Sntp Server Requirements; Sample Specification Of Communication Requirements For The Protection And Control Terminals In Digital Telecommunication Networks - ABB Relion REC670 Applications Manual

Section 22
Requirements
The transient responses for three different standard transient response classes, T1, T2 and T3
are specified in chapter 6.503 of the standard. CVTs according to all classes can be used.
The protection IED has effective filters for these transients, which gives secure and correct
operation with CVTs.
22.3

SNTP server requirements

The SNTP server to be used is connected to the local network, that is not more than 4-5
switches or routers away from the IED. The SNTP server is dedicated for its task, or at least
equipped with a real-time operating system, that is not a PC with SNTP server software. The
SNTP server should be stable, that is, either synchronized from a stable source like GPS, or
local without synchronization. Using a local SNTP server without synchronization as primary or
secondary server in a redundant configuration is not recommended.
22.4 Sample specification of communication requirements
for the protection and control terminals in digital
telecommunication networks
The communication requirements are based on echo timing.
Bit Error Rate (BER) according to ITU-T G.821, G.826 and G.828
•
<10
Bit Error Rate (BER) for high availability of the differential protection
•
<10
•
<10
During disturbed conditions, the trip security function in can cope with high bit error rates up
-5
to 10 or even up to 10
from the differential protection communication supervision, or blocked when COMFAIL is
issued after receive error >100ms. (Default).
Synchronization in SDH systems with G.703 E1 or IEEE C37.94
The G.703 E1, 2 Mbit shall be set according to ITU-T G.803, G.810-13
• One master clock for the actual network
• The actual port Synchronized to 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
• Format.G 704 frame, structured etc.Format.
• No CRC-check
Synchronization in PDH systems connected to SDH systems
464
-6
according to the standard for data and voice transfer
-8 -9
-10 during normal operation
-6
during disturbed operation
-4
. The trip security can be configured to be independent of COMFAIL
1MRK 511 358-UEN A
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GUID-0A9F36AF-3802-42FE-8970-4662798C19D1 v1
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