Question

Which event is the short reduction in the RMS voltage between 0.1 to 0.9 pu for a duration of 0.5 cycle to 1 minute?
1. Voltage sag
2. Voltage surge
3. Voltage interruption
4. Voltage degradation

Answer 1

Correct Answer - Option 1 : Voltage sag

Voltage sag is the short reduction in the RMS voltage between 0.1 to 0.9 pu for a duration of 0.5 cycle to 1 minute.

Voltage sag:

• Voltage sag is defined as a decrease in RMS voltage magnitude lasting from 0.5 to 30 cycles.
• It is also described as a short duration voltage decrease.
• The IEC definition for this phenomenon is dip.
• Voltage sags are usually associated with system faults but can also be caused by energization of heavy loads or starting of large motors.