setting must still be Ph-Ph and this has to be accounted for when
setting IntBlockLevel. If SMAI setting ConnectionType is Ph-N and the
same voltage is connected to all three SMAI inputs, the positive
sequence voltage will be zero and the frequency functions will not
work properly.
The outputs from the above configured SMAI block shall only be used
for Overfrequency protection (SAPTOF, 81), Underfrequency
protection (SAPTUF, 81) and Rate-of-change frequency protection
(SAPFRC, 81) due to that all other information except frequency and
positive sequence voltage might be wrongly calculated.
3.4.12.3 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 that can be set
directly in ACT.
Instantaneous protection function with a 3 ms cycle time, needs to be connected to the
processing SMAI function block, which is also running at 3 ms task cycle. In addition,
logic function blocks used with these fast cycle protection functions need to have 3 ms
task cycle. Same procedure needs to be followed for each cycle time.
DFTRefExtOut: Parameter valid only for function block SMAI1 .
Reference block for external output (SPFCOUT function output).
DFTReference: Reference DFT for the block.
These DFT reference block settings decide DFT reference for DFT calculations. The
settings InternalDFTRef will use fixed DFT reference based on set system frequency.
AdDFTRefChn will use DFT reference from the selected group block, when own
group selected 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.
1MRK504116-UUS C Section 3
IED application
89
Application manual
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