Influence of instrument transformers on power system protection

Instrument transformers are a crucial component of power system protection. They supply the protection system with scaled-down replicas of current and voltage signals present in a power network to the levels which are safe and practical to op- erate with. The conventional instrument transformers are based on electromagnetic coupling between the power network on the primary side and protective devices on the secondary. Due to such a design, instrument transformers insert distortions in the mentioned signal replicas. Protective devices may be sensitive to these distortions. The inuence of distortions may lead to disastrous misoperations of protective devices. To overcome this problem, a new instrument transformer design has been devised: optical sensing of currents and voltages. In the theory, novel instrument transform- ers promise a distortion-free replication of the primary signals. Since the mentioned novel design has not been widely used in practice so far, its superior performance needs to be evaluated. This poses a question: how can the new technology (design) be evaluated, and compared to the existing instrument transformer technology? The importance of this question lies in its consequence: is there a necessity to upgrade the protection system, i.e. to replace the conventional instrument transformers with the novel ones, which would be quite expensive and time-consuming? The posed question can be answered by comparing inuences of both the novel and the conventional instrument transformers on the protection system. At present, there is no systematic approach to this evaluation. Since the evaluation could lead to an improvement of the overall protection system, this thesis proposes a comprehensive and systematic methodology for the evaluation. The thesis also proposes a complete solution for the evaluation, in the form of a simulation environment. Finally, the thesis presents results of evaluation, along with their interpretation

Binap and Phosphoramidites as Privileged Chiral Ligands for the Metal-Catalyzed Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Ylides

2,2′-Bis(diphenylphosphino)-1,1′-binaphthyl (binap) and phosphoramidites are privileged chiral ligands that have been tested in the coinage-metal-catalyzed 1,3-dipolar cycloadditions of metalloazomethine ylides and electrophilic alkenes. Silver(I), copper(II), and gold(I) salts have been evaluated in all of these reactions. Maleimides, acrylates, fumarates, 1,2-bis(phenylsulfonyl)ethylene, and enones reacted with imino esters to give the corresponding endo-prolinates, such as hepatitis C (HCV) inhibitors, in high diastereo- and enantioselectivity using either binap–silver and –gold(I) or phosphoramidite–silver complexes. In the case of nitroalkenes, exo-4-nitroprolinates were obtained using silver or copper(II) phosphoramidite complexes. Azlactones reacted with maleimides and acrylates to give pyrrolines only in the presence of binap–gold(I) complexes. The observed enantioselectivity and mechanism of these 1,3-dipolar cycloadditions were studied for the most relevant examples by means of DFT calculations.Our work has been supported by the Spanish Ministerio de Ciencia e Innovación (MICINN) (CTQ2004-00808/BQU, Consolider INGENIO 2010 CSD2007-00006, CTQ2007-62771/BQU, CTQ2010-20387 and the Hispano-Brazilian project PHB2008-0037-PC), the Spanish Ministerio de Economia y Competitividad (MINECO) (projects CTQ2013-43446-P and CTQ2014-51912-REDC) FEDER, Generalitat Valenciana (PROMETEO/2009/039, and PROMETEOII/2014/017), and by the University of Alicante

Multicomponent synthesis of unnatural pyrrolizidines using 1,3-dipolar cycloaddition of proline esters

The synthesis of unnatural pyrrolizidines has been studied using a multicomponent-domino process involving proline or 4-hydroxyproline esters, an aldehyde and a dipolarophile. The formation of the iminium salt promotes the 1,3-dipolar cycloaddition affording highly substituted pyrrolizidines under mild conditions and high regio- and diastereoselectivities.This work has been supported by the DGES of the Spanish Ministerio de Ciencia e Innovación (MICINN) (Consolider INGENIO 2010 CSD2007-00006, CTQ2007-62771/BQU, CTQ2010-20387), FEDER Generalitat Valenciana (PROMETEO/2009/039), and by the University of Alicante