Sel 421 - Figure 6.7 Sample Targets Display on a Serial Terminal; Table 6.6 Phase Instantaneous Overcurrent Pickup

U.6.14
SEL-421 Relay User’s Guide Date Code 20090715
Testing and Troubleshooting
Test Methods
View Relay Elements With a Serial Terminal
The procedure in the following steps shows you how to view a change in state
for the 50P1 Phase Instantaneous Overcurrent element from a
communications port. Use the factory defaults for the pickup level (see
Table 6.6). For more information on the 50P elements, see Instantaneous Line
Overcurrent Elements on page R.1.64.
For this procedure, you must have a serial terminal or computer with terminal
emulation software and a variable current source for relay testing.
This example assumes that you have successfully established communication
with the relay (see Making an EIA-232 Serial Port Connection on page U.4.5).
In addition, you must be familiar with relay access levels and passwords (see
Changing the Default Passwords on page U.4.6 to change the default access
level passwords and enter higher relay access levels).
Step 1. Type ACC <Enter> at a communications terminal.
Step 2. Type the Access Level 1 password and press <Enter>.
You will see the Access Level 1 => prompt.
Step 3. Connect a test source to the relay.
a. Set the current output of a test source to zero output
level.
b. Connect a single-phase current output of the test source
to the IAW analog input (see Figure 6.5 and Section 2:
Installation).
Step 4. Type TAR 50P1 <Enter> to view the initial element status.
The relay returns a target terminal screen similar to Figure 6.7.
=>TAR 50P1 <Enter>
50P1 50P2 50P3 50P4 67P1 67P2 67P3 67P4
0 0 0 0 0 0 0 0
=>
Figure 6.7 Sample Targets Display on a Serial Terminal
Step 5. View the element status change.
a. Type TAR 50P1 1000 <Enter> (this command causes
the relay to repeat the TAR 50P1 command 1000
times).
b. Increase the current source to produce a current
magnitude greater than 10.00 A secondary in the relay.
You will see the 50P1 element status change to 1 when
the input current exceeds the 50P1P setting threshold.
c. Type <Ctrl+X> to stop the relay from presenting the
target display before completion of the 1000 target
repeats.
Table 6.6 Phase Instantaneous Overcurrent Pickup
Setting Description Default (5A)
50P1P Level 1 Pickup (OFF, 0.25–100 amps secondary) 10.00
Courtesy of NationalSwitchgear.com