Sel 411L - Page 737

P.11.23
Date Code 20151029 Protection Manual SEL-411L Relay
Testing and Troubleshooting
Checking Relay Operation
7. Confirm that the pickup value is
Equation 11.4
8. Confirm that each of the remote relays also operates.
9. If there are two breakers at the local terminal, repeat
Step 5–Step 8 using the second current input of the local relay.
Radius Check
10. Inject a balanced three-phase current with an ACB rotation
with a magnitude equal to the minimum pickup (Step 7) into
the local terminal.
11. Inject a balanced three-phase current with an ACB rotation and
a magnitude equal to the minimum pickup (Step 7) into a
remote terminal. Adjust the phase angle at this terminal to be
180 degrees out-of-phase with the local terminal current.
12. Confirm that the Q element is picked up.
13. Increase the local current until the element drops out.
14. Confirm that the dropout value is
Equation 11.5
15. If there are two breakers at the remote terminal, repeat steps
Step 10–Step 14 using the second current input of the remote
relay.
Blocking Angle Check
16. Inject a balanced three-phase current with an ACB rotation and
a magnitude equal to the minimum pickup (Step 7) at the local
terminal.
17. Inject a balanced three-phase current with an ACB rotation and
a magnitude equal to the minimum pickup (Step 7) at a remote
terminal. Adjust the phase angle at this terminal to be
180 degrees out-of-phase with the local terminal.
18. Confirm that the value of k and alpha is 1.0  180 at both
relays and for all three phases and no relays have operated.
19. Rotate the angle of the local current counterclockwise until the
Q element picks up. Record this value as 1.
20. Rotate the angle of the local current clockwise until the element
drops out and picks up again. Record this value as 2.
21. Confirm that
Equation 11.6
22. For three- and four-terminal applications repeat Step 5–Step 21
using other relays as the remote terminal.
23. Repeat Step 1–Step 21 using other relays as the local terminal.
24. Use the TEST 87L command to exit Test Mode.
I
PICKUP
Tap 87LQP S=
I
DROPOUT
Tap
1
87LQR S
---------------------------=
360 1 2–+ 87LQA S=