ABB RELION 670 Series Applications Manual page 26

Table of contents
22.12.2 Setting guidelines...................................................................................................................... 713
22.13 Time synchronization.................................................................................................................... 713
22.13.1 Application.................................................................................................................................. 713
22.13.2 Setting guidelines......................................................................................................................714
22.13.2.1 System time.............................................................................................................................714
22.13.2.2 Synchronization...................................................................................................................... 714
22.13.2.3 Process bus IEC 61850-9-2LE synchronization................................................................. 715
Section 23 Requirements...................................................................................................717
23.1 Current transformer requirements.............................................................................................717
23.1.1 Current transformer classification.........................................................................................717
23.1.2 Conditions................................................................................................................................... 717
23.1.3 Fault current............................................................................................................................... 718
23.1.4 Secondary wire resistance and additional load...................................................................718
23.1.5 General current transformer requirements..........................................................................719
23.1.6 Rated equivalent secondary e.m.f. requirements............................................................... 719
23.1.6.1 Transformer differential protection...................................................................................719
23.1.6.2 Distance protection...............................................................................................................720
23.1.6.3 Breaker failure protection.....................................................................................................721
23.1.6.4 Restricted earth fault protection (low impedance differential)................................... 722
23.1.7 Current transformer requirements for CTs according to other standards...................724
23.1.7.1 Current transformers according to IEC 61869-2, class P, PR........................................ 724
23.1.7.2 Current transformers according to IEC 61869-2, class PX, PXR (and old IEC
60044-6, class TPS and old British Standard, class X)....................................................725
23.1.7.3 Current transformers according to ANSI/IEEE................................................................ 725
23.2 Voltage transformer requirements............................................................................................ 726
23.3 SNTP server requirements........................................................................................................... 726
23.4 Sample specification of communication requirements for the protection and
control terminals in digital telecommunication networks.................................................... 726
23.5 IEC 61850-9-2LE Merging unit requirements ...........................................................................727
Section 24 Glossary........................................................................................................... 729
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Application manual