The Research Of A New Style Facts Technology-a Controllable Transformer

This paper proposes a new type of Flexible AC transmission system(FACTS) technology. An existing single-core three-phase transformerwith tap changers is converted into a controllable transformer byinterconnection between phases and adding small rated converters. Themagnitude and phase angle of the output voltage of a controllabletransformer are controlled simultaneously. Thus, real and reactive powerof controllable transformers can be controlled independently.The topology and principle of controllable transformer are analyzedin detail in this paper. Based on the detailed power electronic model ofcontrollable transformer, the output properties and dynamic ofcontrollable transformer is studied through simulation. Based on above,the principle of the power flow control using controllable transformer isanalyzed and verified by simulation results. Finally, preliminarydiscussion has been carried on using controllable transformer to dampinglow frequency oscillation.