ABB Relion 670 Series Applications Manual page 476

Section 20
Basic IED functions
However, this configuration, combined with unbalanced three-phase input, results in incorrect calculated
phase-earth values.
This in turn may result in maloperation of functions connected to SMAIs configured in this way, if the
function uses phase-earth based values.
Further, if SUM3PH is connected to such a SMAI, then its output values will be incorrect, and the
connected functions may maloperate.
To rectify this situation, revise the configuration from this perspective.
20.11.4 Setting guidelines
The parameters for the signal matrix for analog inputs (SMAI) functions are set via the local HMI or
PCM600.
Every SMAI function block can receive four analog signals (three phases and one neutral value), either
voltage or current. SMAI outputs give information about every aspect of the 3ph analog signals acquired
(phase angle, RMS value, frequency and frequency derivates, and so on – 244 values in total). Besides
the block "group name", the analog inputs type (voltage or current) and the analog input names can be
set directly in ACT.
Application functions should be connected to a SMAI block with same task cycle as the application
function, except for e.g. measurement functions that run in slow cycle tasks.
DFTRefExtOut: Parameter valid only for function block SMAI1 .
Reference block for external output (SPFCOUT function output).
DFTReference: Reference DFT for the SMAI block use.
These DFT reference block settings decide DFT reference for DFT calculations. The setting
InternalDFTRef will use fixed DFT reference based on set system frequency. DFTRefGrp(n) will use DFT
reference from the selected group block, when own group is selected, an adaptive DFT reference will be
used based on calculated signal frequency from own group. The setting ExternalDFTRef will use
reference based on what is connected to input DFTSPFC.
The setting ConnectionType: Connection type for that specific instance (n) of the SMAI (if it is Ph-N or
Ph-Ph). Depending on connection type setting the not connected Ph-N or Ph-Ph outputs will be
calculated as long as they are possible to calculate. E.g. at Ph-Ph connection A, B and C 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 Negate3Ph, only the neutral signal NegateN or both Negate3Ph+N. negation means rotation with
180° of the vectors.
GlobalBaseSel: Selects the global base value group used by the function to define (IBase), (VBase) and
(SBase).
MinValFreqMeas: The minimum value of the voltage for which the frequency is calculated, expressed as
percent of VBase (for each instance n).
470
/V must be connected to input 4.
N N
Settings DFTRefExtOut and DFTReference shall be set to default value InternalDFTRef
if no VT inputs are available.
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