The negative effect of harmonics is twofold
•
Harmonic currents contribute to system losses (in
cabling and transformer).
•
Harmonic voltage distortion causes disturbance
to and increases losses in other loads.
Non-linear
Current
Voltage
System
Impedance
Disturbance to
other users
Contribution to
system losses
130BB541.10
Illustration 2.5 The Negative Effect of Harmonics
2.2 Harmonic Mitigation Standards and
Requirements
The requirements for harmonic limitation can be:
•
Application-specific requirements.
•
Requirements from standards that have to be
observed.
2.2.1 Application-specific Requirements
The application-specific requirements are related to a
specific installation where there are technical reasons for
limiting the harmonics.
Example
Two 110 kW motors are connected to a 250 kVA
transformer. One motor is connected direct online, and the
other is supplied through a frequency converter. If the
direct online motor should also be supplied through a
frequency converter, the transformer is, in this case,
undersized. To retrofit without changing the transformer,
mitigate the harmonic distortion from the 2 frequency
converters by using VLT
®
Advanced Harmonic Filters
AHF 005/AHF 010.
2.2.2 Harmonic Mitigation Standards
There are various harmonic mitigation standards,
regulations, and recommendations. Different standards
apply in different geographical areas and industries. The
following encountered standards are presented:
•
IEC/EN 61000-3-2
•
IEC/EN 61000-3-12
•
IEC/EN 61000-3-4
•
IEC 61000-2-2
•
IEC 61000-2-4
•
IEEE 519
•
G5/4
Introduction to Harmonics a...
VLT
®
Advanced Harmonic Filter AHF 005/AHF 010
12
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MG80C602
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2
Summary of Contents for AHF 010
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