DIE - DIAMAT - Comunicaciones en congresos y otros eventos
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Publication Application of biodegradable fluids as liquid insulation for distribution and power transformers(IEEE, 2020-06-09) García de Burgos, María Belén; Ortiz, Alfredo; Renedo, Carlos; Burgos Díaz, Juan Carlos; García Gómez, Diego Fernando; Pérez Rosa, Daniel; European Commission; Ministerio de Ciencia, Innovación y Universidades (España)In the last years the use of biodegradable fluids as liquid insulation for distribution and power transformers is becoming more common. The main biodegradable fluids are the natural and synthetic esters, although biodegradable hydrocarbons have been recently proposed as well. Biodegradable fluids have a much lower environmental impact than mineral oil, limiting the risk of soil contamination in case of leaks what makes them a suitable solution for some applications, as off-shore transformers or railway transformers. Additionally, these fluids have higher flash point than conventional mineral oils what reduces dramatically the risk of fire and collateral damage derived from explosion and fire. Despite of these advantageous factors, there are still some aspects that hinders the spread of their use, such as the difference on thermal properties, the lack of accepted maintenance procedures and the price. This paper presents the current situation of biodegradable insulating fluids, analyzing some of their properties and discussing the aspects that are still to be investigated to make them a real alternative to petroleum-based fluids.Publication Designing a Rogowski Coil with Particle Swarm Optimization(Mdpi Ag, 2018-11-15) Robles Muñoz, Guillermo; Shafiq, Muhammad; Martínez Tarifa, Juan ManuelPublication Planar Localization of Radio-Frequency or Acoustic Sources with Two Receivers(MDPI, 2017-11-14) Fresno de Marcos, José Manuel; Robles Muñoz, Guillermo; Martínez Tarifa, Juan ManuelSpatial localization of emitting sources is especially interesting in different fields of application. The focus of an earthquake, the determination of cracks in solid structures or the position of bones inside a body are some examples of the use of multilateration techniques applied to acoustic and vibratory signals. Radar, GPS and wireless sensors networks location are based on radiofrequency emissions and the techniques are the same as in the case of acoustic emissions. This paper is focused on the determination of the position of sources of partial discharges inside electrical insulation for maintenance based on the condition of the electrical machine. The use of this phenomenon is a mere example of the capabilities of the proposed method because its emission can be electromagnetic in the UHF range or acoustic when the insulation is immersed in oil. Generally, when a pulse is radiated from a source, the wave will arrive to two receivers at different times. One of the advantages of measuring these time differences of arrival or TDOA is that it is not required a common clock as in other localization techniques based on the time of arrival (TOA) of the pulse to the receiver. With only two sensors, all the possible points in the plane that would give the same TDOA describe a hyperbola. Using an independent third receiver and calculating the intersection of the three hyperbolas will give the position of the source. Therefore, planar localization of emitters using multilateration techniques can be solved at least with three receivers. This paper presents a method to locate sources in a plane with only two receivers, one of them in a fixed position and the other is placed describing a circumference around the first one. The TDOA are measured at different angles completing a total turn and obtaining a function, angle versus TDOA, that has all the geometric information needed to locate the source.Publication Power Quality in distribution power networks with photovoltaic energy sources(2009) Albarracín Sánchez, Ricardo; Amarís Duarte, Hortensia ElenaSolar radiation is characterized by short fluctuations introduced by passing clouds. These solar fluctuations will produce Voltage and power fluctuations at the PCC (Point of common coupling). Flicker level should be evaluated by using a flickermeter according to the standard IEC 61000-4-15. Models of the solar fluctuation, photovoltaic modules and power converter are shown in this paper and the flickermeter model is tested according to the IEC requirements and the CIGRE/CIRED/UIE test protocol.Publication A Partial Discharges Acquisition and Statistical Analysis Software(IEEE, 2012-05-13) Ardila Rey, Jorge Alfredo; Martínez Tarifa, Juan Manuel; Robles Muñoz, Guillermo; Rojas Moreno, Mónica Victoria; Albarracín Sánchez, RicardoPartial Discharges (PDs) are responsible forunexpected failures in power system equipment, so theirmeasurement is a fundamental tool for electrical equipmentmaintenance. In order to characterize PDs activity, somestatistical magnitudes are necessary. For this purpose, PDsacquisition and processing is an important tool for criticaldecisions related to power systems. In this paper, the maindifficulties and challenges facing PDs detection, acquisition andprocessing are presented. Results will be compared to acommercial PDs detection system.Publication Antenna selection and frequency response study forUHF detection of partial discharges(IEEE, 2012-05-13) Robles Muñoz, Guillermo; Martínez Tarifa, Juan Manuel; Rojas Moreno, Mónica Victoria; Albarracín Sánchez, Ricardo; Ardila Rey, Jorge AlfredoPartial Discharge (PD) detection is a widely extended technique for electrical insulation diagnosis. Classical PD detection by means of phase resolved patterns require electrical connections to the power equipment and is sensitive to many noise sources. Ultra High Frequency (UHF) detection techniques are being recently proposed to overcome these problems, and to detect partial discharges on-line. In this paper, four antennas will be tested in order to compare their response to this physical phenomenon.