SEL-451 Data Sheet
Schweitzer Engineering Laboratories, Inc.
18
➤
Restrict breaker tripping in excessive duty
situations without additional relays.
➤
Construct a compensated overvoltage element for
open line overvoltage protection.
➤
Hold momentary change-of-state conditions for
SCADA polling.
➤
Provide a combination of frequency or rate-of-
change-of-frequency functions.
Relay-to-Relay Digital
Communications (M
IRRORED
B
ITS
)
The SEL patented M
IRRORED
B
ITS
technology provides
bidirectional relay-to-relay digital communication
(
). In the SEL-451, M
IRRORED
B
ITS
can oper-
ate simultaneously on any two serial ports for three-ter-
minal power system operation.
This bidirectional digital communication creates addi-
tional outputs (transmitted M
IRRORED
B
ITS
) and
additional inputs (received M
IRRORED
B
ITS
) for each
serial port operating in the M
IRRORED
B
ITS
communica-
tions mode. Communicated information can included
digital, analog, and virtual terminal data. Virtual terminal
allows operator access to remote bays through the local
bay. These M
IRRORED
B
ITS
can be used to transfer informa-
tion between line terminals to enhance coordination and
achieve faster tripping. M
IRRORED
B
ITS
also help reduce total
pilot scheme operating time by eliminating the need to close
output contacts and debounce contact outputs. Use the dual-
port M
IRRORED
B
ITS
communications capabilities for high-
speed communications-assisted schemes applied to three-ter-
minal transmission lines.
Communication
The SEL-451 offers the following serial communication
features.
➤
Four independent EIA-232 serial ports.
➤
Full access to event history, relay status, and meter
information.
➤
Settings and group switching have three levels of
password protection.
➤
DNP3 Level 2 Outstation.
➤
Patented SEL Fast Message Interleaving of ASCII
and binary data for SCADA communications,
including access to SER, relay element targets,
event data and more.
➤
Communication of synchronized phasor
measurement data using either SEL Fast
Messaging for Synchrophasors or IEEE C37.118–
2005
Standard for Synchrophasors for Power
Systems
.
Figure 23
Motor-Driven Reclose Timer
3rd Reclose
(Synchronism Check)
2nd Reclose
(Hot Bus/Dead Line)
1st Reclose
(Hot Line/Dead Bus)
Reset
Lockout
Figure 24
Integral Communication Provides Secure Protection, Monitoring, and Control, as Well as Terminal Access to
Both Relays Through One Connection
Fiber-Optic Cable
TX
RX
TX
RX
SEL-2815
SEL-2815
Other
Bays
Other
Bays
Bus 1
Bus 2
1
2
Digital, Analog, and Virtual Terminal Data
SEL-451
SEL-451
