Applications
2.2
F6 TELEPROTECTION
2.2.1
OVERVIEW
The PLC-TT module uses type F6 teleprotection, which is a single tone system that only sends one
tone at a time from one end of the protected line to the other. Different combinations of inputs use
priority tables to generate the correct tone and the correct output at the receiving end. This system has
two, four or eight inputs and outputs. Each input can be inverted or not, and if eight inputs are used,
two inputs can be AND’ed or OR’ed to form each of four command inputs. The transmitted command
is determined by two priority tables; one based on 2+2 mode and the other based on 3+1 mode. 2+2
mode means 2 uncoded signal transmissions and 2 coded signal transmissions. 3+1 mode means 3
uncoded signal transmissions and 1 coded signal transmissions. Uncoded signal transmissions are
single tone only and are typically used for blocking or permissive underreach or permissive overreach.
Coded signal transmissions have two alternating tone frequencies and are typically used for increased
security.
The input command is sent to the PLC transceiver. Depending on the mode and the command, the PLC
transceiver sends one frequency for the entire time or sends two alternating frequencies for a specified
time. The receiver must receive each tone for a specified period before declaring a trip reception. Once
the receiver has determined that a valid trip has been received, the RX trip command is sent to the
PLC-TT module where it is decoded into output contacts in accordance with a user setup similar to that
used for the inputs.
Table 2-1. Input Command Priority Table for “2+2” Mode
Input Command*
Frequency
(1 for uncoded, 2 for coded)
Receiver Output
No input
Pilot
None
No input
F1
Test
A F3
A
B F5
B
A&B F7
A&B
C F2,F4
C
D F2,F6
D
C&D F4,F6
C&D
A&D F6,F8
A&D
B&C F4,F8
B&C
A&C F2,F4
C
B&D F2,F6
D
A&B&C F4,F8
B&C
A&B&D F6,F8
A&D
A&C&D F4,F6
C&D
B&C&D F4,F6
C&D
A&B&C&D F4,F6
C&D
* A, B, C, and D correspond to Trip Inputs/Outputs 1, 2, 3 and 4 on the PLC-TT I/O adapter module.
RFL 9508D UCC
RFL Electronics Inc.
July 1, 2007
2-5
(973) 334-3100
