Sel 411L - Page 748

P.11.34
SEL-411L Relay Protection Manual Date Code 20151029
Testing and Troubleshooting
Checking Relay Operation
f. Enter the 3, 2, and Q characters in like manner.
g. Highlight
ACCEPT and press ENT.
The relay displays the screen containing the F32Q and
R32Q elements.
Step 5. Calculate impedance thresholds.
a. For this test, apply an A-phase voltage of V
A
= 3V
2
=
18.0 180 V secondary.
b. Use Equation 11.18 to find the current that is equal to
the reverse impedance threshold Z2R:
Step 6. Use Equation 11.16 to find the current that is equal to the
forward impedance threshold Z2F:
Step 7. Use Equation 11.17 to determine the applied current angle
( I
TEST
):
Step 8. Apply a test current to confirm operation of R32Q and F32Q.
a. Connect a single current test source.
b. Apply an A-phase voltage of V
A
= 18.0 180 V
secondary.
c. Set the current source for I
A
= 0.0  96 A.
d. Slowly increase the magnitude of I
A
to apply the source
test current.
e. Observe the
RELAY ELEMENT LCD screen.
Relay Word bit R32Q asserts when |I
A
| = 0.4 A,
indicating that the relay negative-sequence current is
greater than the 50RP pickup threshold.
R32Q deasserts when |I
A
| = 4.5 A, indicating that the
relay negative-sequence calculation Z2c is now less
than the Z2 reverse threshold Z2R.
f. Continue to increase the current source while you
observe the
RELAY ELEMENT LCD screen.
Relay Word bit F32Q asserts when |I
A
| = 4.62 A,
indicating that the relay negative-sequence calculation
Z2c is less than the Z2 forward threshold Z2F.
Distance Elements
Apply voltages and currents to the relay analog inputs that simulate fault and
load conditions to test distance elements. The relay supervises distance
elements so that these elements operate under the appropriate conditions. Be
sure to satisfy all the element supervisory conditions before testing a relay
element. For supervisory conditions for a particular element, see Mho
Ground-Distance Elements on page P.3.178.
I
TEST
3I
2
3V
2
Z2R
-------------
18.0 180V
4.00
---------------------------------- 4.50 A====
I
TEST
3I
2
3V
2
Z2RF
---------------
18.0 180V
3.90
---------------------------------- 4.62 A====
I
TEST
 3I
2
3V
2
 Z1ANG 180 84 96=–=–==