Power
failure or blackout: Is defined as
zero-voltage conditions that last for more
than two cycles.
The tripping of a circuit breaker,
power distribution failure or utility power
failure may cause it. This condition can
lead to data damage, data loss, and file
corruption and hardware damage.
Power sags:
Involve voltages 80 to 85 percent below
normal for a short period of time.
Possible causes are heavy equipment
being turned on, large electrical motors
being started, and the switching of power
mains.
A power sag can have effects similar
to those of a power surge, such as memory
loss, data errors, flickering lights and
equipment shutoff.
Power surge:
Takes place when the voltage is 110%
above normal. The most common cause is heavy
electrical equipment being turned off.
Under this condition computer systems
may experience memory loss, data errors,
flickering lights, and equipment shutoff.
A brownout:
Is a steady lower voltage state. An example
of a brownout happens during peak electrical
demands in the requirements and must lower
the voltage to limit maximum power. When
this happens, computer systems can
experience data corruption, data loss and
premature hardware failure.
Over
Voltage: Increase line voltage for
extended periods of a few minutes to a few
days
Electrical line noise: Is
defined as Radio Frequency
Interference and Electromagnetic
Interference and causes undesirable
effects in the circuits of computer
systems.
Sources of the problem
include electric motors, relays,
motor control devices, broadcast
transmissions, microwave radiation
and distant electrical storms. They
can cause data error, data loss,
storage loss, keyboard lockup and
system lockup.
A frequency
variation: Involves a
change in frequency from the
normally stable utility
frequency from the normally
stable utility frequency of
50 Hz or 60 Hz, depending on
the geographic location.
This may caused by
erratic operation of
emergency generators or
unstable frequency power
sources.
For sensitive
electronic equipment, the
result can be data
corruption, hard drive
crash, keyboard lockup and
program failure.
Switching
transients:
Takes place when
there is a rapid
voltage peak of up
to 20,000 volts with
a duration of 10
microseconds to 100
microseconds. They
are commonly caused
by arcing faults and
static discharge, in
addition, major
power system
switching
disturbance
initiated by the
utilities to correct
line problems may
happen several times
a day. Effects can
include memory loss,
data error, and data
loss and component
stress.
Harmonic Distortion: Distortion of the normal waveform generally
transmitted by nonlinear loads.
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