A virtual power plant model for time-driven power flow calculations

This paper presents the implementation of a custom-made virtual power plant model in OpenDSS. The goal is to develop a model adequate for time-driven power flow calculations in distribution systems. The virtual power plant is modeled as the aggregation of renewable generation and energy storage connected to the distribution system through an inverter. The implemented operation mode allows the virtual power plant to act as a single dispatchable generation unit. The case studies presented in the paper demonstrate that the model behaves according to the specified control algorithm and show how it can be incorporated into the solution scheme of a general parallel genetic algorithm in order to obtain the optimal day-ahead dispatch. Simulation results exhibit a clear benefit from the deployment of a virtual power plant when compared to distributed generation based only on renewable intermittent generation.Peer ReviewedPostprint (published version

Reliability analysis of distribution systems with photovoltaic generation using a power flow simulator and a parallel Monte Carlo approach

This paper presents a Monte Carlo approach for reliability assessment of distribution systems with distributed generation using parallel computing. The calculations are carried out with a royalty-free power flow simulator, OpenDSS (Open Distribution System Simulator). The procedure has been implemented in an environment in which OpenDSS is driven from MATLAB. The test system is an overhead distribution system represented by means of a three-phase model that includes protective devices. The paper details the implemented procedure, which can be applied to systems with or without distributed generation, includes an illustrative case study and summarizes the results derived from the analysis of the test system during one year. The goal is to evaluate the test system performance considering different scenarios with different level of system automation and reconfiguration, and assess the impact that distributed photovoltaic generation can have on that performance. Several reliability indices, including those related to the impact of distributed generation, are obtained for every scenario.Postprint (published version

A Solid State Transformer model for power flow calculations

This paper presents the implementation of a Solid State Transformer (SST) model in OpenDSS. The goal is to develop a SST model that could be useful for assessing the impact that the replacement of the conventional iron-and-copper transformer with the SST can have on the distribution system performance. Test distribution systems of different characteristics and size have been simulated during different time periods. The simulations have been carried out assuming voltage-dependent loads and considering that power flow through either the HV/MV substation transformer or any of the MV/LV distribution transformers can be bidirectional. Simulation results prove that a positive impact should be expected on voltages at both MV and LV levels, but the efficiency of current SST designs should be improved.Postprint (author's final draft

Comentarios sobre el informe del Secretario General de la ONU sobre el establecimiento de un Tribunal Penal Internacional para el Líbano

El proyecto para el establecimiento de un Tribunal Especial Internacional para el Líbano aprobado por la ONU el 21 de noviembre de 2006 supone la creación de un órgano jurisdiccional ad hoc de carácter internacional en un complicado momento histórico. Sin embargo, ello no debería convertirse en un obstáculo para apostar por la ratificación del Estatuto Penal de la Corte Internacional por el que se establece el único tribunal permanente para conocer de la comisión de crímenes contra la humanidad.The project for the establishment of a Special International Tribunal for Lebanon approved on November 21, 2006 by the UN implies setting up a new ad hoc International Tribunal in a crucial moment in the Middle East. Nevertheless, it should not turn into an obstacle to implement the ratification of the Rome Statute of the International Criminal Court by the states, as the only permanent court to hear about crimes against humanity

Areopagítica y su influencia en la Primera Enmienda Norteamericana. Un estudio a través de la jurisprudencia

El presente artículo trata de exponer la influencia que tuvo la conocida obra de John Milton en la redacción de la Primera Enmienda de la Constitución Norteamericana, optando para ello por el análisis de la jurisprudencia más significativa del Tribunal Supremo. Los casos seleccionados son el reflejo, a nuestro entender, de la flexibilidad de una norma, que contando con más de dos siglos de antigüedad, ha sabido adaptarse a los cambios sociales, políticos y económicos más importantes y que, en definitiva, ha sido el punto de partida de la regulación europea en este campo.The following article tries to explain the influence that John’s Milton Areopagitic had on American First Amendment, opting for the analysis of the most significant jurisprudence in the American Supreme Court. In our opinion, the selected cases are the reflection of the flexibility of that Law, that dating back to more than two centuries, it has know how to adapt itself to the most important social, political and economics changes, and definitely, it has been the starting point of the European Law in this field

Requests in films and in efl textbooks: a comparison

Research in the field of interlanguage pragmatics has shown that foreign language learners’ grammatical and pragmatic competences do not always match, this can perhaps be due to a lack of appropriate pragmatic presentation in current EFL textbooks. Hence, there seems to be a necessity of bringing authentic discourse into the classroom. One of the possibilities could be using films as input to develop classroom tasks. In this paper we analyse and compare the type, strategy and frequency of requests in both textbooks and films, in order to realise whether they provide an adequate treatment of this pragmatic issue. Results show an insufficient, unreal, decontextualised, and pragmatically inappropriate use of requesting strategies in the EFL textbooks analysed. We therefore propose using scenes from films as an authentic and motivating type of material which provides instances of real use of language and presents different requests in contextualised situations.Comunidad Valenciana GV-00-147-0

Is teaching how to suggest a good suggestion? An empirical study based on EFL learners’ accuracy and appropriateness when making suggestions

This paper focuses on the role of foreign language classroom instruction and the effectiveness of an explicit teaching of pragmatic aspects, such as the speech act of ‘suggesting’, to improve learners’ grammatical accuracy and pragmatic appropriateness. Two are the main objectives: (1) to analyse the amount and type of suggestions used by EFL learners, as well as the grammatical mistakes they make; and (2) to ascertain whether learners receiving some sort of formal instruction on appropriate speech act forms or structures will improve their linguistic and pragmatic competence.Este artículo se centra en el papel de la instrucción en el aula de lenguas extranjeras y en la efectividad que puede tener la enseñanza explícita de aspectos pragmáticos, como el acto de habla de la ‘sugerencia’, a la hora de mejorar la corrección gramatical y la adecuación pragmática de los alumnos. Dos son los objetivos principales: (1) analizar la cantidad y el tipo de sugerencias que utilizan los estudiantes de inglés y los errores gramaticales que cometen; y (2) comprobar si los alumnos que reciben algún tipo de instrucción formal sobre formas o estructuras apropiadas para actos de habla mejoran su competencia lingüística y pragmática.This study is part of a research project funded by (a) the Spanish Ministerio de Educación y Ciencia (HUM2004-04435/FILO), co-funded by FEDER, and (b) Fundació Universitat Jaume I and Caixa Castell ó-Bancaixa (P1.1B2004-34)