11.5.4.2 Four step non-directional earth fault protection
SEMOD53296-202 v4
1. Do as described in "Four step directional earth fault protection", but without
applying any polarizing voltage.
11.5.4.3 Completing the test
SEMOD53296-122 v4
Continue to test another function or end the test by changing the TESTMODE
setting to Off
. Restore connections and settings to their original values, if they were
changed for testing purposes.
11.5.5 Four step negative sequence overcurrent protection
NS4PTOC
GUID-EB1A8DFD-5BAC-4024-ADA2-D9BE7A2B50A0 v2
Prepare the IED for verification of settings as outlined in section
"Preparing for
test" in this chapter.
GUID-F7AA2194-4D1C-4475-8853-C7D064912614 v4
When inverse time overcurrent characteristic is selected, the
operate time of the stage will be the sum of the inverse time delay
and the set definite time delay
. Thus, if only the inverse time delay
is required, it is important to set the definite time delay for that
stage to zero.
GUID-F973601F-BC67-4E4F-A4CA-BE6253E2FB92 v3
Procedure
1. Connect the test set for injection of three-phase currents and voltages to the
appropriate CT and VT inputs of the IED.
2.
Inject pure negative sequence current, that is, phase currents with exactly
same magnitude, reversed sequence and exactly 120° phase displaced into the
IED with an initial value below negative sequence current pickup level. No
output signals should be activated. Check under NS4PTOC function Service
Values that correct I2 magnitude is measured by the function.
3. Set the injected negative sequence polarizing voltage slightly larger than the
set minimum polarizing voltage (default 5 % of Ub) and set the injection
current to lag the voltage by an angle equal to the set reference characteristic
angle (180° - AngleRCA) if the forward directional function is selected.
If reverse directional function is selected, set the injection current to lag the
polarizing voltage by an angle equal to RCA.
4. Increase the injected current and note the value at which the studied step of
the function operates.
5. Decrease the current slowly and note the reset value.
6. Block lower set steps when testing higher set steps according to the
instructions that follow.
7. Connect a trip output contact to a timer.
Section 11 1MRK 505 378-UEN A
Testing functionality by secondary injection
176 Line differential protection RED670 2.2 IEC
Commissioning manual
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