The role of custom power products in enhancing power quality at industrial facilities

New technologies, using power electronics-based concepts, have been developed to provide protection for commercial and industrial customers from power quality problems on the electrical distribution system. Known as custom power products, the technologies described in this paper provide protection against sags, swells, voltage flicker, harmonics, and other power quality concerns. The custom power products can increase the availability of sensitive load and reduce costs associated with process interruptions. This paper covers two custom power products that were developed by Westinghouse Electric Corporation under contract to the Electric Power Research Institute (EPRI). The dynamic voltage restorer (DVR), which is a series-connected power electronics based device, quickly compensates for power system sags and swells. The distribution static compensator (DSTATCOM), which is a shunt-connected power electronics-based device, protects the electrical system from a polluting (flicker-producing) load. The DSTATCOM can be used in place of a traditional static VAr compensator and offers many advantages.