ABB Relion 670 Series Applications Manual page 333

1MRK 511 407-UUS Rev. J
Examples of adaptive frequency tracking
Phasor measurement unit RES670
Application manual
DFTRefExtOut and DFTReference shall be set to default value
Settings
InternalDFTRef if no VT inputs are available.
Even if the user sets the
MinValFreqMeas is still visible. However, using the current channel values as base
for frequency measurement is not recommendable for a number of reasons, not
last among them being the low level of currents that one can have in normal
operating conditions.
Preprocessing block shall only be used to feed functions within the same execution
cycles (e.g. use preprocessing block with cycle 1 to feed transformer differential
protection). The only exceptions are measurement functions (CVMMXN,
CMMXU,VMMXU, etc.) which shall be fed by preprocessing blocks with cycle 8.
When two or more preprocessing blocks are used to feed one protection function
(e.g. over-power function GOPPDOP), it is of outmost importance that parameter
setting DFTReference has the same set value for all of the preprocessing blocks
involved
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AnalogInputType of a SMAI block to " Current ", the
Section 22
Basic IED functions
327