10-28
Testing and Troubleshooting
Date Code 20020129
SEL-387E Instruction Manual
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: Connect the two current test sources as shown in Figure 10.6. Turn on the
current test source for A-phase of Winding 1 (IAW1) at the value
calculated above
and set the phase angle to zero degrees
. Turn on the
current test source for A-phase of Winding 2 (IAW2) at the calculated
starting current
and set the phase angle at 180
degrees
. Slowly decrease
the magnitude of current IAW2 until the 87R element asserts. 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 combination if desired.
Method: Repeat Steps 1 through 6 for each phase. Remember to view the
appropriate TARGET and apply current to the appropriate winding. The
computer terminal will display the LED labels from left to right when the
TAR F
command is issued.
Second-Harmonic Blocking
Note:
This test requires a current source capable of generating second-harmonic current. This
example tests the second-harmonic blocking function.
Step 1.
Purpose: Verify the second-harmonic restraint percentage.
Method: Execute
the
SHOWSET
command via the relay front panel or serial port
and verify the percentage of fundamental current that the magnitude of
second-harmonic current must exceed for differential restraint. Enter
SHO
PCT2<ENTER>
.
Step 2.
Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute
the
TARGET
command (i.e.,
TAR F 87R<ENTER>
). The
SEL-387E Relay now displays the state of several differential elements in
the second row of the front-panel LEDs. The 87R bit is the right-most
LED.
Step 3.
Purpose: Connect two current test sources to one phase of one winding input.
Method: Connect a current source to the IAW1 input. Connect a second current
source in parallel with the first source to the IAW1 input as shown in
Figure 10.8.
Step 4.
Purpose: Apply fundamental current to pick up the 87R element.
Method: Turn on the first current test source connected to the Winding 1 input
(IAW1) equal to the TAP1 setting multiplied by the connection constant A
shown in Table 10.3. The 87R LED will illuminate once current is applied
to the relay.
Содержание SEL-387E
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