Design and implementation of 34,5 kV zig-zag grounding transformatör

In this thesis, modeling of a 34.5 kV zigzag grounding transformer to be used to create a neutral point in ungrounded systems was explained. Finite element models (FEM) of the zigzag transformer with a core with nonlinear magnetic characteristics were created using Ansys Maxwell software. Core loss and leakage reactance, which are important criteria for grounding transformer design, are discussed. Using the finite element method of the Ansys program, the magnetic flux density and iron losses of the 2D and 3D models of the zigzag transformer were examined and compared. A numerical method based on finite element analysis (FEA) for single-phase three-dimensional and three-phase three-dimensional is presented for leakage reactance. Magnetic vector potential formulation was used to solve these models. The prototype grounding transformer was produced with the help of the finite element method. The accuracy of these methods was compared with experimental results. Experimental results show that the three-phase 3D model of the zigzag transformer obtains more accurate leakage reactance value than the single-phase 3D model, and the 3D model provides better accuracy in iron losses than the 2D model. KEYWORDS: Grounding