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Protection data interface 1
At address 4501 STATE PROT I 1 protection data interface 1 can be switched ON or OFF. If it is switched
OFF, this corresponds to a transmission failure. In case of a previously existing 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. direct communication by fibre-optic cable with 512 kbit/s;
Com conv 64 kBit/s , i.e. via communication converters with 64 kbit/s (G703.1 or X.21);
Com conv 128 kBit/s, i.e. via communication converters with 128 kbit/s (X.21, copper cable);
Com conv 512 kBit/s, i.e. via communication converter 512 KBit/s (X.21) or communication converter for
2 MBit/s (G703-E1/T1);
IEEE C37.94, i.e. communication network connection with 1, 2, 4, or 8 slots.
The setting options depend on the parameterization of the functional scope and on the device variant. The data
must be identical at both ends of a communication route.
The setting depends on the properties of the communication medium. Generally, the response time of the dif-
ferential protection system is shorter the higher the transmission rate.
The devices measure and monitor the transmission times. Deviations are corrected as long as they are within
the permissible range.
The maximum permissible transmission time (address 4505 PROT 1 T-DELAY) is preset to a default value
that does not exceed the usual delay of communication networks. This parameter can only be set in DIGSI at
Display Additional Settings. If it is exceeded during operation, for example, because of switchover to a dif-
ferent transmission route, the message „PI1 TD alarm" (No. 3239) will be issued. The protection data in-
terface and the differential protection continue being in operation! Increased transmission times only have an
impact on the tripping time of the differential protection and therefore on the fault clearance time.
The maximum transmission time difference (outgoing signal vs. return signal) can be changed in address
4506 PROT 1 UNSYM.. This parameter can only be set in DIGSI at Display Additional Settings. The devices
assume symmetrical transfer times after establishing or re-establishing a connection. The maximum runtime
difference is considered as the maximum fault of synchronisation when calculating the restraint current.
If transmission time jumps exceeding the parameterized value of the maximum transmission time difference
(address 4506) occur in the communication networks, a proper function of the differential protection for high-
current faults outside the zone to be protected is not guaranteed. The device is able to record transmission
time jumps. At address 4515 PI1 BLOCK UNSYM (default YES), you can define whether the protection data
interface connection for the differential protection shall be blocked in this case. The protection data interface
can be unblocked by means of the message 3256 „PI1 unsym." or via the binary input 3252 „>SYNC PI1
RESET". The message 3256 is pre-allocated in DIGSI in the control menu. The unblocking may only be effect-
ed if the transmission times are symmetrical.
The following table provides setting hints for the parameters 4506 and 4515 when using different communica-
tion media or communication converters:
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
2.2 Protection Data Interfaces and Protection Data Topology
Functions
85
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