Schweitzer Engineering SEL-387-0, Instruction Manual

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10.24
SEL-387-0, -5, -6 Relay Instruction Manual Date Code 20170601
Testing and Troubleshooting
Acceptance Testing
The A and B connection compensation constants are
based on
Table 10.4 . Since the windings have the same
W n CTC setting, the A and B constants will be the same
for both windings. The constants must be used to
achieve the exact curve point on which we have based
the calculations. The TAP
n settings can be different for
the two windings.
Step 5. Purpose: Calculate the initial current for Winding 2 for this test.
Method: Calculate the Winding 2 initial current for the test
using the following formula:
Equation 10.7
This formula determines the current necessary for IOP = 0
given the
IAW1 calculated above.
Step 6. Purpose: Connect a single current test source to A-phase of
Winding 1 and a single current test source to A-phase of
Winding 2. Ramp down Winding 2 current until the appropriate
LED illuminates.
Method:
a. Connect the two current test sources as shown in
Figure 10.5 .
b. Turn on the current test source for A-phase of
Winding 1 ( IAW1 ) at the value calculated above, and set
the phase angle at zero degrees .
c. Turn on the current test source for A-phase of
Winding 2 ( IAW2 ) at the calculated initial current and
set the phase angle at 180 degrees .
d. Slowly decrease the magnitude of
IAW2
until the 87R1
element asserts.
e. Use 87R2 when injecting current into B-phase and
87R3 when testing C-phase. Note the magnitude of the
current applied. It should equal the value calculated in
step 4±5% ±0.02 I
NOM
.
Step 7. Purpose: Repeat the test for each phase for each winding if
desired.
Method:
a. Repeat Step 1 through Step 6 for each phase.
b. Remember to view the appropriate TARget and apply
currents to the appropriate windings. The computer
terminal will display the LED labels from left to right
when the
TAR F command is issued.
IRS1 must be greater than:
Equation 10.8
if SLP2 is not set to OFF.
!
CAUTION
The continuous rating of the current
inputs is 3 • I
NOM
. If any currents in
this test will exceed this rating, reduce
the TAPn values as needed, to prevent
possible damage to the input circuits.
IAW2 IAW1
TAP2
TAP1
---------------
B
A
----
 
 
• • =
100
SLP1
--------------
087P
•