Solid-State Transformers Can Boost Power Quality - Brief Article

USA Today (Society for the Advancement of Education), June, 2000

An engineering consortium led by Purdue University, West Lafayette, Ind., and the University of Missouri, Columbia, has taken a major step toward replacing the century-old technology behind the numerous, oil-filled power transformers that hang from utility poles in residential neighborhoods. It developed a new class of transformers that will smooth out the uneven voltages which plague today's grid and prematurely age electrical hardware ranging from lightbulbs to motors to power supplies in electronic equipment. They are designed with solid-state technology, meaning they rely primarily on semiconductor components such as transistors and integrated circuits instead of the heavy copper coils and iron cores of conventional transformers.

Transformers are essential elements of the power grid, converting the high-voltage electricity delivered by power lines to the 120-volt supply needed for consumers. Typically, one transformer supplies power to several homes. They come in three different types: pole-mounted canisters; ground-level metal boxes; and, though less rarely, underground transformers.

Although the solid-state transformers may not look very different on the outside, they promise major advantages, most importantly in what is referred to as power quality, which is profoundly influenced by users of the grid. 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 a user's appliances can reduce the voltage for neighboring users and cause power outages.

Solid-state transformers would eliminate all such power-quality problems as well as lowering the amount of current 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.

Another drawback of conventional transformers is that they continually waste electricity. "Even if you are away from home and nothing in your house is on, there are still losses in the transformer that go on all the time, and the utility pays for those losses," Sudhoff says, noting that the solid-state variety could reduce such waste. While costs for the materials used in conventional transformers are static, those associated with their solid-state counterparts are rapidly going down.