Changing of the guard: Transformers go electronic

West Lafayette, Ind.-A new type of transformer that relies on semiconductor components could someday replace the century-old, oil-filled power transformers that hang from utility poles if engineers from Purdue University and the University of Missouri have their way.

The consortium of engineers developed a new class of transformers that will smooth out the uneven voltages that plague today's grid. The new type of transformers are designed with solid-state technology, meaning they rely on semiconductor components such as transistors and integrated circuits instead of the heavy copper coils and iron cores of conventional transformers.

Asea Brown Boveri Ltd., an engineering and technology company with headquarters in Zurich, Switzerland, sponsors the work. The company just received a patent for the solid-state transformer, which should replace existing technology over the next decade, said Scott Sudhoff, an associate professor at the Purdue School of Electrical and Computer Engineering.

Transformers are essential elements of the power grid; they convert the high-voltage electricity that power lines deliver to the 120-volt supply consumers need.

Typically, one transformer supplies power to several homes. They come in three varieties: the pole-mounted canisters; ground-level metal boxes commonly painted green or blue; and, rarely, underground transformers.

The solid-state transformers don't look very different on the outside, but they promise major advantages on the inside-most importantly in an area referred to as power quality. For example, some power equipment in homes, businesses, and industry introduces electrical "pollution" that is passed on to neighbors, causing motors in various appliances to run less efficiently, heat up, and go slower. The pollution causes voltages to fluctuate, affecting electrical devices such as lightbulbs, which flicker and burn out faster. Heavy loads in one user's appliances can reduce the voltage for neighboring users and cause power outages.

Solid-state transformers could eliminate those power quality problems. They could also reduce the amount of current actually required to supply devices such as electric machinery, cutting down on losses associated with the transmission of electricity throughout the power grid. In addition, solid-state transformers represent an environmental improvement because they do not contain mineral oil, an insulation that can leak and pollute the environment.

The Energy Systems Analysis Consortium, which is made up of Purdue, the University of Missouri-Rolla, the University of WisconsinMilwaukee, the U.S. Navy Postgraduate School, and the U.S. Naval Academy, is developing the transformers. Asea Brown Boveri owns all rights to the transformer patent.