ABB REB670 Series Applications Manual page 76

Section 4
Analog inputs
4)
5)
6)
4.2.2.6 Example how to connect delta connected three-phase CT set to the IED
Figure 23
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.
70
Are three connections made in the Signal Matrix tool (SMT) and Application configuration tool
(ACT), which connects these three current inputs to the first three input channels on the
preprocessing function block 6). Depending on the type of functions, which need this current
information, more than one preprocessing block might be connected in parallel to these three CT
inputs.
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.
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.
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 505 370-UEN D
SEMOD55055-392 v7
Busbar protection REB670
Application manual