TerminalNo
, but equal to the
TerminalNo
of the remote end LDCM. In the remote IED the
TerminalNo
and
RemoteTermNo
settings are reversed as follows:
• LDCM for slot 302: Set
TerminalNo
to 2 and
RemoteTermNo
to 1
• LDCM for slot 303: Set
TerminalNo
to 4 and
RemoteTermNo
to 3
The redundant channel is always configured in the lower position, for example
• Slot 302: Main channel
• Slot 303: Redundant channel
The same is applicable for slot 312-313 and slot 322-323.
DiffSync
: Here the method of time synchronization,
Echo
or
GPS
, for the line differential
function is selected.
Using
Echo
in this situation is safe only as long as there is no risk of varying
transmission asymmetry.
GPSSyncErr
: If GPS synchronization is lost, the synchronization of the line differential function
will continue during 16 s. based on the stability in the local IED clocks. Thereafter the setting
Block
will block the line differential function or the setting
Echo
will make it continue by using
the
Echo
synchronization method. It shall be noticed that using
Echo
in this situation is only
safe as long as there is no risk of varying transmission asymmetry.
CommSync
: This setting decides the
Master
or
Slave
relation in the communication system
and shall not be mistaken for the synchronization of line differential current samples. When
direct fibre is used, one LDCM is set as
Master
and the other one as
Slave
. When a modem and
multiplexer is used, the IED is always set as
Slave
, as the telecommunication system will
provide the clock master.
OptoPower
has two settings:
LowPower
and
HighPower
.
Short-range LDCM: Use
LowPower
for fibers 0 – 1 km and
HighPower
for fibers greater than 1
km.
Medium-range LDCM: Typical distance 80 km for both
LowPower
and
HighPower
.
Long-range LDCM: Typical distance 120 km for both
LowPower
and
HighPower
.
An optical budget calculation should be made for the actual case. For medium range LDCM and
long range LDCM the recommendation is to use the
LowPower
setting to minimize the power
consumption and keep the heat dissipation at minimum.
The
HighPower
setting adds 3 dBm extra optical power and can be used to increase the
margin at distances close to maximum.
Table 47: Optical budgets with C37.94 protocol
Type of LDCM
Short range (SR) Short range (SR) Medium range (MR) Long range (LR)
Type of fibre Multi-mode fiber
glass 50/125 μm
Multi-mode fiber
glass 62.5/125 μm
Single-mode fiber
glass 9/125 μm
Single-mode fiber
glass 9/125 μm
Modem type 1MRK0002122-AB 1MRK0002122-AB 1MRK002311-AA 1MRK002311-BA
Contact type ST ST FC/PC FC/PC
Table continues on next page
1MRK 511 358-UEN A Section 19
Remote communication
433
Application manual
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