57
Date Code 20210405
Instruction Manual
SEL-FT50/SEL-FR12 Fault Transmitter and Receiver System
Technical Support
Link Message repeating:
➤
When a feeder is powered up to a low load condition, the SEL-RP50
wireless repeaters are in a sleep state and do not continually operate.
In this state they periodically turn on the radio to listen for Link sig-
nals, and then go back to sleep to save energy. The system is
designed to eventually capture an incoming Link message and then
synchronize the wake up timer.
➤
Once synchronized, the SEL-RP50 will wake up regularly in time to
catch the incoming link message, and then retransmit the link mes-
sage to the next device. This synchronization can take up to 30 min-
utes per SEL-RP50.
➤
A system with the maximum of five SEL-RP50s on the same Unit ID
could take several hours for the SEL-FR12
LINK
LED to illuminate.
This delay is shorter if the SEL-RP50s nearest the feeder source
(substation).
➤
When the SEL-RP50 is in the Awake mode there is no synchroniza-
tion delay because the wireless receiver is on all of the time. If the
load current later drops below the level needed to remain in the
Awake state, the SEL-RP50 will remember the synchronization and
should be able to keep transmitting link messages without needing to
resynchronize.
➤
If the line current drops below the sleep state level, the SEL-RP50
shuts down, and when sleep level current later comes back, it must
resynchronize.
➤
If the system is fully synchronized but the SEL-FT50 loses current
for over one minute, it will stop transmitting Link messages. Any
SEL-RP50s in the sleep state will lose synchronization. When the
SEL-FT50 load current reappears and it resumes transmitting Link
messages, all SEL-RP50s that are in sleep mode will need to resyn-
chronize.
➤
During all of these resynchronization cases, the SEL-FT50/
SEL-FR12 system still responds to faults, if the devices are installed
on the proper phase, as shown in
Figure 35
.
Technical Support
We appreciate your interest in SEL products and services. If you have questions
or comments, please contact us at:
Schweitzer Engineering Laboratories, Inc.
2350 NE Hopkins Court
Pullman, WA, 99163-5603 U.S.A.
Tel: +1.509.338.3838
Fax: +1.509-332-7990
Internet: selinc.com/support
Email: [email protected]
