10-12
Testing and Troubleshooting
Date Code 20020129
SEL-387E Instruction Manual
Step 1.
Purpose: Determine the expected instantaneous overcurrent element pickup value.
Method: Execute the
SHOWSET
command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 50P11P<ENTER>
).
Step 2.
Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute
the
TARGET
command (i.e.,
TAR F 50P11<ENTER>
). The
SEL-387E Relay now displays the state of several Winding 1 overcurrent
elements on the bottom row of front-panel LEDs.
Step 3.
Purpose: Connect and apply a single-current test source until the appropriate LED
illuminates.
Method: Connect a single-current test source (i.e., Source 1) as shown in
Figure 10.6. Turn on the current test source for the winding under test,
and slowly increase the magnitude of current applied until the appropriate
element asserts (i.e., 50P11), causing the LED to illuminate (i.e., left-
most). Note the magnitude of the current applied. It should equal the
50P1P setting ±5% of the setting ±0.02 I
nom
(negative-sequence elements
are ±6% of the setting ±0.02 I
nom
).
Step 4.
Purpose: Repeat test for each instantaneous overcurrent element for each winding.
Method: Repeat steps 1 through 3 for each instantaneous overcurrent element listed
in Table 10.1 for each winding. 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.
Figure 10.6: Test Connections for Two Single-Current Test Sources
