Siemens SINAMICS S120 Combi - Page 54

Line-side power components
2.8 Line connection versions
SINAMICS S120 Combi
52 Manual, Edition 07/2012, 6SL3097-4AV00-0BP3
Example 4
If S
K plant
is lower, you can use, alternatively to example 3, a transformer with a lower u
k
.
u
k
matching transformer = 1 %,
S
K plant
= 3,000 kVA
S
K line
= 16 kW • 70 • 0.73 = 820 kVA
according to a)
S
n1
= 1.27 • 16 kW = 21 kVA
According to b)
N9$
N9$ವN9$ವ
N9$N9$ವ
6
Q

S
n1
> S
n2
⇒ S
n1
is decisive
The matching transformer requires a rated power S
n
of 21 kVA for a short-circuit voltage u
k
of 1%.
Note
S
n2
for the matching transformer can be reduced by reducing u
k
. In the examples listed
above, the power drawn from other loads has not been taken into account.