MI 3101 EurotestAT: Measurements
Line impedance / Voltage drop
61
5.5.1 Line impedance and prospective short circuit current
Circuit for measurement of line impedance
L1
L2
L3
N
PE
R
E
Ro
L
PE
N
L/L
1
N/L2
PE/L3
N/
L
2
L
/L
1
PE
/L
3
Figure 5.23: Phase-neutral or phase-phase line impedance measurement – connection of
plug commander and universal test cable
Line impedance measurement procedure
Select the
Z-LINE
function.
Select the
Z
sub-function.
Select test
parameters
(optional).
Connect
test cable to the instrument.
Connect
test leads to the tested object (see
figure 5.23
).
Press the
TEST
key.
After the measurement is finished
store
the result (optional).
Line to neutral
Line to line
Figure 5.24: Examples of line impedance measurement result
Displayed results:
Z ..............Line impedance,
I
SC
............Prospective short-circuit current,
R..............Resistive part of line impedance,
XL............Reactive part of line impedance.
Prospective short circuit current is calculated as follows:
Z
k
Un
I
SC
SC
where:
Un ........Nominal L-N or L1-L2 voltage (see table below),
