10.28
SEL-387-0, -5, -6 Relay
Instruction Manual
Date Code 20170601
Testing and Troubleshooting
Acceptance Testing
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-387 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:
a. Connect a current source to the
IAW1
input.
b. Connect a second current source in parallel with the
first source to the
IAW1
input as shown in
.
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
. The
87R
LED
will illuminate once current is applied to the relay.
Step 5. Purpose: Apply and ramp fifth-harmonic current to dropout the
87R element.
Method:
a. Turn on the second current source for fifth-harmonic
current (300 Hz for NFREQ = 60 and 250 Hz for
NFREQ = 50).
b. Starting at zero current, slowly increase the magnitude
of this second current source until the 87R element
deasserts, causing the 87R LED to completely
extinguish. Note the value of the applied current from
the second test source. The current from the fifth-
harmonic source should equal the PCT5 setting divided
by 100, multiplied by the magnitude of the fundamental
current source, ±5% and ±0.02 I
NOM
.
IAW1 (fifth harmonic) = PCT5/100 • IAW1
(fundamental), ±5% ±0.02 I
NOM
Harmonic Restraint (All But SEL-387-0 Relay)
Step 1. Purpose: Verify the second-harmonic restraint percentage.
Method:
a. Execute the
SHOW
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.
b. 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-387 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.
NOTE:
This test requires a current
source capable of generating second
and fourth-harmonic current. This
example tests the second-harmonic
restraint function. Test the fourth
harmonic in a similar way.
Summary of Contents for SEL-387-0
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