Solid-state transformers ready to enable the Smart Grid?

Solid-state transformers ready to enable the Smart Grid?

The term solid-state transformer (SST) is something of a misnomer because it is not a transformer in the traditional sense. It is a collection of high-powered semiconductor components, conventional high-frequency transformers and control circuitry which is used to provide a high level of flexible control to power distribution networks. Add some communication capability and the entire package is often referred to as a smart transformer.

Recently, MIT's Technology Review magazine declared smart transformers to be one of the ten most important emerging technologies of the last twelve months. It specifically cited the work of Dr. Alex Huang, director of the FREEDM Systems Center at North Carolina State University for his work with high voltage semi-conductor materials such as silicon-carbon which have led to groundbreaking improvements in voltage handling capacity.

While the concept of SSTs has been around awhile, its use in high-powered utility level applications was deemed impractical due to the previous power limitations of existing semiconductor materials. However, with that hurdle seemingly overcome, the ability to directly integrate precise, high speed electronic control with high voltage power distribution may have arrived.

SST technology can step up or step down AC voltage levels just like that of the traditional transformer but it also offers several significant advantages. These include:

• allow two way power flow

• input or output AC or DC power

• actively change power characteristics such as voltage and frequency levels

• improve power quality (reactive power compensation and harmonic filtering)

• provide efficient routing of electricity based on communication between utility provider, end user site and other transformers in the network

• greatly reduce the physical size and weight of individual transformer packages with equivalent power ratings

When SSTs are implemented, they will radically change the way utility power is distributed. They will also become integral components in the future Smart Grid – enabling it to direct power from any source to any destination by the most efficient route possible.

To find out more information on SSTs and the Smart Grid visit the FREEDM Systems Center website at www.freedm.ncsu.edu/.

Michael J. Kawa