Verifying The Settings - ABB RED670 Commissioning Manual

1MRK 505 378-UUS Rev. J
current in phase C is returned in phase A. The magnitude of the returned current can be set separately
as a ratio of the injected current.
Take a line with three IEDs, for example, set the return current from each remote IED to be 50% of the
injected current. Inject a current I in phase A to get the following differential and bias currents:
Phase A:
=
IDiff
A
EQUATION1821-ANSI V1 EN-US
Phase B:
=
IDiff
B
EQUATION1822-ANSI V1 EN-US
Phase C:
=
IDiff
B
EQUATION1823-ANSI V1 EN-US
11.3.4.1

Verifying the settings

Procedure
1. Block the trip signal from all involved IEDs with local operation released. See below.
2. Set Test mode to Enabled for the Line differential function for test.
3. Release the local function with setting ReleaseLocal in local HMI under: Main menu /Test /Line
differential test /LineDiffLogic
4. Set the factor of the return currents to 1/(number of current IEDs = 1).
5. Inject a current in phase A and increase the current until the function operates for phases A and B.
The injected trip current must correspond to the set IdMin. The service values for IDiff_A, IBias_A,
IDiff_B and IBias_B must be equal to the injected current.
6. Repeat step
7. Inject a symmetrical three-phase current, and increase the current until operation is achieved in all
three phases.
The injected trip current must correspond to the set IdMin. The service values for IDiff_A, IBias_A,
IDiff_B, IBias_C, IDiff_C and IBias_C must be equal to the injected current.
8. Read the transmission delay.
9. Measure the operating time by injection of a single-phase current in phase A.
The injected current must be 4 times the operating current. The time measurement is stopped by
the trip output.
Note that tripping times at this loop test includes sending the local currents to remote side and with
a factor sending them back. This means that tripping times are virtually double to the times
achieved at a real fault or at bench testing.
10. Check the negative sequence fault discriminator by injecting a three-phase current with changed
phase sequence: switch phases A and B. The injected current will now be seen as a pure negative-
sequence current where the phase angle between the local negative-sequence current and the
remote negative-sequence currents will be 120°.
With the current above IMinNegSeq, the signal external fault (EXTFAULT) must apply. No trip must
be generated.
11. Disconnect the test equipment and reconnect the current transformers.
Line differential protection RED670
Commissioning manual
=
IBias I
A injected A ,
= × Ð °
IBias I 1 240
B injected A ,
=
IBias 0
B
4 by current injection in phases B and C.
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Section 11
Testing functionality by secondary injection
SEMOD56264-69 v4
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