08-09-2016, 12:10 PM
Voltage Sag or Voltage Dip (IEC term) is defined by the IEEE 1159 as the decrease in the RMS voltage level to 10% - 90% (1% - 90% for EN 50160) of nominal, at the power frequency for durations of ½ cycle to one (1) minute. Also, voltage sag is classified as a short duration voltage variation phenomena, which is one of the general categories of power quality problems.
Voltage sag (dip) durations are subdivided into three categories: instantaneous (½ cycle to 30 cycles), momentary (30 cycles to 3 seconds), and temporary (3 seconds to 1 minute). These durations are intended to correlate with typical protective device operation times as well as duration divisions recommended by international technical organizations. Sags are widely recognized as among the most common and important aspects of power quality problems affecting commercial and industrial customers - they are virtually unnoticeable by observing lighting blinks but many industrial processes would have shutdown. Possible effects of voltage sags would be system shutdown or reduce efficiency and life span of electrical equipment, specifically motors. Therefore, such disturbances are particularly problematic for industry where the malfunction of a device may result in huge financial losses.
Voltage sag (dip) durations are subdivided into three categories: instantaneous (½ cycle to 30 cycles), momentary (30 cycles to 3 seconds), and temporary (3 seconds to 1 minute). These durations are intended to correlate with typical protective device operation times as well as duration divisions recommended by international technical organizations. Sags are widely recognized as among the most common and important aspects of power quality problems affecting commercial and industrial customers - they are virtually unnoticeable by observing lighting blinks but many industrial processes would have shutdown. Possible effects of voltage sags would be system shutdown or reduce efficiency and life span of electrical equipment, specifically motors. Therefore, such disturbances are particularly problematic for industry where the malfunction of a device may result in huge financial losses.
