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The growth in the demand for electricity has led to the development and application of technologies that make its means of transport more efficient. Thus, one of these options is the implementation of transmission lines in HVDC. One of important design parameters of these lines is to know their magnetic field distribution, when it is required to calculate it, there is no methodology that can be applied to HVDC transmission lines. The following article presents a methodology that allows obtaining the density of the magnetic field on the corridor of an overhead transmission line. A case study of a 500 kV bipolar line in HVDC is presented, the results obtained are compared using the commercial software Field and corona Effects (FACE), the results obtained are consistent with those obtained from the presented methodology. An analysis of the impact of the transmission line configuration on the magnetic field density is developed, defining the most efficient configuration.

The effect of the galvanic corrosion process taking place between aluminium alloy (AA2024-T3) and carbon fiber reinforced plastic (CFRP) immersed in 0.05 M NaCl was studied using organic and inorganic compounds as corrosion inhibitors. Electrochemical approaches such as electrochemical noise analysis (ENA) and electrochemical impedance spectroscopy (EIS) were carried out to evaluate efficiencies of 1,2,4-triazole (C2H3N3) and cerium nitrate hexahydrate (Ce(NO3)3·6H2O) as corrosion inhibitors. The highest efficiency was reached for Ce(NO3)3.6H2O, with some improvement observed by adding C2H3N3 in a mixed inhibitor solution. The noise resistance (Rn) and polarization resistance (Rp) values calculated from ENA and EIS data showed almost identical behavior with different magni­tudes but similar trends. Adsorption isotherm models estimated with fractional surface coverage (q) parameter were fitted better to Langmuir model for C2H3N3 and Temkin model for Ce(NO3)3·6H2O. The calculated values of Gibbs free energy suggested physi­sorption and chemisorption as spontaneous interactions between a metal surface and both inhibitors. Energy-dispersive X-ray spectroscopy (EDS) was carried out before and after immersing AA2024-T3 in the electrolyte, identifying rich zones in copper with cerium deposited over it and confirming the presence of rare-earth oxide deposition and oxide film products. The EDS analysis for CFRP revealed the deposition of Ce and Al particles over its surface after immersion in the electrolyte, especially in the areas rich in carbon.

Ballistic electron transport in a silicene structure, composed of a pair of magnetic gates, in the ferromagnetic and an-tiferromagnetic configuration is studied. This theoretical study has been done using the matrix transfer method to calculate the transmission, the conductance for parallel and antiparallel magnetic alignment and the magnetoresistance. Results show that conductance and magnetoresistance oscillate as a function of the length between the two magnetic domains. The forbidden transmission region also increases as a function of the barrier separation distance.

En este artículo se analiza una red de distribución urbana de 23 kV típica de la zona central de México. El objetivo es determinar la distancia máxima de separación entre apartarrayos de línea que permita reducir las salidas de los circuitos de distribución por descargas atmosféricas directas e indirectas. Con base en las características eléctricas, ambientales, ceráunicas y geográficas de la zona, niveles de cortocircuito y las sobretensiones provocadas por maniobras rutinarias, se selecciona el apartarrayos siempre con el principal objetivo de determinar su espaciamiento adecuado sobre la línea para que éste funcione apropiadamente. La investigación se lleva a cabo con la ayuda del software llamado Alternative Transients Program (ATP) donde se realiza el cálculo de los parámetros de la línea utilizando el modelo de K.C. Lee, las sobretensiones transitorias por onda viajera y por conexión de capacitores también son simuladas. La motivación de este trabajo consiste principalmente en contar con un mayor sustento teórico y técnico (actualmente escueto) para determinar el espaciamiento entre apartarrayos de la red de distribución considerada y así aumentar la calidad del suministro eléctrico de la zona.

It is very important for the car users to have several communication systems and many antennas, which respond to the demands of aesthetics and efficiency. In this case, it is necessary to consider different types of materials and geometries. Among the automobile systems, the navigation systems are found, which are formed by a Global Position System (GPS), with a pre-charged base of maps and highways in order to locate the vehicle. For the reception of the GPS signals, circularly polarized patch antennas are used, which must be designed to operate at 1.57 GHz. This work is focused on the analysis of a circular antenna performance, designed for GPS, by means of the simulation of the following cases: antenna without radome, antenna with acrylic radome, and, finally, antenna on the roof of an automobile, considering the effect of the complete chassis. A Basic, a Simplified and a More Simplified Advanced Car Models (BCM, SACM, and MSACM) were used in order to analyze the chassis shape. The simulations were carried out with the software FEKO. The fabrication and experimental and practical tests are also presented.

Esta investigación presenta la simulación de las sobretensiones ocurridas durante una maniobra de mantenimiento en un compensador estático de potencia reactiva de 230 kV. El incorrecto funcionamiento de un interruptor de potencia causa una falla catastrófica que incluye la explosión y el incendio del equipo. La Información obtenida de investigaciones previas, donde se analizan los estados estable y transitorio del compensador, no toma en cuenta la combinación del comportamiento del compensador y la fallida operación de los medios de desconexión. La incorrecta apertura de uno de los polos del interruptor de potencia del compensador provoca sobretensiones interesantes las cuales están relacionadas con las componentes armónicas de tensión y corriente generadas por un elemento clave de la falla: el reactor controlado por tiristores. En este trabajo se utiliza el Software Alternative Transients Program (ATP) para modelar el compensador y obtener el cálculo de las sobretensiones transitorias. Se analizan las frecuencias naturales y el espectro armónico de las señales manejadas por el compensador. Con la ayuda de una videograbación se muestran imágenes reales de los arcos eléctricos generados debido a las sobretensiones. Este estudio se realiza por primera vez en este compensador estático y la información resultante es de mucha utilidad futura para el diseño eléctrico y la planificación de la operación de las redes de potencia.