Frequency Values - ABB RES670 Applications Manual

Section 22
Basic IED functions
22.11.2
342

Frequency values

The SMAI function includes a functionality based on the level of positive sequence
voltage, MinValFreqMeas, to validate if the frequency measurement is valid or not.
If the positive sequence voltage is lower than MinValFreqMeas, the function
freezes the frequency output value for 500 ms and after that the frequency output is
set to the nominal value. A signal is available for the SMAI function to prevent
operation due to non-valid frequency values. MinValFreqMeas is set as % of
UBase/√3
If SMAI setting ConnectionType is Ph-Ph, at least two of the inputs GRPxL1,
GRPxL2 and GRPxL3, where 1≤x≤12, must be connected in order to calculate the
positive sequence voltage. Note that phase to phase inputs shall always be
connected as follows: L1-L2 to GRPxL1, L2-L3 to GRPxL2, L3-L1 to GRPxL3. If
SMAI setting ConnectionType is Ph-N, all three inputs GRPxL1, GRPxL2 and
GRPxL3 must be connected in order to calculate the positive sequence voltage.
If only one phase-phase voltage is available and SMAI setting ConnectionType is
Ph-Ph, the user is advised to connect two (not three) of the inputs GRPxL1,
GRPxL2 and GRPxL3 to the same voltage input as shown in figure
SMAI calculate a positive sequence voltage.
BLOCK
DFTSPFC
UL1L2
REVROT
PHASEL1
^GRP1L1
TRM_40.CH7(U)
PHASEL2
^GRP1L2
PHASEL3
^GRP1L3
NEUTRAL
^GRP1N
IEC10000060 V3 EN-US
Figure 118: Connection example
The above described scenario does not work if SMAI setting
ConnectionType is Ph-N. If only one phase-earth 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), Underfrequency
protection (SAPTUF) and Rate-of-change frequency protection
SMAI1
SPFCOUT
G1AI3P
U3P*
BLOCK
G1AI1
BLKTRIP
G1AI2
G1AI4
G1N
1MRK 511 407-UEN C
GUID-B494B93C-B5AA-4FD6-8080-8611C34C2AD8 v5
118 to make
SAPTOF
TRIP
START
BLKDMAGN
FREQ
Phasor measurement unit RES670 2.2 IEC
Application manual
SAPTOF(1)_TRIP
EC10000060-3-en.vsdx