ABB RELION RET670, Applications Manual

Page: 977 / 1016

The above described scenario does not work if SMAI setting
ConnectionType is Ph-N . If only one phase-ground voltage is available,
the same type of connection can be used but the SMAI ConnectionType
setting must still be Ph-Ph and this has to be accounted for when
setting MinValFreqMeas . 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.
24.11.3 Setting guidelines
GUID-C8D6C88B-87C6-44C1-804B-CF1594365EE6 v8
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.
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.
1MRK 504 163-UUS A
Section 24
Basic IED functions
Transformer protection RET670 2.2 ANSI 971
Application manual