Function Block - ABB REG650 Technical Manual

Section 8
Current protection
8.9.3
8.9.4
238
To provide an effective protection for the generator for external unbalanced conditions,
NS2PTOC (46I2) is able to directly measure the negative sequence current. NS2PTOC
(46I2) also has a time delay characteristic which matches the heating characteristic of
2
=
I t K
the generator as defined in standard IEEE C50.13.
2
where:
I
2
t
K
NS2PTOC (46I2) has a wide range of K settings and the sensitivity and capability of
detecting and tripping for negative sequence currents down to the continuous capability
of a generator.
A separate output is available as an alarm feature to warn the operator of a potentially
dangerous situation.

Function block

NS2PTOC (46I2)
I3P* TRIP
BLOCK TRST1
BLK1 TRST2
BLK2 PICKUP
PU_ST1
PU_ST2
ALARM
NSCURR
ANSI08000359-2-en.vsd
ANSI08000359 V2 EN
Figure 109: NS2PTOC (46I2) function block
Signals
Table 124: NS2PTOC (46I2) Input signals
Name Type
I3P GROUP
SIGNAL
BLOCK BOOLEAN
BLK1 BOOLEAN
BLK2 BOOLEAN
is negative sequence current expressed in per unit of the rated
generator current
is operating time in seconds
is a constant which depends of the generators size and design
Default Description
- Group connection for neg seq.
0 Block of function
0 Block of step 1
0 Block of step 2
1MRK 502 043-UUS B
Technical Manual