Line Differential Protection 3 Or 6 Ct Sets, With In-Zone Transformers Lt3Cpdif, Lt6Cpdif; Analog Signal Transfer For Line Differential Protection - ABB Relion 670 Series Technical Reference Manual

Section 5
Differential protection
5.1.1.2
5.1.1.3
124
A line charging current compensation provides increased sensitivity of Line differential
protection.
Line differential protection 3 or 6 CT sets, with in-zone transformers
LT3CPDIF, LT6CPDIF
Two two-winding power transformers, or one three-winding power transformer, can be
included in the line differential protection zone. Both two- and three-winding
transformers are correctly represented with phase shift compensations made in the
algorithm. The function includes 2
current elimination.
IED
Communication Channel
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ANSI05000042 V2 EN
Figure 48: Example of application on a three-terminal line with a power
transformer in the protection zone

Analog signal transfer for line differential protection

The line differential communication can be arranged as a master-master system or a
master-slave system alternatively. In the former, current samples are exchanged
between all IEDs, and an evaluation is made in each IED. This means that a 64 kbit/s
nd th
and 5 harmonic restraint and zero-sequence
Protected zone
Communication Channel
Communication Channel
1MRK505222-UUS C
IED
ANSI0500042_2_en.vsd
Technical reference manual