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Section 20
Basic IED functions
L2 and L3 will be calculated for use in symmetrical situations. If N component should be used
respectively the phase component during faults I
Negation : If the user wants to negate the 3ph signal, it is possible to choose to negate only the
phase signals
means rotation with 180° of the vectors.
GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ),
UBase ) and ( SBase ).
(
MinValFreqMeas : The minimum value of the voltage for which the frequency is calculated,
expressed as percent of UBase (for each instance n).
Examples of adaptive frequency tracking
438
Negate3Ph , only the neutral signal NegateN or both Negate3Ph+N . negation
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
/U
must be connected to input 4.
N
N
AnalogInputType of a SMAI block to " Current ", the
1MRK 505 370-UEN D
Busbar protection REB670
Application manual
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