Siemens 6MD85, Manual

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Supervision of the Communication
The communication is continuously monitored by the devices.
If a number of defective data telegrams, or no data telegrams at all, are received, this is regarded as a failure
in the communication as soon as a failure time of 100 ms (default setting can be changed) is exceeded. A list
of the measured values is shown in a window in DIGSI 5 (defective telegrams per minute/hour; transmitted
and received telegrams per minute/hour, percentage fault rate per minute/hour). A corresponding failure indi-
cation is always available. If no alternative communication route exists (as in the ring topology), the protec-
tion function operating with the protection interface is not operating and the remote signals are not updated
on the receiver side.
If the communication is interrupted for longer than an adjustable time Data-connection failure, this is
regarded as a communication failure. A corresponding failure indication is always available.
Time Synchronization via the Protection Interface
All devices of a topology can be time-synchronized with one another. Synchronization is carried out with milli-
second accuracy. The synchronization works independently of the protection function and is exclusively for
simultaneous time keeping in the devices of a protection topology.
The device you set in the parameter
Address of device 1
is the device with index 1. This device functions
as the timing master in a protection topology. If the timing master is logged off and switched off, the device
with the next highest device index takes on the function of the timing master. The timing master synchronizes
the clocks of the other devices of this topology via the protection interfaces. The time of the timing master is
typically synchronized via a substation automation protocol (for example, Ethernet or SNTP) or via IRIG-B. For
this, these time sources must be set as the 1st time source and optionally as the 2nd time source in the timing
master. If available, the system switches over to the 2nd source upon outage of the 1st source in the timing
master. This time is communicated with millisecond accuracy to the other devices of the topology.
Set the protection interface as the 1st time source in the other devices of the topology. In this way, all events
in the devices of the protection topology are recorded with the same time and are time-synchronized even
across different switchgears. This simplifies fault analysis and the fault records are recorded with the same
time in all devices.
[dwtimesy-130212-01.tif, 1, en_US]
Figure 3-53 Time Synchronization in a Protection Topology
Figure 3-53 shows how device 1 with index 1 is synchronized with the devices 2, 3, and 4 via the protection
interface. Device 1 is synchronized externally from 2 sources (IRIG-B and SNTP via Ethernet).
System Functions
3.5 Protection Communication
SIPROTEC 5, High-Voltage Bay Controller, Manual 107
C53000-G5040-C015-9, Edition 11.2017