Functions
2.2 Protection Data Interfaces and Protection Data Topology
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
87
You can determine a limit value
PROT1 max ERROR
for the permissible rate of faulty protection data telegrams
under address
4513
. This parameter can only be set in DIGSI at
Display Additional Settings
. The preset
value 1 % means that maximum one faulty telegram per 100 telegrams is permissible.
Protection data interface 2
If protection data interface 2 exists and is used, the same options as for protection data interface 1 apply. The
corresponding parameters are set at addresses
4601
STATE PROT I 2
(
ON
or
OFF
),
4602
CONNEC. 2 OVER
,
4605
PROT 2 T-DELAY
and
4606
PROT 2 UNSYM.
, the last two parameters can only be changed with DIGSI
under
Additional Settings
. If GPS synchronisation is available, the parameter is used at address
4611
PI2
SYNCMODE
. The maximum permissible rate of faulty protection data telegrams
PROT2 max ERROR
(address
4613
) and the reaction to impermissible transmission time difference
PI2 BLOCK UNSYM
(address
4615
)
(blocking the differential protection
YES
or
NO
) can be changed under
Additional Settings
.
GPS synchronisation (optional)
For the protection data interface, the synchronisation via GPS can be switched
ON
or
OFF
at address
4801
GPS-SYNC.
.
GPS synchronisation means the use of a 1-pulse-per-second signal (1 PPS). This signal is generated by an
external GPS receiver. The 1 PPS signal is connected to port A of the device (see Chapter 3, Table 3-12). The
1 PPS signal has the property that the leading edge presents a maximum deviation of 10
μ
s (compared
between 2 GPS receivers and under all GPS signal conditions). This feature does not depend on the location.
If the deviation of max. 10
μ
s is no longer ensured due to bad GPS receiving conditions, the 1 PPS signal must
be switched off by the GPS receiver.
In addition, these GPS receivers can provide further time signals, e.g. DCF77 or IRIG-B. These time signals
can be connected to port A as well. However, they are not suitable for a µs-accurate synchronisation of the
protection data interfaces and, consequently, of the differential protection. The edge accuracy of these time
signals is often insufficient.
At address
4803
TD GPS FAILD
you can specify the time after which the indication
„GPS loss“
(no. 3247)
is output.
Other parameters concerning the GPS synchronisation can be set individually for each protection data interface
(see above).