10.31
Date Code 20050919
Instruction Manual
SEL-387-0, -5, -6 Relay
Testing and Troubleshooting
Acceptance Testing
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.
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.
The following test applies to a single-harmonic injection at a
time, i.e., only the second or the fourth harmonic, not both.
a. Set E87W1 = E87W2 = Y1, and HRSTR = Y.
b. Set the second current source for second-harmonic
current (120 Hz for NFREQ = 60 and 100 Hz for
NFREQ = 50).
c. Turn on the second current test source connected to the
Winding 1 input (
IAW1
).
d. Starting at zero current, slowly increase the magnitude
of applied current until the 87R element deasserts,
causing the 87R LED to extinguish completely. Note
the value of the applied current from the second test
source. The general equation to calculate the percentage
of harmonic content for a single slope is: (±5% ±0.10
A (5 A relay) or ±5% ±0.02 A (1 A relay)):
Equation 10.12
and
Equation 10.13
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.
I1F2
IOP1
IRT1
–
f
SLP
(
)
• •
[
]
PCT
100
-----------
•
=
% harmonic
I1F2
IOP1
-------------
100 percent
•
=
Содержание SEL-387-0
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