The effects of harmonics are described here only in the
context of the analytical harmonic system study, details of these effects can
be found in referenced literature. IEEE Std 519-1992 (Chapter 6) and
Prabhakara, Smith, and Stratford [B30] (Chapter 5) deal with the subject in
detail.
The effects of harmonics in a power system are pervasive in
that they influence system losses, system operation, and system performance.
Unless the harmonics are controlled to acceptable limits, the power equipment
and, even more so, the electronic equipment may be damaged resulting in and
costly system outages.
The effects of harmonics are due to both current and
voltage, although current-produced effects are more likely to be seen in
day-to-day performance. Voltage effects are more likely to degrade the
insulation and hence shorten the life of the equipment.
The following describes some of the common effects of
harmonics:
a) Increased losses within the equipment and associated
cables, lines, etc.,
b) Pulsating and reduced torque in rotating equipment,
c) Premature aging due to increased stress in the equipment
insulation,
d) Increased audible noise from rotating and static
equipment,
e) Misoperation of equipment sensitive to waveforms,
f) Substantial amplification of currents and voltages due to
resonances, and
g) Communication interference due to inductive coupling
between power and communication
circuits.
Generally, harmonic studies involving harmonic flows and
filter design do not involve detailed analysis of the effects of harmonics if
the limits imposed by the user or by a standard are met.
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