American Superconductor Corp. (Westborough, Massachusetts, U.S.) and GE Industrial Systems (Plain-ville, Connecticut, U.S.) provided a D-VAR voltage-regulation systems to BC Hydro (Vancouver, British Columbia, Canada). The D-VAR, or Dynamic VAR, system will mitigate significant voltage problems in the town of Fort St. James, which is located in central British Columbia and resides near the end of a 70 km (43.5 mile), 66-kV radial transmission line.

During peak load, the line can experience voltage sags of up to 20%. Line events such as faults and the use of large motors in a nearby lumber mill further complicate these voltage problems. While the motors are starting, voltage may sag another 7% on the 66-kV transmission line. In addition, motor stalling also can potentially cause significant voltage sags.

Utilities and grid operators often face the challenge of finding ways to improve power reliability with their existing T&D infrastructure. In particular, long radial lines with widely varying loads often require support to maintain acceptable voltage levels. The D-VAR system, suited for this type of application, is expected to be operating by the end of November 2002, and will regulate voltage within BC Hydro's specifications, allowing for improved power reliability to customers in the area.

The D-VAR system maintains steady-state voltage levels on T&D lines and protects against other externally caused voltage disturbances, such as those caused by large motors in manufacturing facilities.

The D-VAR system is a mobile power reliability resource that uses the PowerModule power electronic converters to inject precise amounts of continuous and instantaneous reactive power (measured in VARs) into transmission grids to solve voltage-regulation and dynamic-voltage stability problems that otherwise may result in blackouts and brownouts.

Variations in the operating software and in the number of power electronic converters per unit allow users to customize D-VAR systems. The amount of reactive power delivered per unit varies from 3 to 8 MVARs continuous, with instantaneous reactive power output up to 18 MVAR per unit.
Circle 177 on Reader Service Card