IEC reset times from operated condition to fully reset are as follows for zero applied current and Time multi-
plier (Tm) = 1.0. The reset curve characteristic type and Tm is defined by the operating characteristic.
Curve Fully Operated to Reset with Zero Current Applied
& Tm = 1 (s)
IEC-NI 9.7
IEC-VI 43.2
IEC-EI 58.2
IEC-LTI 80
Apply current in the following sequence, a) 2 times setting for a time to ensure element operation, b) Zero
current for the reset time above (xTm), c) 2 times setting for a time to ensure element operation. Check that
the second operation (c) is similar to the first (a) and in line with the expected operate time for the element at
this current level.
Repeat the test with the reset time (b) reduced to 50 % of the previous value. Ensure that the second operate
time (c) is 50 % of the first (a) operate time.
Check correct indication, trip output, alarm contacts, waveform record.
50AFD Arc Flash Detection
The overcurrent level can be tested without an arc flash by separately energizing or inverting the arc detector
binary input continuously for the duration of the test for the zone being tested.
50AFD current threshold can be tested by single phase current injection on any of the 3 phase inputs. 50GAFD
current threshold can be tested by single phase current injection on the CT4 current input.
If the current setting is low, gradually increase current until element operates.
If the current level required is greater than the thermal limit of the relay, apply 0.9 times setting, check for no
operation, apply 1.1 times setting, check operation.
Optical sensors such as 7XG31 can be tested by application of a suitable light source. Relay instrumentation
can be used to indicate binary input pickup or by the 50AFD Zone-n Flash outputs.
The 7XG31 devices will typically require 10000 lx light level for 1.25 ms to trigger. A high powered photo-
graphic flash is the most convenient means of initiating positive sensor operation.
Note that mobile phone or small compact camera flashes may not have sufficient power to cause sensor oper-
ation but may be suitable if held directly against the sensor.
Check correct indication, trip output, alarm contacts, waveform record.
50G/51G Measured Earth Fault
Other protection functions may overlap with these functions during testing, it may be useful to disable some
functions to avoid ambiguity. Calculated EF, Measured EF, Sensitive EF & Restricted EF protec-
tions can be Enabled/Disabled individually or as groups in the Function Config menu.
Measured EF elements can be separated from Calculated EF and Sensitive EF by secondary injection
of current through the CT4 input circuit only.
If any of these elements are defined as directional the correct voltage phase direction will be required to
produce an operation of those elements.
Directional Polarity (67G)
See 10 Technical Data for testing details.
9.9.12
9.9.13
Functional Tests
9.9 Protection Functional Tests
476 Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019
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