SEL-2126
Fiber-Optic Transfer Switch
Quickly Switch Fiber-Optic Communications
Reroute primary or secondary fiber-optic protection
communications in main-bus/transfer-bus applications.
Features and Benefits
Minimize Tripping Time
The SEL-2126 has a data delay of less than 10 μs. This is 400 to 1,000
times faster than traditional digital devices.
Install Flexible Relay Communications
Reroute communications from up to six pairs of line protection
relays to either or both of two bus-tie relays.
Improve Protection Scheme Availability
Independently or simultaneously allow current-differential protection and communications-assisted pilot tripping schemes to remain
in service during circuit breaker or substation maintenance.
Reduce Installation Costs With the IEEE C37.94
Interface Standard
Eliminate the need for expensive interface converters to link multiplexed synchronous communications to asynchronous devices.
Reroute Multiple Communications Protocols With
One Transfer Switch
Quickly and cleanly reroute any communications protocol carried
on the IEEE C37.94 fiber-optic interface standard without moving
fiber connectors and without changing communications equipment
programming.
Making Electric Power Safer, More Reliable, and More Economical ®
SEL-2126 Fiber-Optic Transfer Switch
Automate Protection Communications
• Transfer communication to two bus-tie relays simultaneously for
main-bus/transfer-bus schemes, station-bypass operations, threeterminal line applications, primary and backup communications
links, and local or remote relay testing.
• Choose between the default instantaneous switching time
(100 ms) and the delayed switching time (5 s). The delayed
switching time is jumper-selectable for applications where
switching requires more time to account for selector-switch
operation or mechanical transients.
• Preserve line protection communications during breaker or
station-bypass maintenance operations instead of disabling
communications-assisted tripping schemes (e.g., POTT, DCB, 87L).
• Use the 16 contact inputs to control fiber-port routing, and use
the two output contacts to report the system status.
• Automatically change group protection settings on the bus-tie
breaker relay to match the bypassed-relay protection settings,
or use an SEL-SSE, an SEL-SSP, or any other selector switch.
Main-Bus/Transfer-Bus Scheme Application
Normal Operation
Bypassed Operation
Tie-Circuit Breaker CB1
Protects Line B
Via Main Bus
Transfer Bus
Transfer Bus
SEL-2126
SEL-2126
CB3 Bypassed
Normal
SEL-2894
21
CB1
SEL-2894
21
Line B Receives
Power From
Transfer Bus
CB1
87L
87L
Main Bus
Main Bus
CB3
Line B
Line A
To Remote
Terminals
21
Multiplexer
87L
Local Circuit
Breaker CB3
Feeds Via Main Bus
CB2
87L
CB3
To Remote
Terminals
Line B
87L
Line A
CB2
SEL-2894
SEL-2894
Multiplexer
21
87L
Local Circuit
Breaker CB3
Feeds Via Main Bus
Operation
Operation
Current-differential (87L) andNormal
communications-assisted
protection (21) rerouted to bus-tie relayBypassed
during circuit
breaker or station maintenance.
Current-differential (87L) and communicationsassisted protection (21) rerouted to bus-tie relay
during circuit breaker or station maintenance.
General Specifications
Fiber-Optic Channels
Multimode, 50 or 62.5 mm cable, ST® connectors
Power Supply Ratings
20—250 Vdc
95—240 Vac, 60 Hz, <15 VA
Compatible with the IEEE C37.94 interface standard
Standard Control Input Voltage Options
24, 48, 110, 125, 220, or 250 Vdc
Operating Temperature
—40° to +85°C (—40° to +185°F)
Pullman, Washington USA
Tel: +1.509.332.1890 • Fax: +1.509.332.7990 • www.selinc.com • info@selinc.com
© 2005—2012 by Schweitzer Engineering Laboratories, Inc. PF00118 • 20120322