A transformer is a device that changes the voltage level of an AC electric power through a magnetic field. Since DC power systems have significant drawbacks at power transmission, almost all electric power generation and power transmission systems around the world are AC power systems. Since most of the AC power systems are in the form of three-phase AC circuits. Three-phase AC power systems have more advantages compared to one-phase systems because the three-phase systems allow more power delivered through the same amount of metal. In a three-phase system, all components should consist of three-phase including generators, transformers, and loads. So, three-phase transformers are quite essential in real-world applications.