Frequency distortions/fluctuating
A frequency variation involves variation in frequency above or below the normally stable utility frequency of 50 or 60 Hz
Cause
Cause
- Start-up or shutdown of very large item of consumer equipment, e.g. motor
- Unstable frequency power source
- Miss operation, data loss, system crashes and damage to equipment and motor
- For certain kinds of motor load, such as in textile mills, tight control of frequency is essential
Voltage dip / sag or swell
Any short-term (half cycle to 3 seconds) decrease (sag) or increase (swell) in voltage
Cause
Cause
- Start-up or shutdown of very large item of consumer equipment, e.g. motor
- Short circuits (faults)
- Utility equipment failure or utility switching
- Memory loss, data errors, dim or bright lights, shrinking display screens, equipment
- Shutdown
- Motors stalling or stopping and decreased motor life
Flicker
Flicker is a periodically repeated voltage fluctuation = Impression of unsteadiness of visual sensation induced by a light stimulus, the luminance or spectral distribution of which fluctuates with time.
Cause
Changes in the luminance of lamps can result in the visual phenomenon called flicker on people, disturbing concentration, causing headaches, etc.
Cause
- Intermittent loads
- Motor starting
- Welding plants
Changes in the luminance of lamps can result in the visual phenomenon called flicker on people, disturbing concentration, causing headaches, etc.