Novel cost-effective method for continued operation of electrical equipment during voltage sag

This research focuses on mitigating voltage sags at control level through a cost-effective method using mini dynamic sag corrector at low voltage systems and proposing control level embedded solutions for equipment design and modifying the technical aspects of electrical devices to facilitate the control circuit to ride-through voltage sags. Voltage sags also known as "dips" are a common cause of power disturbances. These are temporary voltage drops below 90% of the nominal voltage caused by a sudden increase in loads or short circuits and faults lasting up to 170ms. Voltage sag in distribution networks can adversely affect sensitive electrical equipment in industrial processes, such as production and manufacturing resulting in substantial financial losses up to $1.5 million/day. Various types of electrical equipment are susceptible to voltage sags but not limited to power supplies, relays, contactors, variable frequency drives, and programmable logic controllers. In this method, the cost-effective MiniDySCs were installed in the industrial plant to compensate for the missing voltage in the lines during a sag event. Also, modifications to technical aspects of Contactors, Relays, and VFDs are proposed to provide more robust results for the control circuits to ride through voltage sags even up to 40% of nominal voltage drop. Keywords: Voltage Sag, Dynamic Sag Corrector, VFD, Power Quality