Date Code 20080110 Testing and Troubleshooting 10-21
SEL-387E Instruction Manual
Change the angle of IAW1 to zero degrees, or any value within about ±80
degrees of IAW3. The REF element should function. Verify this as
follows:
Execute the
TAR 38
command again. 50G3 should still be 1, REFP
should be 1 (indicating time out), 32IR should be 0, and 32IF should be 1
(indicating an internal, or forward, fault).
Step 4.
Purpose: Verify the operation time.
Method: Type
SER <Enter>
to view the SER records. The assertion and
deassertion of each element listed in the SER1, 2, 3, and 4 settings is
recorded. Subtract the time of assertion of the directional element (32IF)
from the assertion time of the time-out bit (REFP). This is the operate
time, which should be about one second, as calculated above. (50G3 will
have remained asserted from earlier in the test, since no change was made
to the IAW3 current.)
SER C
clears the SER records.
Step 5.
Purpose: Verify relay operation for faults with high neutral current but a small
difference in phase current.
Method: Clear the SER by typing
SER C <Enter>
. Connect a single current
source to phase IAW3. Set both current magnitude and phase angle to
zero. Change the 32IOP setting to 12. Type
TAR 32IE 9999
and confirm
that the status of the 32IE Relay Word bit is logical 0. Inject 0.7 A into
the relay and confirm that Relay Word bit 32IE asserts to logical 1. Type
TAR 50GC 10
and verify that Relay Word bit 50GC is logical 0. Stop
the injection and use the
SER
command to confirm the assertion of Relay
Word bit 32IF in approximately 1.5 cycles after the assertion of Relay
Word bit 32IE. Repeat the test injecting first in phase IBW3 and then in
phase ICW3.
Differential
The SEL-387E Relay has several components to its differential element. Figure 10.7 gives a
representation of the differential characteristic and the plot of each test. Each test only uses
Winding 1 and 2 inputs. Any combination of two winding inputs may be used for the test. The
differential elements for each winding must be enabled for each winding under test with the
E87W1, E87W2, and E87W3 settings. Set each setting equal to “Y” to enable the corresponding
differential element.
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