Eliminating fault-induced voltage sags at an industrial plant: a comparative evaluation of solutions

Sensitive electrical equipment in industrial facilities can be shut down suddenly by voltage sags. The tolerance of these devices to deviations in the magnitude of the supply voltage varies, but the most sensitive equipment often is critical to operations. This paper describes the results of a study that assessed methods for reducing the impact of voltage sags on an industrial plant power system. The study investigated several methods for reducing the depth of sags by modifying the electric utility and industrial power distribution systems. The study emphasized conventional methods of improving this aspect of power quality through system modifications, and especially on finding the most cost-effective methods. A sliding-fault method was used to determine the effectiveness of specific mitigation solutions.