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SEL-FT50/SEL-FR12 Fault Transmitter and Receiver System
Instruction Manual
Date Code 20210405
Appendix D: SEL-RP50 Fault Repeater Detailed Implementation
➤
Trio 2 uses two SEL-RP50 sites to reach the SEL-FR12 because of a
forested area
➤
Trio 3 uses one SEL-RP50 site to reach the SEL-FR12 because of a
forested area
➤
Trio 4 uses one SEL-RP50 site to reach the SEL-FR12 because of a
mountain
The SEL-RP50 harvests energy from line current, just like the SEL-FT50.
➤
In low-load or dead-line conditions (below 5 A) there is insufficient
energy available to operate the SEL-RP50. This is called the Off
State.
➤
In moderate load conditions, where line currents are between 5 A and
approximately 40 A, the SEL-RP50 is operating in a reduced energy
mode, called the Sleep State.
➤
In regular load states, above approximately 40 A, the SEL-RP50 is
fully functional, called the Awake State.
➤
During high load current or fault current conditions, energy harvest-
ing still occurs.
➤
From the Off state and the Sleep state, a power system fault will
wake up the SEL-RP50 almost instantly, and it will be listening for a
fault message from the SEL-FT50 (or another SEL-RP50).
➤
If the SEL-RP50 receives a fault message (from a device with match-
ing UNIT ID and NET ID) it will prepare to retransmit the message,
and then transmit after a brief delay. The delay is a function of the
Repeater ID setting, and avoids wireless signal collisions that would
prevent the message from getting through the system to the
SEL-FR12.
➤
When the fault current ends the SEL-RP50 will return (or stay) in an
operating state that corresponds to the line current.
➤
If the SEL-RP50 is not installed on the same electrical phase as the
SEL-FT50 with shared unit ID, it will not experience the same load
and fault current. If the SEL-RP50 is in the Off State or Sleep State, it
will not be able to wake up to hear receive any fault messages. This is
why it is important to install the SEL-RP50s on the same phase as the
SEL-FT50 (with matching Unit ID).
Figure 35
Energy Harvesting and SEL-RP50 Power States
