RFL 9300 RFL Electronics Inc.
October 20, 2004 7 - 20 (973) 334-3100
3. Continue to increase the test current.
At 3 amperes, the LCCT alarm will occur on Phase A. This is because a received WCM
activates the Strong Feed Trip (SFT) logic. The received WCM is treated as a received
charge comparison data message with a current value of zero.
At 3 amperes in Phase A at the left terminal, the arithmetic sum is 3 amperes. This sat-
isfies the bias setting and creates an LCCT alarm condition, since the Phase A fault de-
tector does not operate.
4. Return the test current to zero and suddenly apply a 3-ampere current.
Tripping will occur at both relays, and the TRIP 1, and A and G target indicators on both
relays will light.
7.4.12 OTHER INTERNAL FAULT TYPES WITH REMOTE BREAKER OPEN (optional)
The test circuit shown in Figure 7-11 may be modified to simulate the other fault types. The results obtained
with B-G and C-G faults should be similar to those obtained with the A-G fault. For phase-to-phase and three-
phase faults, the LCCT alarm will occur at 3 amperes if the current is increased gradually. If the 3-ampere test
current is applied suddenly, tripping will occur, with appropriate phase targets.
7.4.13 BACKUP TRIPPING WITH HIGH-SET OVERCURRENT
The backup tripping modes (high-set overcurrent/loss-of-load/switch-into-fault) become operative if the re-
ceived channel signal is lost and
Parameter #27 (BACKUP) is enabled (See paragraph 3.13 for more informa-
tion). The following procedure describes the testing of the high-set overcurrent function. The loss-of-load and
switch-into-fault tripping modes are more difficult to test, and are beyond the scope of this procedure.
1. Temporarily lower the phase and ground backup settings to levels that are easy to test (such as 10
amperes phase and 7 amperes ground).
2. Connect the relays for an external A-G simulation. (See Figure 7-2)
3. Disable the channel in either direction.
Both relays will go into a BACKUP ENABLE condition, and both red BACKUP indica-
tors will light.
4. Increase the test current.
At the ground overcurrent backup setting (7 amperes), both relays should trip on G and
the TRIP 1 and G target indicators on both relays will light. At 10 amperes, both relays
should trip on Phase A and the A target indicators on both relays should light.
5 (optional).
Test the other phases to verify the backup high-set overcurrent tripping level.
6. Return the overcurrent backup settings to the default values (31.87 amperes phase and 31 amperes
ground).
If two synchronized ac current sources are available, with the phase angle between test currents adjustable,
tests may be done to demonstrate the "rainbow" characteristic, "Delay Measurement Based On Load" (DML)
and "outfeed." These optional tests are described in the next three procedures.
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