U.4.20
SEL-421/SEL-421-1 Relay User’s Guide Date Code 20020501
Basic Relay Operations
Making Simple Settings Changes
=>>SET G NFREQ<Enter>
Global
General Global Settings
Nominal System Frequency (50,60 Hz) NFREQ := 60 ?<Enter>
System Phase Rotation (ABC,ACB) PHROT := ABC ?<Enter>
Date Format (MDY,YMD,DMY) DATE_F := MDY ?YMD<Enter>
Fault Condition Equation (SELogic Equation)
FAULT := 50P1 OR 51S1 OR M2P OR Z2G OR M3P OR Z3G
? END<Enter>
•
•
•
Save settings (Y,N) ?Y<Enter>
Saving Settings, Please Wait...........
Settings Saved
=>>
Figure 4.13 Initial Global Settings.
Step 3. Accept default settings. For a 60 Hz system, simply press
<Enter> to accept the NFREQ existing value of 60 (Hz). The
relay presents the next setting, which is the PHROT (phase
rotation) setting. Type <Enter> to accept the ABC phase
rotation default.
Step 4. Set the date format. The SEL-421 Relay reports dates in three
formats: MDY, YMD, and DMY (where M = month, D = date,
and Y = year). For this procedure type YMD<Enter>. At each
setting in turn, the relay presents the settings prompt, name,
present value, and action prompt. Note that SEL
OGIC control
equation settings, such as FAULT in Figure 4.13, appear on
multiple lines.
If you make a mistake or want to go backward through the
settings, type the ^ character (on most computer keyboards,
this is a shifted numeral 6) and <Enter>. Refer to Table 4.6 on
page 4.19 for this and other navigational aids.
Step 5. End the settings session. Type END<Enter> at the FAULT
action prompt. (The FAULT SEL
OGIC control equation remains
unchanged.) The relay next scrolls a readback of all the Global
settings, eventually displaying the “Save settings (Y, N) ?”
prompt. (In Figure 4.13, a vertical ellipsis represents the relay
information during readback.) Examine the settings readback to
verify your new settings. Answer Y<Enter> to save your new
settings.
The TERSE Option
You can avoid viewing the entire class settings summary the relay displays
when you type END<Enter> midway through a settings class or instance. On
slow data speed links, waiting for the complete settings readback can clog
your automation control system or take too much of your time for a few
settings changes. Eliminate the settings readback by appending TERSE to the
SET command.
To Next Page
