ABB ACH580-31 - Calculating the Short-Circuit Current of the Installation; Calculation Example

￭
Calculating the short-circuit current of the installation
Make sure that the short-circuit current of the installation is at least the value
given in the fuse table.
The short-circuit current of the installation can be calculated as follows:
I
k2-ph
=
2 ·
R
c
2
+ (Z
k
+ X
c
)
2
U
where
Short-circuit current in symmetrical two-phase short-circuit I
k2-ph
Network line-to-line voltage (V) U
Cable resistance (ohm) R
c
Z
k
= z
k
· U
n
2
/ S
n
= transformer impedance (ohm) Z
k
Transformer impedance (%) z
k
Transformer rated voltage (V) U
n
Nominal apparent power of the transformer (kVA) S
n
Cable reactance (ohm) X
c
Calculation example
Drive:
• ACH580-31-145A-4
• supply voltage = 410 V
Transformer:
• rated power S
n
= 600 kVA
• rated secondary voltage (supply for drive supply) U
n
= 430 V
• transformer impedance z
k
= 7.2%
Supply cable:
• length = 170 m
• resistance/length = 0.398 ohm/km
• reactance/length = 0.082 ohm/km.
Technical data 181