Are you having problems with your appliances, or have you noticed any of the following?
- Your digital clocks flash 12:00
- The ground-fault circuit-interrupter (GFCI) in your bathroom keeps tripping for no apparent reason
- Frequent failures of home entertainment equipment, which you suspect are caused by "power surges"
- Every time your air conditioner turns on, the lights flicker.
Events like these can result from reliability or power quality issues. They may originate from the utility system, your home, or even the affected equipment itself.
Most power outages or disturbances are caused by events beyond the control of a utility. Common sources of disturbances (see illustration) include the following:
- Lightning
- Insulator flashovers
- Digging on underground lines
- Automobile collisions
- Birds, squirrels and other wildlife
- Trees and vegetation
- Strong winds
- Vandalism
- Equipment failures
- Switching and maintenance
Common sources of power disturbances
