ABB Relion REQ650, Руководство по применению

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3) 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.
4) 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 3Uo inside by vectorial sum from the three phase to earth voltages connected to
the first three input channels of the same preprocessing block. .
4) 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:
UBase=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
DFTReference
shall be set accordingly.
4.2.4.4 Example on how to connect a phase-to-phase connected VT to the IED
Figure 31 gives an example how to connect a phase-to-phase connected VT to the
IED. It 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 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).
For correct terminal designations, see the connection diagrams valid
for the delivered IED.
Section 4
1MRK 505 291-UEN A
Analog inputs
74
Application manual