Schweitzer Engineering Laboratories SEL-421-4 - Page 133

4.5
Date Code 20171021 Instruction Manual SEL-421 Relay
Front-Panel Operations
Front-Panel Menus and Screens
NOTE: Global settings ESS (Enable
Source Selection) and NUMBK
(Number of Circuit Breakers) affect
how the SEL-421 determines the line
current and the voltage source for
protection functions (directional
elements, load encroachment, out-of-
step logic, distance element, and loss-
of-potential).
Combinations of relay Global settings ESS and NUMBK give you metering data
for Line, Circuit Breaker 1, and Circuit Breaker 2 when you view
RMS METER,
FUNDAMENTAL METER, and MAX/MIN metering screens. The relay shows the METER
SUBMENU
of Figure 4.3 so you can choose the line or circuit breaker data that you
want to display.
For example, if you have two sources feeding a transmission line through two cir-
cuit breakers and you set ESS := 3, NUMBK := 2, then the SEL-421 measures
BREAKER 1 currents, BREAKER 2 currents, and combined (Circuit Breakers 1 and
2) currents for
LINE. The relay displays the METER SUBMENU screen when you
make this settings configuration.
Other combinations of settings ESS and NUMBK do not require separate circuit
breaker metering screens; for these configurations, the relay does not present the
METER SUBMENU screen. See Section 5: Protection Functions and Global Settings
on page 6.3 for information on configuring global settings ESS, NUMBK,
LINEI, BK1I, and BK2I.
The relay presents the meter screens in the order shown in each column of
Figure 4.4 and Figure 4.5. Once you have selected the type of metering data to
display (
RMS METER, FUNDAMENTAL METER, DEMAND METER, ENERGY METER, MAX/
MIN
, or SYNCHRONISM CHECK), you can scroll through the particular display col-
umn by pressing the Down Arrow pushbutton. Return to a previously viewed
screen in each column by pressing the Up Arrow pushbutton. Press ESC to revert
the LCD screen to the
METER SUBMENU and METER MENU screens.
The metering screens show reset options for the
MAX/MIN, ENERGY METER, PEAK
DEMAND METER
, and DEMAND METER metering quantities at the end of each screen
column. Use the Left Arrow and Right Arrow pushbuttons to select a
NO or YES
response to the reset prompt, and then press ENT to reset the metering quantity.
Figure 4.3 METER SUBMENU
METER SUBMENU
LINE
BREAKER 1
BREAKER 2