Siemens SINAMICS G130 Engineering Manual page 48

Fundamental Principles and System Description
Engineering Information
EN 61000-2-4 does not define limits for harmonic currents. Limits are specified only for harmonic voltages and the
total harmonic distortion of the voltage THD(V).
Harmonic number
h
5
7
11
13
17
17 < h ≤ 49
Compatibility levels for harmonics
– harmonic contents of the voltage V, odd harmonics, no multiples of 3
Total Harmonic Distortion factor
THD(V)
Compatibility levels for the Total Harmonic Distortion factor of the voltage THD(V)
The following is a rough guide to the supplementary conditions under which the limits can be maintained in
accordance with EN 61000-2-4:
•
When using 6-pulse rectifier circuits (G130, G150, S120 Basic Line Modules and S120 Smart Line Modules), the
limits of Class 2 can generally be maintained when 30 % to maximum 50 % of the total transformer load is made
up of converter load. The limits of Class 3 are generally also maintained even with almost 100 % converter load.
•
When using 6-pulse rectifier circuits (G130, G150) with Line Harmonics Filters, the limits of Class 2 can generally
be maintained independent from what percentage of the transformer load is attributable to the converter.
•
When using 12-pulse rectifier circuits (G150 in the higher power range with two parallel connected converters or
S120 Basic Line Modules or S120 Smart Line Modules supplied by a three-winding transformer), the limits of
Class 2 can also be maintained.
•
When self-commutated IGBT infeeds (S150, S120 Active Line Modules) are used, the limit values of class 2 can
always be maintained. Under normal supply system conditions, the limit values of class 1 can also generally be
maintained.
If a large number of 6-pulse rectifier circuits are used, an exact calculation of the harmonic effects on the supply
should always be performed with the supplementary conditions of the individual plant constellation.
SINAMICS converters and the corresponding line-side system components (line reactors, Line Harmonics Filter and
line filters) are designed for being connected to supplies with a permanent level of voltage harmonics, according to
EN 61000-2-4, Class 3. In the short-term (< 15 s within a time period of 2.5 min) a level of 1.5 times the permanent
level is permissible.
That means that no voltage harmonics higher than those given in the table under Class 3 may appear at the
connection point for SINAMICS units. This includes harmonics produced by the units themselves. This must be
guaranteed by means of correct engineering. If necessary, Line Harmonics Filters, 12-pulse solutions or Active
Infeeds may be used to stay within the limits of Class 3.
The values according to EN 61000-2-4, Class 3, must be observed not only for the protection of other equipment
connected to the PCC, but also for the protection of the SINAMICS units themselves. Otherwise, components in the
converter itself or the corresponding line-side components may be thermically overloaded or error functions may
occur in the converter.
SINAMICS Engineering Manual – May 2008
48/396
© Siemens AG
Class 1
V
h
%
3
3
3
3
2
2.27 x (17/h) – 0.27 2.27 x (17/h) – 0.27
Class 1
5 %
Class 2 Class 3
V V
h
% %
6 8
5 7
3.5 5
3 4.5
2 4
4.5 x (17/h) - 0.5
Class 2 Class 3
8 % 10 %
h