Permissible Harmonics On The Supply Voltage - Siemens SINAMICS G130 Engineering Manual

Fundamental Principles and System Description
Engineering Information
Measures for the reduction of the effects of large and long supply voltage dips
Kinetic Buffering
Longer supply voltage dips of more than 50 ms and larger than 50 % of the nominal supply voltage V
to range F can, due to the more or less interrupted energy flow from the supply to the DC link, be bridged without a
fault trip only if the motor can provide energy to buffer the DC link. This is the case at drives with sufficiently large
rotating masses. In such cases, the kinetic buffering function can be used. This function is included as a standard in
the firmware of SINAMICS converters and inverters and can be activated by parametrization when required. During a
supply voltage dip, the kinetic buffering function takes energy from the rotating masses for the buffering of the DC link
and thus prevents a fault trip. After the supply voltage dip the rotating masses are accelerated again. This procedure
can be used if sufficiently large rotating masses are available in order to buffer the supply voltage dip for a long
enough time period and if the driven process can tolerate a reversal in the direction of energy flow during the supply
voltage dip. With sufficiently large rotating masses, very large supply voltage dips and even supply voltage failures
which last for several seconds can be bridged without a fault trip of the drive.
Automatic Re-Start in combination with Flying-Restart
At large and very long supply voltage dips in the range F, or at longer supply voltage failures, a fault trip is
unavoidable. This trip can be accepted in many applications, as long as the drive is able to re-start again by its own
after the voltage dip or voltage failure and as long as the drive is able to accelerate again to the original operating
condition. For this, the automatic re-start function can be used. If a re-start after a supply voltage dip is expected with
a rotating motor, the automatic re-start function must be combined with the flying re-start function. The flying re-start
function recognizes direction and speed of the rotating motor even without speed encoder at the motor and starts the
acceleration process beginning from the actual speed. The automatic re-start function and flying re-start function are
included as a standard in the firmware of SINAMICS converters and inverters and can be activated by
parametrization when required.

Permissible harmonics on the supply voltage

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.
Harmonic Number
h
5
7
11
13
17
17 < h ≤ 49
Compatibility level for harmonics, according to EN 61000-2-4
– 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) according to EN 61000-2-4
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.
Otherwise, components in the converter itself or the corresponding line-side components may be thermically
overloaded or error functions may occur in the converter.
Further information can be found in the section "Harmonic effects on the supply system", under the subsection
"Standards and permissible harmonics".
SINAMICS Engineering Manual – May 2008
32/396
© 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 %
corresponding
N
h