Geometric Algebra in Nonsinusoidal Power Systems: A Case of Study for Passive Compensation

New-generation power networks, such as microgrids, are being affected by the proliferation of nonlinear electronic systems, resulting in harmonic disturbances both in voltage and current that affect the symmetry of the system. This paper presents a method based on the application of geometric algebra (GA) to the resolution of power flow in nonsinusoidal single-phase electrical systems for the correct determination of its components to achieve passive compensation of true quadrature current. It is demonstrated that traditional techniques based on the concepts of Budeanu, Fryze or IEEE1459 fail to determine the interaction between voltage and current and therefore, are not suitable for being used as a basis for the compensation of nonactive power components. An example is included that demonstrates the superiority of GA method and is compared to previous work where GA approaches and traditional methods have also been used

Evolutionary Algorithms for Community Detection in Continental-Scale High-Voltage Transmission Grids

Symmetry is a key concept in the study of power systems, not only because the admittance and Jacobian matrices used in power flow analysis are symmetrical, but because some previous studies have shown that in some real-world power grids there are complex symmetries. In order to investigate the topological characteristics of power grids, this paper proposes the use of evolutionary algorithms for community detection using modularity density measures on networks representing supergrids in order to discover densely connected structures. Two evolutionary approaches (generational genetic algorithm, GGA+, and modularity and improved genetic algorithm, MIGA) were applied. The results obtained in two large networks representing supergrids (European grid and North American grid) provide insights on both the structure of the supergrid and the topological differences between different regions. Numerical and graphical results show how these evolutionary approaches clearly outperform to the well-known Louvain modularity method. In particular, the average value of modularity obtained by GGA+ in the European grid was 0.815, while an average of 0.827 was reached in the North American grid. These results outperform those obtained by MIGA and Louvain methods (0.801 and 0.766 in the European grid and 0.813 and 0.798 in the North American grid, respectively)

A Hybrid Active Filter Using the Backstepping Controller for Harmonic Current Compensation

This document presents a new hybrid combination of filters using passive and active elements because of the generalization in the use of non-linear loads that generate harmonics directly affecting the symmetry of energy transmission systems that influence the functioning of the electricity grid and, consequently, the deterioration of power quality. In this context, active power filters represent one of the best solutions for improving power quality and compensating harmonic currents to get a symmetrical waveform. In addition, given the importance and occupation of the transmission network, it is necessary to control the stability of the system. Traditionally, passive filters were used to improve energy quality, but they have endured problems such as resonance, fixed remuneration, etc. In order to mitigate these problems, a hybrid HAPF active power filter is proposed combining a parallel active filter and a passive filter controlled by a backstepping algorithm strategy. This control strategy is compared with two other methods, namely the classical PI control, and the fuzzy logic control in order to verify the effectiveness and the level of symmetry of the backstepping controller proposed for the HAPF. The proposed backstepping controller inspires the notion of stability in Lyapunov’s sense. This work is carried out to improve the performance of the HAPF by the backstepping command. It perfectly compensates the harmonics according to standards. The results of simulations performed under the Matlab/Simulink environment show the efficiency and robustness of the proposed backstepping controller applied on HAPF, compared to other control methods. The HAPF with the backstepping controller shows a significant decrease in the THD harmonic distortion rate

Detection of Communities within the Multibody System Dynamics Network and Analysis of Their Relations

Multibody system dynamics is already a well developed branch of theoretical, computational and applied mechanics. Thousands of documents can be found in any of the well-known scientific databases. In this work it is demonstrated that multibody system dynamics is built of many thematic communities. Using the Elsevier’s abstract and citation database SCOPUS, a massive amount of data is collected and analyzed with the use of the open source visualization tool Gephi. The information is represented as a large set of nodes with connections to study their graphical distribution and explore geometry and symmetries. A randomized radial symmetry is found in the graphical representation of the collected information. Furthermore, the concept of modularity is used to demonstrate that community structures are present in the field of multibody system dynamics. In particular, twenty-four different thematic communities have been identified. The scientific production of each community is analyzed, which allows to predict its growing rate in the next years. The journals and conference proceedings mainly used by the authors belonging to the community as well as the cooperation between them by country are also analyzed

OpenZmeter: An Efficient Low-Cost Energy Smart Meter and Power Quality Analyzer

Power quality and energy consumption measurements support providers and energy users with solutions for acquiring and reporting information about the energy supply for residential, commercial, and industrial sectors. In particular, since the average number of electronic devices in homes increases year by year and their sensitivity is very high, it is not only important to monitor the total energy consumption, but also the quality of the power supplied. However, in practice, end-users do not have information about the energy consumption in real-time nor about the quality of the power they receive, because electric energy meters are too expensive and complex to be handled. In order to overcome these inconveniences, an innovative, open source, low-cost, precise, and reliable power and electric energy meter is presented that can be easily installed and managed by any inexperienced user at their own home in urban or rural areas. The system was validated in a real house over a period of two weeks, showing interesting results and findings which validate our proposal

Acción Tutorial entre Alumnos de Diferentes Cursos en las Asignaturas de Arquitectura de Computadores

Se presenta una experiencia de acción tutorial entre iguales llevada a cabo entre grupos cooperativos de alumnos de 4º curso de Ingeniería Informática y grupos cooperativos de 2º curso de Ingeniería Técnica en Informática de Gestión en las asignaturas de Arquitectura de Computadores. Esta experiencia que presentamos se enmarca en la filosofía del EEES y apuesta por la incorporación de nuevas dimensiones de la tutoría en el ámbito universitario: tutoría entre iguales y tutoría a través de las nuevas tecnologías. Por un lado, grupos cooperativos de 4º curso han realizado la función del compañero-tutor que trabaja de forma colaborativa con sus compañeros de 2º curso. Por otro, el proceso de tutoría se ha retroalimentado de forma sustancial a través del uso de la plataforma digital en un entorno de grupos cooperativos que disponen de su propio espacio común, foro, correo electrónico y portafolios de grupo. Este trabajo, representa también, un primer paso dentro de una experiencia de mayor envergadura: los proyectos integrados o transversales entre varias asignaturas o incluso un proyecto global a nivel de titulación y en el que, en cada curso, se va realizando una parte de este, por lo que es de gran utilidad la acción tutorial de alumnos de cursos superiores

Portafolio Digital de Grupo en Arquitectura de Computadores: Herramienta de Evaluación y Tutorización

En este trabajo se presenta una propuesta de enseñanza-aprendizaje-evaluación que combina el uso de metodologías activas como el aprendizaje cooperativo con el portafolio digital de grupo a través de una plataforma digital de apoyo a la docencia. Esta experiencia se ha llevado a cabo en las asignaturas de Arquitectura de Computadores de 4º curso de Ingeniería Informática de la Universidad de Almería. Con este cambio, se intentaba dar respuesta a la necesidad de implicar a los estudiantes de forma activa en su proceso de aprendizaje, además de desarrollar algunas competencias transversales de cara al EEES (Espacio Europeo de Educación Superior). Se resalta el uso del portafolio digital de grupo, como método de aprendizaje y evaluación que permite unir y coordinar un conjunto de evidencias para emitir una valoración lo más ajustada a la realidad, que es difícil de adquirir con otros instrumentos de evaluación más tradicionales que aportan una visión más fragmentada. El uso del portafolio también ha reflejado el trabajo sobre un conjunto de competencias transversales que difícilmente podíamos desarrollar a través de la clase expositiva tradicional y evaluar a través del examen final. Para determinar su efectividad en el proceso de enseñanza-aprendizaje-evaluación, se han realizado diferentes encuestas, además de analizar los resultados finales de la asignatura en relación al número de alumnos que la han superado. Los resultados muestran una mayor motivación del estudiante hacia la materia, una mayor implicación día a día, un descenso del número de abandonos, lo que en definitiva ha dado lugar a un mayor número de presentados y aprobados

Rampant Arch and Its Optimum Geometrical Generation

Gothic art was developed in western Europe from the second half of the 12th century to the end of the 15th century. The most characteristic Gothic building is the cathedral. Gothic architecture uses well-carved stone ashlars, and its essential elements include the arch. The thrust is transferred by means of external arches (flying buttresses) to external buttresses that end in pinnacles, which accentuates the verticality. The evolution of the flying buttresses should not only be considered as an aesthetic consideration, but also from a constructive point of view as an element of transmission of forces or loads. Thus, one evolves from a beam-type buttress to a simple arch, and finally to a rampant arch. In this work, we study the geometry of the rampant arch to determine which is the optimum from the constructive point of view. The optimum rampant arch obtained is the one with the common tangent to the two arches parallel to the slope line. A computer program was created to determine this optimal rampant arch by means of a numerical or graphical input. It was applied to several well-known and representative cases of Gothic art in France (church of Saint Urbain de Troyes) and Spain (Cathedral of Palma de Mallorca), establishing if they were designs of optimal rampant arches or not