Browsing by Author "Jahi, A."

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Citation - Scopus: 3
Analysis of Short Circuit Electromagnetic Force in a Three Winding Transformer Used in Solar System
(Institute of Electrical and Electronics Engineers Inc., 2021) Jahi, A.; Iskender, I.; 133746; Elektrik-Elektronik Mühendisliği
Due to the increasing of the fossil fuels prices in the past years and lack of these sources, all scientists encouraged to looking for the alternative energy sources. One of these energy sources is renewable solar energy. Power transmission from solar systems to grid is achieved using step up transformers. This type of transformer is energized from two inverter with or without variable frequency. Power transformers are deals with a variety of mechanical, electrical and thermal stresses during normal life time operation. Transient electromagnetic forces cause mechanical stress on transformer parameters where calculation of these forces with traditional methods is extremely complex due to the geometry of the transformer. Accordingly in this study, the electromagnetic forces takes place in the windings of a Photovoltaic (PV) transformer are investigated and for calculation of these forces, the 3D and 2D model of transformer is adapted in the ANSYS Workbench. The analysis of electromagnetic forces during the three line fault on high voltage side of the transformer are performed by the Finite Element Method (FEM) and compared with the analytical results. The numerical modeling technique discussed in this study would be useful in the design stage of PV transformer with regard to evaluate ability of transformer to withstand the short circuit current. © 2021 Chamber of Turkish Electrical Engineers.
Citation - Scopus: 8
Design and performance analysis of a three winding transformer used in solar system
(International Organization on 'Technical and Physical Problems of Engineering', 2021) Jahi, A.; Iskender, I.; 133746; Elektrik-Elektronik Mühendisliği
Due to the increasing of the fossil fuels prices in the past years and lack of these sources, all scientists encouraged to looking for the alternative energy sources. One of these energy sources is the renewable solar resources. Power transfer from solar systems to grid is achieved using step up transformers. This type of transformer is energized from a converter/inverter with or without variable frequency. The losses of such transformer are higher than those used in sinusoidal voltage power systems. This is due to harmonics content in the transformer input voltage and current. In this study the design and production of a PV transformer have been done according to the IEEE C57.159 guide and the loss analyses of transformer have been done using ANSYS MAXWELL considering the procedures proposed in standards of IEC 61378-1, IEEE C57.110 and the method proposed by Dowell. Finally, the thermal modeling and behavior of the transformer was investigated using the thermal model given in [25] to determine the hot spot and life time of the transformer using MATLAB program. © 2021, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.
Citation - Scopus: 2
Performance Analyses of a Three Winding Double Stack Pv Transformer
(International Organization on 'Technical and Physical Problems of Engineering', 2021) Jahi, A.; Iskender, I.; Elektrik-Elektronik Mühendisliği
Transformers are the main components of electrical systems and are widely used in renewable energy systems that transfer the energy they produce to the grid. Recently, due to the lack of fossil fuels, governments have encouraged utilities to seek alternative energy sources. In this respect, PV (Photovoltaic) power plants have become more important in recent years. Accordingly, transformers are one of the most critical equipment of PV plants, and their safe operation and stability in the electrical network are important. This type of transformer is energized from the inverter and needs to be customized to work with each system. The main purpose of this study is to analyze and model the magnetic field behavior of a special type PV transformer. This transformer has two similar separate windings on the low voltage side and one winding on the high voltage side. The simulation results are compared with those obtained from the experiments. The effects of the unbalanced operation of the inverters on the transformer performance were also investigated in this study. © 2021, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.