Hitachi Relion 670 Series Applications Manual page 59

1MRK511407-UUS Rev. N
Where:
1)
2)
3)
4)
Another alternative is to have the delta connected CT set as shown in Figure 16:
Phasor measurement unit RES670
Application manual
shows how to connect three individual phase currents from a delta connected three-phase CT set to three CT
inputs of the IED.
is the TRM where these current inputs are located. It shall be noted that for all these current inputs the following
setting values shall be entered.
CT =600A
prim
CT =5A
sec
• CTWyePoint=ToObject
• ConnectionType=Ph-Ph
are three connections made in Signal Matrix Tool (SMT), Application configuration tool (ACT), which connect
these three current inputs to first three input channels of the preprocessing function block 4). Depending on the
type of functions which need this current information, more then one preprocessing block might be connected in
parallel to these three CT inputs.
is a Preprocessing block that has the task to digitally filter the connected analog inputs and calculate:
• fundamental frequency phasors for all three input channels
• harmonic content for all three 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. 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 DFTReference shall be set accordingly.
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Section 4
Analog inputs
53