BENNING IT 115
Device description
- 44 -
5.6.1 Line impedance and prospective short-circuit current
Connection plan
Figure 5.28
:
Connection of the optional "Commander" test plug (044149)
and the three-wire test cable
How to perform line impedance measurements
Select the
Z
I
(L-N/L)
[English: Z
LINE
(L-N/L)] function by means of the function selector
switch.
Set the sub-function to
Zline
.
Set the testing parameters.
Connect the test cables to the test object (see figure 5.28).
Press the "
TEST
" key to start the measurement.
x
Figure 5
.29
: Example of a line impedance measurement
Results displayed:
Z
............... line impedance
Isc
............ prospective short-circuit current
Lim
........... lower limit of the prospective short-circuit current
The prospective short-circuit current is calculated as follows:
Z
k
Un
I
SC
SC
with:
Un .......nominal voltage L-N or L1-L2 (see table below),
ksc ......correction factor for short-circuit current Isc (see chapter
4.4.6 Isc factor (scaling factor)
)
U
n
Voltage range (L-N or L1-L2)
110 V (93 V
U
L-N
134 V)
230 V (185 V
U
L-N
266 V)
400 V (321 V
U
L-L
485 V)
