A few common causes of power quality issues are:
- Voltage Sags (10% -90% voltage reduction for less than 1 minute)
- Voltage Swells (110% or greater increase of voltage for less than 1 minute)
- Bad grounding
- Bad neutral connection
- Harmonic distortion
- Equipment switching on or off
- Failing equipment
Most power quality issues are created from some piece of equipment, however it can be difficult to find the source of the problem.