Opis: In this master’s thesis, we have established a model of a transformer winding. This model is based on the multi transmission line theory that allows us to model each turn of the winding separately. By using that approach, it was possible to calculate the frequency response of a winding in the required frequency range from 20 Hz to 2 MHz. The purpose of this simulation was to evaluate the frequency response analysis as a diagnostic tool for deformations of windings in power transformers. An evaluation was performed using sensitivity analysis of several parameters that indicate winding deformations. Finally, axial bending deformation was simulated and successfully diagnosed by applying the frequency response analysis. Ključne besede:Power transformer, Frequency response analysis, Diagnostics, MTL model Objavljeno v DKUM: 03.11.2020; Ogledov: 756; Prenosov: 64 Celotno besedilo (2,64 MB)

Opis: An approach to improvement of interconnections of a summarised geometric dimension and the power parameters of electric machines, transformers and electric devices is determined based on a generalisation of theoretical and experimental research results. Ključne besede:electric machine, transformer, electric device, generalised linear dimension Objavljeno v DKUM: 10.07.2015; Ogledov: 1126; Prenosov: 27 Povezava na celotno besedilo

Opis: In this paper, parameters of the Jiles-Atherton (J-A) hysteresis model are identified using a stochastic search algorithm called differential evolution (DE). The J-A hysteresis model's parameters are identified by DE in such a way, that best possible agreement is obtained between the measured and model calculated hysteresis loops. This agreement is furthermore increased by improving the J-A hysteresis model. The improvement is achieved by replacing a constant pinning parameter in the J-A hysteresis model with a variable one. Here, the variable pinning parameter is written as a function of a magnetic field. Bz DE identified parameters are used in the J-A hysteresis model, which is included in the dynamic model of a single-phase transformer. The effectiveness of the improved J-A hysteresis model and parameters identification approach is verified with experiments and simulations. Ključne besede:Jiles-Atherton model, J-A hysteresis model, magnetic hysteresis, optimization methods, parameters estimation, single-phase transformer Objavljeno v DKUM: 31.05.2012; Ogledov: 2046; Prenosov: 82 Povezava na celotno besedilo