2.2 Protection Data Interfaces and Protection Data Topology
81
7SD5 Manual
C53000-G1176-C169-1
2.2.2
Protection Data Interfaces
2.2.2.1
Setting Notes
General
Information about
Interfaces
The protection data interfaces connect the devices with the communication media.
The communication is permanently monitored by the devices. Address
4509
T-DATA
DISTURB
defines after which delay time the user is informed about a faulty or missing
telegram. Address
4510
T-DATAFAIL
is used to set the time after which a transmis-
sion failure alarm is output. Address
4512
Td ResetRemote
determines how long
time remote information remains standing after a transmission fault has been cleared.
Protection Data
Interface 1
The protection data interface 1 can be turned
ON
or
OFF
in address
4501
STATE PROT
I 1
. If it is switched
OFF
, this corresponds to a transmission failure. In case of a ring
topology, the differential protection and all functions which require the transmission of
data, can continue their operation, but not in case of a chain topology.
In address
4502
CONNEC. 1 OVER
, set the transmission media that you want to
connect to protection data interface PI 1. The following selection is possible:
F.optic direct
, i.e. communication directly by fibre-optic cable with 512 kBit/s;
Com conv 64 kB
, i.e. via communication converters with 64 kBit/s (G703.1 or X.21or
S0);
Com conv 128 kB
, i.e. via communication converters with 128 kBit/s (X.21, copper
cable);
Com conv 512 kB
i.e. via communication converter 512 kbit/s (X.21).
The possibilities may vary for the different device versions. The data must be identical
at both ends of a communication route.
The setting depends on the features of the communication media. As a general rule,
it can be stated that the higher the transmission rate the shorter the tripping time of the
differential protection system.
The devices measure and monitor the transmission times. Deviations are corrected,
as long as they are within the permissible range. These permissible ranges are set
under addresses
4505
and
4506
and can normally be left at their default values.
The maximum permissible transmission time (address
4505
PROT 1 T-DELAY
) is
preset to a value that does not exceed the usual delay of communication networks.
This parameter can only be altered with DIGSI
®
under
Additional Settings
. If it is ex-
ceeded during operation (e.g. because of switchover to a different transmission route),
the message
„PI1 TD alarm“
(No. 3239) will be issued. Increased transmission
times only have an impact on the tripping time of the differential protection system.
The maximum
transmission time difference
(outgoing telegram vs. return telegram)
can be altered in address
4506
PROT 1 UNSYM.
. This parameter can only be altered
with DIGSI
®
under
Additional Settings
. With a direct fibre-optic connection, this value
can be set to
0
. For transmission via communication networks a higher value is
needed. The standard value is 100
µ
s (default setting). The permissible transmission
time difference has a direct influence on the sensitivity of the differential protection.
If GPS synchronization is used this value is relevant only in case the GPS signal is
missing. As soon as the GPS synchronization is restored, the transmission time differ-
ences are compensated again. As long as GPS synchronization is intact, transmission
time differences do
not
affect the sensitivity of the protection.
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