Conceptual study and operational overview on Variable Frequency Transformer used for grid interconnections

Abstract

Electric-power transmission is the bulk transfer of electrical enen�y, from �eneratin� power plants to electrical substations located near demand centers. Electricity is transmitted at hi�h volta�es (110 kV or above) to reduce the energy lost in long-distance transmission. Since 2004, an alternative technology has been in commercial operation in North America, which has proven to be a reliable and stable vehicle to move power between two points. The two points in question need not be synchronous. This technolo�y is the Variable Frequency Transformer, or VFT. Variable frequency transformers provide transmission solutions for a smarter �rid, enablin� transmission system operators to control power flows between power �rids with high reliability, speed and efficiency, while offering flexibility It is a controllable, bi-directional transmission device that can transfer power between asynchronous networks. Variable Frequency Transformers can convert this power to and from grids without converting the power into DC thus eliminating the harmonic distortions. Another advantage with VFT is that we can have infinite phase shifts between the two powers where as in conventional devices we could have only few predefined phase shifts. This paper introduces the VFT and provides a brief explanation of the technology and its benefits.

Research on Variable Frequency Transformer: A Smart Power Transmission Technology

“…Alternatively, asynchronous interconnection can also be made by the variable frequency transformer (VFT). Over the past decade, the VFT has proven itself to be an effective means for asynchronous interconnection, and a perfect contender of PST in synchronous interconnection [63], [64]. The VFT was initially introduced by General Electric (GE) in the US in the 1990s and successfully used on the power grid in the early 21st century.…”