Modeling and analysis of a non-linear loaded single-phase transformerconsidering the saturation effect

The ever-increasing world population and developing industry increase energy demand or consumption tremendously. The importance of producing and transmitting clean energy that does not harm nature is increasing day by day. Most of the energy consumed today is produced in power plants. This generated energy is generally transmitted as alternating current. Power transformers are used to change the voltage level along the transmission line. Therefore, the design, production, protection, maintenance and modeling of power transformers is important and is an area that needs constant research and development. Nonlinearity of transformers; It is caused by saturation, hysteresis and eddy currents in the core. These effects distort the excitation current waveform at no load and play an important role on the transient behavior of the transformer. Therefore, taking into account the hysteresis loop in modeling the transformer is very necessary to understand the effects of core nonlinearity In modern electrical distribution systems, the use of nonlinear loads such as power supplies, rectifier circuits, electrical appliances, adjustable speed drives is on the rise. While these nonlinear loads draw non-sinusoidal currents from the network, they also cause distortions in the voltage and current waveforms called harmonics. The presence of harmonics in power lines causes low power factor, low efficiency, increased power losses in the distribution system and interference problems. The increase in nonlinear load also causes the total harmonic distortion to increase and therefore increases the loading on the transformer. In this study, a transformer model that includes the hysteresis and saturation effects of the transformer was created. Matlab/Simulink simulation was carried out using the inverse Jiles-Atherton hysteresis model to take into account the hysteresis loop in the modeling process of the transformer and to analyze it, including the saturation effect, harmonic effects and the effects of inrush currents. The transformer model, which was created according to different energization angles of the primary voltage, was operated without load and the change of energization current and saturation effects were examined. The effects of non-linear load conditions on the transformer were analyzed for different trigger angles by adding a single-phase controlled rectifier to the created model. Harmonic analysis and total harmonic distortion changes of the input and output quantities of the transformer for different load situations are given in detail.