ABB RELION RET670, Applications Manual

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5) Is a connection made in the Signal Matrix tool (SMT) and Application configuration tool (ACT),
which connects the residual/neutral current input to the fourth input channel of the
preprocessing function block 6). Note that this connection in SMT shall not be done if the
residual/neutral current is not connected to the IED.
6) Is a Preprocessing block that has the task to digitally filter the connected analog inputs and
calculate:
• fundamental frequency phasors for all input channels
• harmonic content for all input channels
• positive, negative and zero sequence quantities by using the fundamental frequency
phasors of the first three input channels (channel one taken as reference for sequence
quantities)
These calculated values are then available for all built-in protection and control functions within
the IED, which are connected to this preprocessing function block in the configuration tool. For
this application, most of the preprocessing settings can be left to the default values.
If frequency tracking and compensation is required (this feature is typically required only for
IEDs installed in the generating stations), then the setting parameters DFTReference shall be
set accordingly.
4.2.2.6 Example how to connect delta connected three-phase CT set to the IED
SEMOD55055-392 v7
Figure 17 gives an example how to connect a delta connected three-phase CT set to the
IED. It gives an overview of the required actions by the user in order to make this
measurement available to the built-in protection and control functions in the IED as
well.
For correct terminal designations, see the connection diagrams valid for
the delivered IED.
1MRK 504 163-UUS A
Section 4
Analog inputs
Transformer protection RET670 2.2 ANSI 81
Application manual