ABB Relion RES670, Technical Manual, Page: 798 / 934

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.
22.10 Summation block 3 phase 3PHSUM
SEMOD55968-1 v2
22.10.1 Functionality
SEMOD55976-4 v4
Summation block 3 phase function 3PHSUM is used to get the sum of two sets of
three-phase analog signals (of the same type) for those IED functions that might need
it.
22.10.2 Function block
SEMOD54885-4 v3
3PHSUM
BLOCK
REVROT
^G1AI3P*
^G2AI3P* AI3P
AI1
AI2
AI3
AI4
IEC05000441-3-en.vsdx
IEC05000441 V3 EN-US
Figure 304: 3PHSUM function block
Section 22
1MRK 511 408-UUS A
Basic IED functions
792 Phasor measurement unit RES670 2.2 ANSI
Technical manual