As we push the physical limits of the grid, flexible ac transmission systems controllers can prevent systems from coming apart. Interestingly, FACTS technology has been with us for about four decades, but it is attracting more interest today as we restructure the grid.
FACTS devices have matured and increased beyond all of the expectations of those involved with the technology in those early days, so much so that today's manufacturers are hard-pressed to meet the demand for services. With the present emphasis on marketing and high financial returns, there is a greater need today than ever before for new types of FACTS controllers that support those pressures.
A few years ago, the voltage source converter technology was applied to FACTS devices. These controllers use transistors instead of thyristors. This has led to self-commutative controllers that have smaller footprints improved characteristics and faster reponse times. Controllers are also turning up on distribution circuits, solving problems caused by large penetrations of rooftop solar and community wind generators.
Energy storage has been combined with FACTS devices to address other problems, both on the distribution feeder and in renewable energy installations, which is timely since renewable energy is one of the fastest growing portions of our industry. These green electrons bring some of the most challenging transmission and distribution issues, too, such as voltage swings and bidirectional power flows.
More than 30 years have passed since that fateful dynamic stabilizer project. FACTS controllers have become more complex and sophisticated, controlling about every parameter and variable of the transmission line and distribution feeder. And it is just as exciting today as it was when I first met the technology.
Following are images from Transmission & Distribution World's July supplement feature, Grid FACTS, on how this type of power electronics is poised to refine and alter the 21st century grid.