Example How To Connect The Open Delta Vt To The Ied For Low Impedance Grounded Or Solidly Grounded Power Systems - ABB Relion 670 Series Applications Manual

1MRK 511 358-UUS A
Where:
1)
2)
3)
4)
5)
4.2.4.6 Example how to connect the open delta VT to the IED for low impedance
grounded or solidly grounded power systems
Figure 35
grounded or solidly grounded power systems. It shall be noted that this type of VT connection
presents secondary voltage proportional to 3V
Application manual
shows how to connect the secondary side of the open delta VT to one VT input on the IED.
+3Vo shall be connected to the IED
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 11.43
EQUATION1923 V1 EN-US
110
= × =
VT sec 3 110 V
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
3
=
110
110
3
EQUATION1925 V1 EN-US
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
connect 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 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
accordingly.
gives an example about the connection of an open delta VT to the IED for low impedance
kV
to the IED.
0
Analog inputs
(Equation 4)
(Equation 5)
(Equation 6)
DFTReference shall be set
SEMOD55055-199 v6
Section 4
89