Line Differential Protection 3 Or 6 Ct Sets, With In-Zone Transformers - ABB RED670 Product Manual

Line differential protection RED670 ANSI
Customized
Product version: 1.2
Line differential protection 3 or 6 CT sets, with in-zone
transformers LT3CPDIF, LT6CPDIF (87LT)
Two two-winding power transformers, or one three-winding
power transformer, can be included in the line differential
IED
Communication Channel
IED
ANSI05000042 V2 EN
Figure 3. 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
communication channel is needed between every IED included
in the same line differential protection zone. In the latter, current
samples are sent from all slave IEDs to one master IED where
the evaluation is made, and trip signals are sent to the remote
12
Protected zone
Communication Channel
Communication Channel
protection zone. Both two- and three-winding transformers are
correctly represented with phase shift compensations made in
the algorithm. The function includes 2
restraint and zero-sequence current elimination.
IED
ANSI0500042_2_en.vsd
ends when needed. In this system, a 64 kbit/s communication
channel is only needed between the master, and each one of
the slave IEDs.
It is recommended to use the same firmware
version as well as hardware version for a
specific RED670 scheme.
1MRK505226-BUS D
nd th
and 5 harmonic
ABB