Example How To Connect Delta Connected Three-Phase Ct Set To The Ied - ABB Relion 670 Series Applications Manual

Section 4
Analog inputs
5)
6)
4.2.2.6

Example how to connect delta connected three-phase CT set to the IED

Figure 28
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.
78
is a connection made in the Signal Matrix tool (SMT), 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. In that case the pre-processing block will calculate it by vectorial summation of
the three individual phase currents.
is a Preprocessing block that has the task to digitally filter the connected analog inputs and calculate:
• fundamental frequency phasors for all four input channels
• harmonic content for all four input channels
• positive, negative and zero sequence quantities by using the fundamental frequency phasors for
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.
gives an example how to connect a delta connected three-phase CT set to the IED. It
For correct terminal designations, see the connection diagrams valid for the
delivered IED.
1MRK 511 358-UUS A
SEMOD55055-392 v7
Application manual