U.1.4
SEL-421/SEL-421-1 Relay
User’s Guide
Date Code 20020501
Introduction and Specifications
Features
Digital Relay-to-Relay Communication.
Use M
IRRORED
B
ITS
communications to monitor internal element conditions between
relays within a substation and between substations using
communication channels (SEL fiber-optic transceivers, for example).
Ethernet Communications Capability.
Add the optional plug-in SEL-2701
Ethernet Processor to implement control and data gathering
capabilities via substation local-area-networks (LANs) and company
wide-area-networks (WANs). Employ UCA and FTP protocols for
system data acquisition and control.
Increased Security.
The SEL-421 Relay divides control and settings into
seven relay access levels; the relay has separate breaker, protection,
automation, and output access levels, among others. Set unique
passwords for each access level.
Computer Software.
Use the rules-based settings editor, the
AC
SEL
ERATOR
software, to develop settings off-line. View a graphical
human machine interface (HMI) for metering and control.
Settings Reduction.
Internal relay programming shows only the settings
for the functions and elements you have enabled.
Summary of Contents for SEL-421
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