Example On How To Connect A Phase-To-Phase Connected Vt To The Ied - ABB Relion 670 Series Applications Manual

1MRK 511 358-UUS A
3)
4)
5)
4.2.4.4

Example on how to connect a phase-to-phase connected VT to the IED

Figure 33
overview of the required actions by the user in order to make this measurement available to the
built-in protection and control functions within the IED as well. It shall be noted that this VT
connection is only used on lower voltage levels (that is, rated primary voltage below 40 kV).
Application manual
are three connections made in Signal Matrix Tool (SMT), which connect these three voltage inputs to
first three input channels of the preprocessing function block 5). Depending on the type of functions
which need this voltage information, more then one preprocessing block might be connected in
parallel to these three VT inputs.
shows that in this example the fourth (that is, residual) input channel of the preprocessing block is
not connected in SMT tool. Thus the preprocessing block will automatically calculate 3Vo inside by
vectorial sum from the three phase to ground voltages connected to the first three input channels of
the same preprocessing block. Alternatively, the fourth input channel can be connected to open delta
VT input, as shown in figure 34.
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. However the
following settings shall be set as shown here:
VBase=66 kV (that is, rated Ph-Ph voltage)
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 how to connect a phase-to-phase connected VT to the IED. It gives an
Analog inputs
DFTReference shall be set
SEMOD55055-134 v6
Section 4
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