ABB RELION RET670 Applications Manual page 100

Section 4
Analog inputs
94
Where:
1) shows how to connect the secondary side of the open delta VT to one VT input on the IED.
2) is the TRM where this voltage input is located. It shall be noted that for this voltage input the
following setting values shall be entered:
= ×
VTprim 3 6.6
EQUATION1923 V1 EN-US
110
= ×
VT sec 3
3
EQUATION1924 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 one individual open delta VT.
6.6
×
3 6.6
=
110
110
EQUATION1925 V1 EN-US
3) shows that in this example the first three input channel of the preprocessing block is not
connected in SMT tool or ACT tool.
4) shows the connection made in Signal Matrix Tool (SMT), Application configuration tool
(ACT), which connect this voltage input to the fourth input channel of the preprocessing
function block 5).
5) is a Preprocessing block that has the task to digitally filter the connected analog input 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
be set accordingly.
+3Vo shall be connected to the IED
=
11.43 kV
=
110 V
3
3
1MRK 504 163-UUS A
(Equation 4)
(Equation 5)
(Equation 6)
DFTReference shall
Transformer protection RET670 2.2 ANSI
Application manual