Two-Winding Transformer in Symmetrical Components

The paper deals with the issue of symmetrical components in transformers, considering various winding connections in the occurrence of different types of faults. The transformer is a determining element for the connection of the equivalent model in the zero-sequence and, therefore, also determines the magnitude of the impedance in the zero-sequence and the magnitude of the zero-sequence current. The equivalent model in the zero sequence primarily affects fault currents and voltage in the electrical grid during the most common fault, the phase-to-ground fault. The theory of component systems is well-known and widely published. This paper aims to explain the properties of a two-winding transformer in symmetrical component systems based on the results of simulations implemented in MATLAB.