Siemens SINAMICS S120 - Line Reactors

SINAMICS S120 Cabinet Modules
Engineering Information
SINAMICS Engineering Manual – November 2015
Ó Siemens AG
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7.2.2.7 Line reactors
Line reactors are installed in conjunction with Basic Line Modules (v
k
= 2 %) or Smart Line Modules (v
k
= 4 %).
A line reactor must be installed whenever
· the rectifiers are connected to a line supply system with high short-circuit power, i.e. with low line supply
inductance,
· more than one rectifier is connected to the same point of common coupling (PCC),
· the rectifiers are equipped with line filters for RFI suppression,
· the rectifiers are operating in parallel to achieve a higher output power.
The line reactor smoothes the current drawn by the rectifier, thereby reducing harmonics in the line current and thus
the thermal load on the DC link capacitors of the rectifier. The harmonic effects on the supply are also reduced, i.e.
both the harmonic currents and harmonic voltages in the power supply system are attenuated.
Line reactors can be dispensed with only if the supply cable inductance is sufficiently high or the relative short-circuit
power RSC
*)
correspondingly low.
The following values apply to Basic Line Modules:
BLM output Line reactor can be omitted Line reactor required
kW
for an RSC of Option Code for an RSC of
< 200 ≤ 43 L22 for relev. LCM > 43
200 bis 500 ≤ 33 L22 for relev. LCM > 33
> 500 ≤ 20 L22 for relev. LCM > 20
The following values apply to Smart Line Modules:
SLM output Line reactor can be omitted Line reactor required
kW for an RSC of
Option Code
for an RSC of
≥ 250 ≤ 12,5 L22 for relev. LCM > 12,5
As the configuration of the supply system for operating individual Basic Line Modules or Smart Line Modules is often
not known in practice, i.e. the short-circuit power at the PCC is not known, it is advisable to connect a line reactor in
cases of uncertainty.
A line reactor can only be dispensed with when the RSC values for relative short-circuit power are lower than those
stated in the above table. This applies, for example, if the Basic Line Module or the Smart Line Module is connected
to the supply via a transformer with specially adapted rating and none of the other reasons stated above for using a
line reactor is valid.
*)
RSC = Relative Short-Circuit Power according to EN 60146-1-1:
Ratio between the short-circuit power S
K Line
of the supply system and the rated apparent power (fundamental apparent power)
S
converter
of the converter at its point of common coupling