Sel 421 - Page 217

U.4.79
Date Code 20090715 User’s Guide SEL-421 Relay
Basic Relay Operations
Readying the Relay for Field Application
If you see no error message, the new settings are loaded
in the relay.
To confirm that you have prepared an out-of synchronization/loss of HIRIG
mode alarm, disconnect the IRIG-B input. The relay alarm will activate.
Readying the Relay for Field Application
Before applying the SEL-421 in your power system, set the relay for your
particular field application. Be sure to modify the relay factory default settings
for your power system conditions to enable relay features to help you protect
and control your system.
This procedure is a guide to help you ready the relay for field application. If
you are unfamiliar with the steps in this procedure, see the many relay usage
examples presented in this section. This is a suggested procedure; modify the
procedure as necessary to conform to your standard company practices.
Step 1. Open the appropriate low-voltage breaker(s) and remove fuses
to verify removal of control power and ac signals from the
SEL-421.
Step 2. Isolate the relay TRIP control output.
Step 3. Perform point-to-point continuity checks on the circuits
associated with the SEL-421 to verify the accuracy and
correctness of the ac and dc connections.
Step 4. Apply power to the relay (see Connecting and Applying Power
on page U.4.3).
The green ENABLED LED on the front panel will illuminate.
Step 5. Use an SEL Cable C234A to connect a serial terminal to the
relay.
Step 6. Start the terminal (usually a PC with terminal emulation
software).
Step 7. Establish communication with the relay at Access Level 0.
Step 8. Proceed to Access Level 2 (see Changing the Default
Passwords on page U.4.6).
Step 9. Change the default passwords (see Changing the Default
Passwords on page U.4.6).
Step 10. Set the DATE and TIME (see Making Simple Settings Changes
on page U.4.13).
Step 11. Use test sources to verify relay ac connections (see Examining
Metering Quantities on page U.4.33).
Step 12. Verify control input connections (see Operating the Relay
Inputs and Outputs on page U.4.56 and Control Inputs on
page U.2.5).
Step 13. Verify control output connections (see Operating the Relay
Inputs and Outputs on page U.4.56 and Control Outputs on
page U.2.7).
Step 14. Perform protection element tests (see Checking Relay
Operation on page U.6.24).
Courtesy of NationalSwitchgear.com