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3.44
SEL-400 Series Relays
Instruction Manual
Date Code 20171006
Basic Relay Operations
Examining Relay Elements
View Relay Elements in the Terminal
The procedure in the following steps shows you how to view a change in state for
the SEL-451 50P1 Phase-Instantaneous Overcurrent element from a communica-
tions port.
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 3.4
). In
addition, you must be familiar with relay access levels and passwords (see
Changing the Default Passwords in the Terminal on page 3.10
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.
Step 4. Type
TAR 50P1 <Enter>
to view the initial element status.
The relay returns a target terminal screen similar to that shown in
.
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). For more infor-
mation on the
TAR
command see
b. Increase the current source to produce a current magnitude
greater than 15.00 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.
View Relay Elements From the Front-Panel LCD
You can use the front-panel display and navigation pushbuttons to check Relay
Word bit elements. See
Section 4: Front-Panel Operations
for more information
on using the relay front panel.
Table 3.7
Phase Instantaneous Overcurrent Pickup
Setting
Description
Default
50P1P
Level 1 Pickup (OFF, 0.25–100 A secondary)
15.00
=>
TAR 50P1 <Enter>
50P1 50P2 50P3 50P4 67P1 67P2 67P3 67P4
0 0 0 0 0 0 0 0
=>
Figure 3.35
Sample Targets Display on a Serial Terminal
Summary of Contents for SEL-421-4
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