Are All Power Quality Problems Surges?
No, surges, or transients, do not explain all of the voltage-related power quality issues in the world today. • Drops in voltage that last a fraction of a second to as much as a few seconds are known as voltage sags. • Voltage drops that last several seconds or even minutes are known as brown outs. Both sags and brownouts are more damaging to motor loads than they are to microprocessor based equipment. • Sustained over-voltages are known as voltage swells and can last from a few seconds to several minutes. Sustained over-voltage conditions can be very damaging to many types of equipment, but are not nearly as frequent as transients or surges. Power outages are another type of power quality issue that can last from several seconds to hours or even days. Surge protective devices (SPDs), also known as transient voltage surge suppressors (TVSS), do nothing to prevent the harm that can be caused by power outages. Equipment can be protected from the damaging effects of power outages by utili
