Fault-Current (Fi-Rcd) Circuit-Breaker Test - LEM SATURN 100 plus Manuel D'utilisation

Measuring

3.7 Fault-Current (FI-RCD) Circuit-Breaker Test

The measuring function FI-RCD serves for checking the protective measure „fault-
current protection circuit". Nominal fault currents I of 10 mA, 30 mA, 100 mA, 300
DN
mA, 500 mA and 1000 mA may be selected and tripping measurements of the RCD
with 1x I ∆N , 2x I ∆N S , 5x I ∆N or increasing test current for determining the tripping
current may be carried out (ramp function = 13 increments of 300 ms each from 35
% to 95 % of I ∆N & 3 increments of 500 ms each from 100 ... 110 % of I ∆N .) For
voltages „U " < 152 V, the range 1000 mA is automatically assigned the function
L-PE
„without tripping". The voltages measured are the contact voltage „U ", the
L
earth/ground-connection resistance „R " and/or the loop resistance „R ", as well as
A S
the tripping time „t " and the tripping current „I A " with selection of the increasing
A
test current.
In all current ranges determination of the contact voltage and of the
earth/ground-connection resistance or loop resistance is also possible
without tripping the FI circuit breaker.
The measurement is done with 35% of the set nominal fault current and all values
are automatically computed to the full nominal fault current. When measuring with
resolution, the current is interrupted for safety reasons after 500 ms (with 1x I ∆N
and with 2x I ∆N S ) or after 300ms (with ramp) or after 150ms (with 5x I ∆N ),
provided that the RCD-circuit-breaker is not tripped.
All measurements may be performed with probe, for determining fault voltage
and earth/ground-connection resistance, or without probe, for measurement
of contact voltage and loop resistance.
If a probe is used, any noise voltages up to 20 V, occurring between the PE-
connection and the probe are automatically acquired and taken into account. They
can be displayed and do not falsify the result of measurement.
If the noise voltage exceeds 20 V, no measurement is performed, and the noise
voltage is displayed. The probe should then be repositioned so that the voltage
drops below 20 V. Because of the measuring method employed, even very high
probe contact resistances up to 10 kOhm may be neglected and will not falsify the
result of measurement (automatic check of the probe resistance at the start of a
measurement).
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