Section 6 Appendix
6.1 Sample specification of communication requirements
GUID-5F3AF242-270C-4FA2-8DA3-7A3532609D7B v1
This chapter provides a sample specification of communication requirements for line differential
protection IEDs in telecommunication networks. The requirements are based on echo timing.
Bit error rate (BER) according to ITU-T G.821, G.826 and G.828
•
< 10
-6
according to the standard for data and voice transfer
Bit error rate (BER) with high availability of the line differential protection
IED
•
< 10
-8
to 10
-9
during normal operation
•
< 10
-6
during disturbed operation
During disturbed operation, the trip security function in the line differential protection IED
can cope with high bit error rates up to 10
-5
or even up to 10
-4
. Trip security can be
configured to be independent from COMFAIL of the line differential protection
communication supervision, or it can be blocked when COMFAIL is issued after receive
error > 100 ms (default).
Synchronization in SDH systems with G.703 E1 or IEEE C37.94
G.703 E1 (2 Mbit/s) is set according to ITU-T G.803, G.810-13.
• One master clock for the actual network
• Actual port synchronized from the SDH system clock at 2048 kbit
• Synchronization: bit synchronized, synchronized mapping
• Maximum clock deviation: < ±50 ppm nominal, < ±100 ppm operational
• Jitter and wander according to ITU-T G.823 and G.825
• Buffer memory: < 250 μs, < 100 μs asymmetric difference
• G.704 frame format: structured, unstructured, and so on
• No CRC check
Synchronization in PDH systems connected to SDH systems
• Independent synchronization, asynchronous mapping
• Actual SDH port set to allow transmission of the master clock from the PDH network (SDH
network in transparent mode)
• Maximum clock deviation: < ±50 ppm nominal, < ±100 ppm operational
• Jitter and wander according to ITU-T G.823 and G.825
• Buffer memory: <1 00 μs
• Format: transparent
• Maximum channel delay
• Loop time: < 40 ms continuous (2 x 20 ms)
Line differential protection IED with echo synchronization (no GPS clock)
• Both channels to have the same route with maximum asymmetry of 0.2–0.5 ms depending on
the set sensitivity of the line differential protection function
• Fixed asymmetry can be compensated for by setting the AsymDelay on the local HMI or via PST
Line differential protection IED with GPS synchronization (GPS clock)
• Independent of asymmetry
1MRK505382-UEN Rev. K Section 6
Appendix
Communication set-up, 670/650 series 93
Application Guide
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