There are nine distinct types of power problems
and three basic levels of power protection

The 9 types of power problems are:

  1. Power Failure
  2. Power Sag
  3. Power Surge
  4. Undervoltage
  5. Overvoltage
  6. Electrical Line Noise
  7. Frequency Variation
  8. Switching Transient
  9. Harmonic Distortion

The levels of power protection are:

  1. Level 3
  2. Level 5
  3. Level 9

1. Power Failure - A total loss of utility power.
It can lead to hardware damage, data loss, or total system crashes and can be caused by a number of events:

  • lightning strikes;
  • downed power lines;
  • grid over demands;
  • tripped facility breakers;
  • accidents; or,
  • natural disasters.
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2. Power Sag - Short-term low voltage.
Similar to power failures, sags can damage the hardware and can be triggered by:

  • the startup of large loads;
  • utility switching;
  • utility equipment failure;
  • lightning; or.
  • power service that is too small for the demand.
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3. Power Surge - Also known as a Spike.
Short-term high voltage above 110% of nominal. The results can potentially damage hardware. With voltages above 110% of nominal, surges can be triggered by:

  • a rapid reduction in power loads;
  • heavy equipment being turned off; or,
  • utility switching.
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4. Undervoltage - Also known as a Brownout.
Reduced line voltage for extended periods of a few minutes to a few days. Undervoltage can lead to equipment failure. Can be caused by:

  • an intentional utility voltage reduction to conserve power during peak demand periods; or,
  • other heavy loads that exceed supply capacity.
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5. Overvoltage - Increased line voltage for extended periods of a few minutes to a few days.
Overvoltage almost always results in data loss or hardware damage. Can be caused by a lightning strike and can send line voltages to levels in excess of 6,000 volts.
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6. Electrical Line Noise - High frequency waveform caused by RFI or EMI interference.
Introduces glitches and errors into programs/files as well as damaging hardware components. Can be caused by either RFI or EMI interference generated by;

  • transmitters;
  • welding devices;
  • SCR driven printers;
  • lightning; or,
  • a variety of other electrical disturbances.
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7. Frequency Variation - A change in frequency stability.
This often results from generator or small co-generation sites being loaded and unloaded. Frequency variation can cause:

  • erratic operation;
  • data loss;
  • system crashes; or,
  • equipment damage.
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8. Switching Transient - Instantaneous ender voltage (notch) in the range of nanoseconds.
Normal duration is shorter than a spike and generally falls in the range of nanoseconds. Can result in quirky computer behavior and puts stress on components which can lead to premature failure.
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9. Harmonic Distortion - Distortion of the normal waveform generally.
Can cause communication errors, overheating and hardware damage. Examples of non-linear loads that can cause this condition are:

  • Switch mode power supplies;
  • variable speed motors and drives;
  • copiers; and.
  • fax machines.
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