ABB Relion 670 series - Principle of operation; Function block; Input and output signals

13.8.8.2 Principle of operation
Negative sequence overcurrent protection (LCNSPTOC, 46) is a definite time stage
comparator function. The negative sequence input current from the SMAI block is
connected as input to the function through a group connection I3P in PCM600. This
current is compared against the preset value and a pickup signal will be set high if the
input negative sequence current is greater than the preset value Pickup2. Trip signal
will be set high after a time delay setting of tI2. BLOCK input will block the complete
function. BLKTR will block the trip output. The negative sequence current is available
as service value output I2.
13.8.8.3 Function block
ANSI09000769-1-en.vsd
LCNSPTOC (46)
I3P*
BLOCK
BLKTR
TRIP
RI
ANSI09000769 V1 EN
Figure 423: LCNSPTOC (46) Function block
13.8.8.4 Input and output signals
Table 475: LCNSPTOC (46) Input signals
Name
Type Default Description
I3P GROUP
SIGNAL
- Three phase group signal for current inputs
BLOCK BOOLEAN 0 Block overall function
BLKTR BOOLEAN 0 Block trip signal
Table 476: LCNSPTOC (46) Output signals
Name
Type Description
TRIP BOOLEAN Trip signal negative sequence over current protection
RI BOOLEAN Start signal for negative sequence over current
protection
1MRK505222-UUS C Section 13
Scheme communication
849
Technical reference manual