Completing The Test; Four Step Negative Sequence Overcurrent Protection Ns4Ptoc - ABB RELION 670 Series Commissioning Manual

1MRK 505 345-UEN B
1. Do as described in
any polarizing voltage.
10.5.4.3

Completing the test

Continue to test another function or end the test by changing the
Restore connections and settings to their original values, if they were changed for testing
purposes.
10.5.5

Four step negative sequence overcurrent protection NS4PTOC

Prepare the IED for verification of settings as outlined in section
section
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 (
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
9. Check that all operate and start contacts operate according to the configuration (signal
matrixes)
10. Reverse the direction of the injected current and check that the step does not operate.
11. Check that the protection does not operate when the polarizing voltage is zero.
12. Repeat the above-described tests for the higher set steps.
13. Finally, check that start and trip information is stored in the event menu.
Commissioning manual
"Four step directional earth fault
"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 important to set the
definite time delay for that stage to zero.
Testing functionality by secondary injection
protection", but without applying
txmin .
Section 10
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TestMode setting to Off .
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"Requirements" and
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