17
Date Code 20210405
Instruction Manual
SEL-FT50/SEL-FR12 Fault Transmitter and Receiver System
Network Deployment Overview
Research
The first step in the deployment process is to identify possible installation sites
for both the SEL-FR12 and SEL-FT50 devices, and then determine if a reliable
link can be established.
Short-Range Network
A short-range network will have the SEL-FT50 devices deployed within a short
distance of the SEL-FR12. A deployment is considered to be a short-range net-
work when the installed SEL-FT50 devices are visible from the SEL-FR12
antenna and there are no obstructions between the two devices.
Short-range networks do not require extensive system planning, but a simple link
budget estimation should still be performed to determine if the link margin is
acceptable (see
Appendix C: Link Budget Analysis on page 48
for details). Select
an SEL-FR12 antenna and feeder cable from the list shown in
Table 2
and
Table 3
and include the gain and loss information for these components in the
link budget analysis.
When the distance between the SEL-FR12 and the SEL-FT50 devices is short,
you can leave the device in low-gain mode. See
Setting SEL-FR12 Receiver Gain
on page 25
for instructions on when to use low gain vs. high gain. Low-gain
mode will limit the range of the SEL-FR12 but will reduce RF interference from
other devices.
SEL-RP50 Fault Repeaters can also be used on short range networks without
extensive planning, provided they are properly configured and installed as
described in Appanedix D.
Perform an Area Study
Most SEL-FT50/SEL-FR12 links require that you are able to see the SEL-FT50
from the SEL-FR12 antenna. If you cannot see the SEL-FT50 from the
SEL-FR12 antenna, perform an area study to determine if the link will work
properly. Perform an area study starting at the proposed SEL-FR12 site to deter-
mine if the site provides effective coverage. The area study determines the
expected receive power levels in the area around the SEL-FR12 site. The area
study combines the RF characteristics of the system (e.g., system TX power,
cabling losses, antenna gain, etc.), local geography, and ground cover to deter-
mine expected received power levels in the area around the SEL-FR12 sites.
Effective links require 15 dB of fade margin (how much the received power level
exceeds the received sensitivity). If the area study says that the link has less than
15 dB of margin, you should try raising the receiver antenna higher above
ground, using a receiver antenna with higher gain, or using a different receiver
site entirely.
In situations where obstacles such as trees, terrain, or buildings are blocking line-
of-sight from one or more SEL-FT50s, consider installing one or more
SEL-RP50 Fault Repeaters per SEL-FT50 on the same feeder as the obscured
SEL-FT50s. The repeaters will generally be installed in sets of three. For longer
obstruction zones, multiple repeater sites can be used (up to five). The suitability
of each segment (between the SEL-FT50 site and the SEL-RP50 site, between
successive SEL-RP50 sites, or between the SEL-RP50 site and the SEL-FR12)
can be determined by using the simple the Short-Range Network method, above.
Refer to
Appendix D: SEL-RP50 Fault Repeater Detailed Implementation on
page 54
when considering the use of SEL-FT50s.
NOTE:
Only one repeater may be
used with SEL-FT50s manufactured
prior to May 2021.
NOTE:
SEL-RP50s are not available
in all markets. See
Table 13
.
