New device protects distribution circuit from the effects of an erratic local load.

Two major North American utilities recently teamed with EPRI and Westinghouse to develop a distribution static compensator (DSTATCOM) that tames severe voltage flicker problems and saves up to $1.2 million over traditional solutions. When an International Forest Products (Interfor) sawmill in the rural Canadian community of Adam’s Lake announced plans to install a new whole-log chipper, driven by a single 1200-hp motor, a “red flag” went up at its energy provider, BC Hydro. In rural areas, it’s not uncommon for residential properties to mingle with industrial operations. From previous experience, BC Hydro knew the chipper would cause voltage flicker for the nearest 100 neighbors on the 25kV distribution feeder. A similar problem faced an American Electric Power (AEP) customer in Swayzee, Ind. Every time a nearby facility expanded, the increased load caused flicker problems. To maintain power quality on the 11-mile circuit, which serves about 1000 customers, only two of the three crushing plants could run at once.

Searching for a solution, both companies installed DSTATCOM. It reduced the flicker from 8% to an acceptable level of 4%. BC Hydro hopes to repeat its success with other customers. For more information, contact Ashok Sundaram at EPRI at (650) 855-2304, or e-mail