- 1126 -
PLC setting samples
7.4.1 Tele-protection scheme using DISCAR and DEFCAR commands
The distance carrier command protection (DISCAR†) or the directional earth fault command
protection (DEFCAR†) can realize permissible transfer tripping (or blocking remote tripping).
Between IEDs at the local and remote terminals, the signals generated in the DISCAR and
DEFCAR functions can be transmitted using the sub-communication bits (COM1, COM3‡, and
COM4‡) of the transmission control function (DIF_COMM), when the user has PLC
connections in the DISCAR, DEFCAR, DIF_COMM functions at the both terminals. Note that
this tele-protection scheme is not programmed for the operation in the Normal (N=1) frame.
At both the terminals, the user has to make the transmitter and receiver tele-protection logic
using the PLC editor.
†Note: For more information about the tele-protection, see the DISCAR and DEFCAR
functions in
Chapter Relay application
.
‡Note: The COM3 and COM4 bits are laid out in Wide frame structure (N=3) when the
DIF_COMM function has setting [CH*_COM_WIDTH] = Wide.
§Note: Other transfer tripping can be achieved using the direct transfer trip (DTT)
function, but the DTT scheme makes tripping the CB unconditionally if a trip
command is generated in trip circuits (TRC) at any terminals. The user is
recommended to set On for the [INTCOM] in case that the scheme does not operate
properly.
(i) Transmitter tele-protection logic
The DISCAR and DEFCAR functions generate carrier commands for the tele-protection; their
commands can be sent for the remote terminal, when the user makes the transmitter logic
with the COMM_APPL function. Table 7.4-1 (and Figure 7.4-1) shows the sample PLC logic,
when the IED has VCT12B arranged for the 1CB system. Table 7.4-2 (Figure 7.4-2) shows the
other PLC logic, when the IED has a VCT11B arranged for the 1.5CB system. Sample PLC
logic for the sub-communication channel (COM1-1-S) is illustrated in Figure 7.4-5; the user is
required to make the similar PLC logics for the other sub-communication channels (i.e., COM1-
2-S, COM3-1-S, etc.) at the local and the remote terminals.
To Next Page
Loading...
