Browsing by Keyword "Protection"
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Item Definition of the procedure to determine the suitability and durability of an anti-graffiti product for application on cultural heritage porous materials(2012-01) García, Oihana; Malaga, Katarina; Tecnalia Research & InnovationAnti-graffiti protection is becoming a common practice in many urban buildings, especially in areas of social decay. When Cultural Heritage objects are affected by graffiti, the application of anti-graffiti products can result not only in an unsatisfactory result but also in an irreversible damage of an invaluable cost. The materials commonly found in these constructions are very frequently porous and present different types of decay forms. For this reason, the protection of these materials should be carefully considered. This paper proposes a criterion to decide on the suitability and durability of an anti-graffiti product prior to its application in a porous surface of a protected building. Performance classifications are defined for a series of properties including colour and gloss, and hydric and durability properties, and minimum acceptable values or reductions in these properties are recommended.Item Gazela: asesor digital de redes sociales para adolescentes(2012-09-01) Isasi-Andrieu, Alberto; López-Carrera, Ångel; Ruiz-Ibáñez, Pilar; Angulo-Redondo, Iñaki; Tecnalia Research & Innovation; CIBERSEC&DLT; SG; SG; DIGITAL ENERGYSocial networks are becoming overcrowded. Every day people share millions of files, videos and pictures, and the massive use of social networks is replacing other communications channels such as telephone, e-mail or sms. However, these networks are often used without knowing the possible repercussions. Gazela is a platform with the aim to provide the general society and especially teenagers with the necessary tools to allow them to guarantee their privacy while using social networks. Gazela's activity is focused on three main elements: surveillance services, protection services and legal advising services.Item Matrix converter: Improvement on the start-up and the switching behavior(2008) Andreu, Jon; De Diego, José Miguel; De Alegría, Iñigo Martínez; Kortabarria, Iñigo; Martín, José Luis; Ceballos, Salvador; POWER ELECTRONICS AND SYSTEM EQUIPMENTThe matrix converter (MC) presents a promising topology that needs to overcome certain barriers (protection systems, durability, the development of converters for real applications, etc.) in order to gain a foothold in the market. Taking into consideration that the great majority of efforts are being oriented towards control algorithms and modulation, this article focuses on MC hardware. In order to improve the switching speed of the MC and thus obtain signals with less harmonic distortion, several different IGBT excitation circuits are being studied. Below, the appropriate topology is selected for the MC and a configuration is presented which reduces the excursion range of the drivers and optimizes the switching speed of the IGBTs. Inadequate driver control can lead to the destruction of the MC due to its low ride-through capability. Moreover, this converter is specially sensitive during start-up, as at that moment there are high overcurrents and overvoltages. With the aim of finding a solution for starting-up the MC, a circuit is presented (separate from the control software) which ensures a correct sequencing of supplies, thus avoiding a short-circuit between input phases. Moreover, it detects overcurrent, connection/disconnection, and converter supply faults. Faults cause the circuit to protect the MC by switching off all the IGBT drivers without latency. All this operability is guaranteed even when the supply falls below the threshold specified by the manufacturers for the correct operation of the circuits. All these features are demonstrated with experimental results. For all these reasons, it can be said that the techniques proposed in this article substantially improve the MC start-up cycle, representing a step forward towards the development of reliable matrix converters for real applications.Item New fault tolerant matrix converter(2011-02) Ibarra, Edorta; Andreu, Jon; Kortabarria, Iñigo; Ormaetxea, Enekoitz; De Alegría, Iñigo Martínez; Martín, José Luís; Ibañez, Pedro; SGThe matrix converter (MC) presents a promising topology that will have to overcome certain barriers (protection systems, durability, the development of converters for real applications, etc.) in order to gain a foothold in the industry. In some applications, where continuous operation must be insured in the case of a system failure, improved reliability of the converter is of particular importance. In this sense, this article focuses on the study of a fault tolerant MC. The fault tolerance of a converter is characterized by its total or partial response in the case of a breakage of any of its components. Taking into consideration that virtually no work has been done on fault tolerant MCs, this paper describes the most important studies in this area. Moreover, a new method is proposed for detecting the breakage of MC semiconductors. Likewise, a new variation of SVM modulation with failure tolerance capacity is presented. This guarantees the continuous operation of the converter and the pseudo-optimum control of a PMSM. This paper also proposes a novel MC topology, which allows the flexible reconfiguration of this converter, when one or several of its semiconductors are damaged. In this way, the MC can continue operating at 100% of its performance without having to double its resources. In this way, it can be said that the solution described in this article represents a step forward towards the development of reliable matrix converters for real applications.Item New protection circuit for high-speed switching and start-up of a practical matrix converter(2008) Andreu, Jon; De Diego, José Miguel; de Alegria, Iñigo Martinez; Kortabarria, Iñego; Martin, José Luis; Ceballos, Salvador; POWER ELECTRONICS AND SYSTEM EQUIPMENTThe matrix converter (MC) presents a promising topology that needs to overcome certain barriers (protection systems, durability, the development of converters for real applications, etc.) in order to gain a foothold in the market. Taking into consideration that the great majority of efforts are being oriented toward control algorithms and modulation, this paper focuses on MC hardware. In order to improve the switching speed of the MC and thus obtain signals with less harmonic distortion, several different insulated-gate bipolar transistor (IGBT) excitation circuits are being studied. Here, the appropriate topology is selected for the MC, and a recommended configuration is selected, which reduces the excursion range of the drivers, optimizes the switching speed of the IGBTs, and presents high immunity to common-mode voltages in the drivers. Inadequate driver control can lead to the destruction of the MC due to its low ride-through capability. Moreover, this converter is especially sensitive during start-up, as, at that moment, there are high overcurrents and overvoltages. With the aim of finding a solution for starting up the MC, a circuit is presented (separate from the control software), which ensures correct sequencing of supplies, thus avoiding a short circuit between input phases. Moreover, it detects overcurrent, connection/disconnection, and converter supply faults. Faults cause the circuit to protect the MC by switching off all the IGBT drivers without latency. All this operability is guaranteed even when the supply falls below the threshold specified by the manufacturers for the correct operation of the circuits. All these features are demonstrated with experimental results. Lastly, an analysis is made of the interaction that takes place during the start-up of the MC between the input filter, clamp circuit, and the converter. A variation of the clamp circuit and start-up strategy is presented, which minimizes the overcurrents that circulate through the converter. For all these reasons, it can be said that the techniques described in this paper substantially improve the MC start-up cycle, representing a step forward toward the development of reliable MCs for real applications.Item Sequencing of supplies of the matrix converter: Improvement of the start-up and MC interaction with the filter and clamp circuit(2008) Andreu, J.; De Diego, J. M.; De Alegria, I. M.; Kortabarria, I.; Martín, J. L.; Ceballos, S.; POWER ELECTRONICS AND SYSTEM EQUIPMENTThe matrix converter (MC) presents a promising topology that needs to overcome certain barriers (protection systems, durability, the development of converters for real applications, etc.) in order to gain a foothold in the market. This article focuses on MC hardware. In order to improve the switching speed of the MC and thus obtain signals with less harmonic distortion, the appropriate driver topology is selected. Inadequate driver control can lead to the destruction of the MC. Moreover, this converter is specially sensitive during start-up, as at that moment there are high overcurrents and overvoltages. With the aim of finding a solution for starting-up the MC, a circuit is presented which ensures a correct sequencing of supplies, thus avoiding a short-circuit between input phases. Furthermore, it detects overcurrent, connection/disconnection, and converter supply faults. Faults cause the circuit to protect the MC by switching off all the IGBT drivers without latency. Lastly, an analysis is made of the interaction that takes place during the start-up of the MC between the input filter, clamp circuit and the converter. A variation of the clamp circuit strategy is presented which minimizes the overcurrents that circulate through the converter. For all these reasons, it can be said that the techniques described in this article substantially improve the MC start-up cycle, representing a step forward towards the development of reliable matrix converters for real applications.Item Superconducting circuit breaker concepts for the protection of HVDC systems(Institution of Engineering and Technology, 2019) Larruskain, D. M.; Etxegarai, A.; Iturregi, A.; Abarrategi, O.; Apiñaniz, S.; POWER ELECTRONICS AND SYSTEM EQUIPMENTThe reliable protection of DC grids is still a challenge, mainly because of the fast operation required for interrupting the high current faults that could severely damage the system. Accordingly, HVDC circuit breakers must be further developed. On the other hand, superconducting fault current limiters reduce fault currents and are able to adapt the performance of the system to the maximum breaking capacity of circuit breakers. In the present paper, a superconducting DC circuit breaker is proposed considering three circuit breaker technologies. Those technologies are compared and their performance is analysed on a multiterminal HVDC system. The paper highlights the benefits that the superconducting fault current limiter provides to the circuit breaker operation.