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U.5.18
SEL-421/SEL-421-1 Relay
User’s Guide
Date Code 20020501
Front-Panel Operations
Front-Panel Menus and Screens
Figure 5.20
BREAKER CONTROL Screens.
Local Control Bits
The relay provides 32 local control bits. These local bits replace substation
control handles to perform switching functions such as bus transfer switching.
The SEL-421 Relay saves the states of the local bits in nonvolatile memory
and restores the local bit states at relay power-up.
Any unused local control bits default to the clear (logical 0) state. Also, any
reconfigured local bit retains the existing bit state after you change the bit
setting. Deleting a local bit sets that bit to the clear (logical 0) state.
shows a control example using the LOCAL
CONTROL menus. The LCD shows a graphic representation of a substation
control handle. If the local bit is in the clear state, the graphic control handle
points to 0; if the local bit is in the set state, the switch points to 1. You can
program names or aliases for the local bit clear and set states; these appear
next to logical 0 and logical 1, respectively, in the lower portion of the sample
Bus Tie Interlock screens of
. Use the
{Up}
and
{Down}
pushbuttons to highlight the set (1) or clear (0) control actions. Highlighting
the set option (shown in
as “Closed (OK to TIE)”) and pressing
{ENT}
changes the local control bit and performs the required control action.
The graphical switch moves to 1 to indicate the new local bit status.
--BREAKER CONTROL--
--OUTPUT TESTING--
LOCAL CONTROL
Enable Bus Switching
North Bus MOD
South Bus MOD
Bus Tie Interlock
Alternate Settings 3
BREAKER 1
BREAKER 2
SELECT A BREAKER
BREAKER CONTROL
TRIP BREAKER 1
CLOSE BREAKER 1
BREAKER 1
CLOSED
BREAKER 1 STATUS
TRIP BREAKER 1
CLOSE BREAKER 1
BREAKER 1
OPEN
BREAKER 1 STATUS
PRESS TO ACTIVATE
PRESS TO ACTIVATE
Summary of Contents for SEL-421
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