ABB Relion REC670 Applications Manual page 82

Section 4
Analog inputs
Where:
1)
2)
3)
4)
5)
76
shows how to connect the secondary side of neutral point VT to one VT input in the IED.
U shall be connected to the IED.
0
is the TRM or AIM where this voltage input is located. For this voltage input the following setting
values shall be entered:
6.6
= =
VTprim 3.81 kV
3
EQUATION1933 V1 EN-US
=
VT sec 100 V
EQUATION1934 V1 EN-US
Inside the IED, only the ratio of these two parameters is used. It shall be noted that the ratio of the
entered values exactly corresponds to ratio of the neutral point VT.
shows that in this example the first three input channel of the preprocessing block is not connected
in SMT tool or ACT tool.
shows the connection made in Signal Matrix Tool (SMT), Application configuration tool (ACT), which
connects this voltage input to the fourth input channel of the preprocessing function block 5).
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
accordingly.
1MRK 511 358-UEN A
(Equation 12)
(Equation 13)
DFTReference shall be set
Application manual