2.2 Protection Data Interfaces and Protection Data Topology
85
7SD5 Manual
C53000-G1176-C169-1
2.2.3
Differential Protection Topology
2.2.3.1
Setting Notes
Protection Data
Topology
First of all, define your protection data communication topology: number the devices
consecutively. This numbering is a serial device index that serves for your own over-
view. It starts for each distance differential protection system (i.e. for each protected
object) with 1. For the differential protection system the device with index 1 is always
the absolute-chronology master, i.e. the absolute time management of all devices
which belong together depends on the absolute time management of this device, if
synchronization is set to
Timing-Master
. As a result the time information of all devices
is comparable at all times. The device index serves for unique definition of the devices
within the differential protection system (i.e. for one protected object).
An ID number is also to be given to each single device (device-ID). The device–ID is
used by the communication system to identify each individual device. It must be
between 1 and 65534 and must be unique within the communication system. The ID
number identifies the devices in the communication system (like a device address)
since the exchange of information between several differential protection systems
(thus also for several protective relay) can be executed via the same communication
system.
Please make sure that the possible communication links and the existing interfaces
are in accordance with each other. If not all devices are equipped with
two
protection
data interfaces, those with only
one
protection data interface must be located at the
ends of the communication chain. A
ring topology
is only possible if
all
devices in a
differential protection system are equipped with two protection data interfaces.
If you work with different physical interfaces and communications links, please make
sure that every protection data interface corresponds to the projected communication
link.
For a protected object with two ends (e.g. a line) the addresses
4701
ID OF RELAY
1
and
4702
ID OF RELAY 2
are set, e.g. for device 1 the device-ID
16
and for device
2 the device-ID
17
(Figure 2-12). The indices of the devices and the device-IDs do not
have to match here, as mentioned above.
Figure 2-12
Differential protection topology for 2 ends with 2 devices — example
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