Design and Analysis of Low Frequency Transformer Applied in Fractional Frequency Transmission System

Power transformer is a key component in grid. A new type of transformer which operates on low frequency AC transmission (LFAC) is appealing because of its lower losses. This paper proposes a structure of low frequency transformer applied in fractional frequency transmission system (FFTS). The general geometry is built considering insulating properties firstly. Then, the transformer structure is optimized through generic algorism (GA) aiming at minimizing operating losses. It is proved that low frequency transformer has inherent advantages thanks to the weakened skin effect and eddy current especially when the transformer power is particularly large. Thus, finite element method (FEM) is used to show the performances compared with traditional power transformer.