candida albicans, mainly exhibited by purple rufle and cinnamon basils

The taxonomic status and the geographical relationships of the Macaronesian endemic moss Fissidens luisieri (Fissidentaceae) based on DNA sequence data

Copyright © 2009 by The American Bryological and Lichenological Society, Inc.The taxonomic identity and the geographical relationships of the Macaronesian endemic moss Fissidens luisieri have been studied using the chloroplast trnGUCC intron, the spacer between trnM and trnV, together with the trnV intron and ITS1 and ITS2 sequences. A comparison of F. luisieri with the most closely related species, F. serrulatus, from the same geographical areas reveals that the distribution pattern of F. serrulatus and F. luisieri, rather than their morphological differences, explains the observed differences. Therefore, we conclude that both names correspond to the same species. One of the primers for the chloroplast trnGUCC intron and both primers for the trnM–trnV region were designed for this study; they can all be widely used within bryophytes because they provide similar degrees of variability as other regions of the chloroplast genome such as the atpB–rbcL intergenic spacer

Distribution patterns of Leucodon species in Macaronesia, with special reference to the Canary Islands

Copyright © 2009 Adac. Tous droits réservés.The genus Leucodon is represented in Macaronesia by three species, L. sciuroides, L. canariensis and L. treleasei, the latter two being endemic to this region. An analysis of distribution, frequency and habitats for all three species in this region shows singular patterns for each species, mainly related to habitat conservation and type of habitat. Leucodon canariensis is the most restricted species as regards habitat conditions, with a confirmed presence only on Madeira and the Canary Islands, although more abundant in the latter. Leucodon treleasei exhibits the widest habitat amplitude, especially on Madeira, and it is present in all three northern archipelagos. Leucodon sciuroides is the most tolerant species to aridity and is mainly found on Madeira and the Canary Islands, although its occurrence was confirmed in all the Macaronesian archipelagos