Modelling and basic properties of three-phase hybrid transformer with unsynchronized active load

This paper deals with three-phase power system with hybrid transformer (HT). The HT contains conventional transformer with electromagnetic coupling and PWM AC line chopper integrated with secondary windings with electric coupling. The HT is located between distribution system and Local Balancing Area (LBA) with small power local energy sources. After description of the three-phase power system with hybrid transformer (HT) and unsynchronized active load, the mathematical and circuit models of the AC source with HT is presented. These models are verified by means of the simulation and experimental test results obtained for HT of about 3 kV A.