Date Code 20010731
Testing and Troubleshooting
11-19
SEL-352-1, -2 Instruction Manual
F
AULT
C
URRENT
B
REAKER
F
AILURE
, S
CHEME
2 L
OGIC
T
EST
Purpose: Verify operation of the Scheme 2 fault current breaker failure logic (Reference:
Figure 3.8).
Method: 1. While the relay is capable of employing five different fault current breaker failure
schemes, only one is enabled at a time. Select Scheme 2 by setting FTLOG = 2 in
the relay setting group. Using the
SET
command, set an output to close when the
FBF element asserts, and set the SER to trigger for the TRIPA, 50FT, and FBF
elements. Verify the settings with the
SHO
command, and verify the
SHO G
command for TRIPA.
Setting
Elements
FTLOG, 50FT,
FCpu, TRIPA
50FT, FBF
2. Connect an external timer and set it to start when the TRIPA input asserts and stop
when the programmable output you set in Step 1 asserts.
3. Apply A-phase current above the 50FT setting. The relay should generate an
event report.
4. Assert the TRIPA input. This action causes the relay to start its 62FC timer. The
external timer should also start.
5. Shortly after the TRIPA input asserts, the programmable output contact set in Step
1 should close, indicating FBF bit assertion. This action should stop the external
timer. Record the timer reading. It should be close to the FCpu setting.
6. Deassert the TRIPA input, and shut off A-phase current.
7. This step is optional. To test Scheme 2 logic operation under conditions that
could represent normal relay/breaker operation, repeat Steps 3 and 4. This time,
turn off A-phase current 1.5 to 2.0 cycles before the 62FC timer expires. The FBF
bit should not assert.
8. Repeat Steps 3, 4, 5, 6, and 7 (optional) for phases B and C.
9. For each test the relay generated a sequential events record for the elements
programmed in Step 1. View the SER using the
SER
command. These time
stamps will also verify the FCpu timer. The time between TRIPA being asserted
and FBF being asserted should be about the same as the FCpu setting.
F
AULT
C
URRENT
B
REAKER
F
AILURE
, S
CHEME
3 L
OGIC
T
EST
Purpose: Verify operation of the Scheme 3 fault current breaker failure logic (Reference:
Figure 3.10).
Method: 1. While the relay can use five different fault current breaker failure schemes, only
one is enabled at a time. Select Scheme 3 by setting FTLOG = 3 in the relay
setting group. Using the
SET
command, set an output to close when the FBF
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