Search for dissertations about: "transformer-winding"
Found 5 swedish dissertations containing the word transformer-winding.
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1. A High Frequency Transformer Winding Model for FRA Applications
Abstract : Frequency response analysis (FRA) is a method which is used to detect mechanical faults in transformers. The FRA response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. READ MORE
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2. Multilevel three-phase dual active bridge dc-dc converters - A study on converter modulation, capacitive energy requirement, ZVS boundaries, MFT's winding connections, and core losses
Abstract : The collection and transmission of power from offshore wind turbines using dc have advantages over the ac system. One of the enabling technologies for deploying dc collection is the dc-dc converter that boosts the dc output from the turbine to the medium-voltage dc level of the collection grid. READ MORE
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3. Online power transformer diagnostics using multiple modes of microwave radiation
Abstract : In the present thesis, we propose and investigate a new approach to diagnose the effects of the various degradation mechanisms, including thermal degradation at hot spots, winding deformations due to the mechanical forces from short circuit currents, partial discharges due to local electric field surges, and increased moisture levels in the cellulose insulation due to decomposition, that affect electric power transformers during their normal operation in an electric power grid.Although the proposed diagnostics method can in principle be used to detect various degradation mechanisms mentioned above, we focus in the present thesis on mechanical deformations of transformer winding structures. READ MORE
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4. Differential Protection for Arbitrary Three-Phase Power Transformers
Abstract : This thesis describes how to provide standardized, current based, differential protection for any three-phase power transformer, including phase-shifting transformers with variable phase angle shift and transformers of all construction types and internal on-load tap-changer configurations. The use of standard transformer differential protection for such applications is considered impossible in the protective relaying standards and practices currently applied. READ MORE
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5. Diagnostics of Oil-Impregnated Paper Insulation Systems by Utilizing Lightning and Switching Transients
Abstract : Development of the power gridtowards a more reliable and smarter system requires frequent on-line monitoring of the power components. Power transformers and their bushings are particularly important components in a power transmission system and their insulation degradation may lead to catastrophic failures. READ MORE