Restricted Earth-Fault Protection, Low Impedance Refpdif (87N); Verifying The Settings; Completing The Test; Additional Security Logic For Differential Protection Ldrgfc (11) - ABB RET670 Commissioning Manual

1MRK 504 154-UUS B
10.3.3

Restricted earth-fault protection, low impedance REFPDIF (87N)

Prepare the IED for verification of settings as outlined in section
section "Preparing for test"
10.3.3.1

Verifying the settings

1. Connect the test set for single-phase current injection to the protection terminals connected
to the CT in the power transformer neutral-to-ground circuit.
2. Increase the injection current and note the operating value of the protection function.
3. Check that all trip and pickup contacts operate according to the configuration logic.
4. Decrease the current slowly from operate value and note the reset value.
5. Connect the timer and set the current to ten times the value of the IDMin setting.
6. Switch on the current and note the operate time.
7. Connect the test set to terminal A and neutral of the three-phase current input configured to
REFPDIF (87N). Also inject a current higher than half the
ground circuit with the same phase angle and with polarity corresponding to an internal
fault.
8. Increase the current injected in A, and note the operate value. Decrease the current slowly
and note the reset value.
9. Inject current into terminals B and C in the same way as in step 7 above and note the operate
and reset values.
10. Inject a current equal to 10% of rated current into terminal A.
11. Inject a current in the neutral-to-ground circuit with the same phase angle and with polarity
corresponding to an external fault.
12. Increase the current to five times the operating value and check that the protection does not
operate.
13. Finally check that trip information is stored in the event and disturbance recorder.
10.3.3.2

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.
10.3.4

Additional security logic for differential protection LDRGFC (11)

10.3.4.1 Verifying the settings
Prepare the IED for verification of settings outlined in section 1 "Overview" and section 2
"Preparing for test" in this chapter.
Current variation local criteria
Procedure
1. Set
2. Connect the test set for three phase current injection to the appropriate IED terminals.
3. Inject symmetrical phase currents equal to half the rated current
Commissioning manual
in this chapter.
Operation to Enabled .
Testing functionality by secondary injection
"Requirements" and
Idmin setting in the neutral-to-
TestMode setting to Disabled .
GUID-0E064528-0E70-4FA1-87C7-581DADC1EB55 v2
GUID-D9F626D4-4038-416F-888E-D3DB5047E79A v1
GUID-804E13B6-DC31-487B-A582-7886B1EF3EB7 v2
Section 10
SEMOD55252-82 v7
SEMOD55252-86 v10
SEMOD55252-118 v5
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