ABB Relion 670 series - Completing the Test; Four Step Negative Sequence Overcurrent Protection NS4 PTOC

15.6.4.3 Completing the test
Continue to test another function or end the test by changing the Test mode setting
to Off. Restore connections and settings to their original values, if they were
changed for testing purposes.
15.6.5 Four step negative sequence overcurrent protection
NS4PTOC
Prepare the IED for verification of settings as outlined in section "Overview" and
section "Preparing for test" in this chapter.
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 of utmost importance to set the definite time delay
for that stage to zero.
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 Ur) 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.
8. Set the injected current to 200 % of the operate level of the tested step, switch
on the current and check the time delay.
For inverse time curves, check the operate time at a current equal to 110 % of
the operate current in order to test parameter txmin.
9. Check that all trip and start contacts operate according to the configuration
(signal matrixes)
Section 15 1MRK 502 029-UEN A
Verifying settings by secondary injection
172
Installation and commissioning manual