ABB Relion 670 Series Applications Manual page 516

Section 22
Requirements
22.2 Voltage transformer requirements
The performance of a protection function will depend on the quality of the measured input signal.
Transients caused by capacitive Coupled voltage transformers (CCVTs) can affect some
protection functions.
Magnetic or capacitive voltage transformers can be used.
The capacitive voltage transformers (CCVTs) should fulfill the requirements according to the IEC
61869-5 standard regarding ferro-resonance and transients. The ferro-resonance requirements of
the CCVTs are specified in chapter 6.502 of the standard.
The transient responses for three different standard transient response classes, T1, T2 and T3 are
specified in chapter 6.503 of the standard. CCVTs according to all classes can be used.
The protection IED has effective filters for these transients, which gives secure and correct
operation with CCVTs.
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 to
-5
10 or even up to 10
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
510
-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 from the
1MRK 511 358-UUS A
M11608-3 v5
GUID-588FCD12-C494-445E-8488-8287B34EFD9A v4
GUID-0A9F36AF-3802-42FE-8970-4662798C19D1 v1
Application manual