P.11.21
Date Code 20151029 Protection Manual SEL-411L Relay
Testing and Troubleshooting
Checking Relay Operation
In-Line Transformers
or Charging Current
Compensation
For applications that do not include in-line transformers or charging current
compensation, use the 87L Multiterminal Test procedure to check the
operation of the 87L element.
87L Multiterminal Test
The multiterminal test verifies the operation of all relays in the 87L zone and
their associated communications channels as a complete system as would be
done during acceptance or commissioning tests. This test is useful to verify
the speed and the security of the function and to verify charging current
compensation and in-line transformer operation. COMTRADE playback can
also be carried out using the multiterminal test. This procedure is applicable
for any number of terminals. The test connections are shown in Figure 11.3
(refer to Test Precautions).
87LP
1. Use the TEST 87L command to enter Test Mode.
2. Ensure that relay outputs are supervised or isolated. See Test
Precautions for details.
3. When prompted, select a characteristic test and multiterminal
mode. Choose the A element and normal or secure depending
on the particular settings to be tested.
Pickup Check
4. Begin the test with no current injected at any terminal.
5. Increase the A-phase current into the local terminal until the
A-phase element operates.
6. Confirm that the pickup value is:
Equation 11.1
7. Confirm that each of the remote relays also operates.
8. If there are two breakers at the local terminal, repeat
Step 4–Step 7 using the second current input of the local relay.
Radius Check
9. Inject an A-phase current with a magnitude equal to 0.2 pu
(Step 6) into the local terminal.
10. Inject an A-phase current with a magnitude of 1 pu into a
remote terminal, and adjust the phase angle at this terminal to
be 180 degrees out-of-phase with the local terminal current.
11. Confirm that the A-phase element is picked up.
12. Increase the local A-phase current until the element drops out.
13. Confirm that the dropout value is
Equation 11.2
I
DROPOUT
Tap
1
87LPR S
--------------------------=
To Next Page
Loading...
