ABB REB650 - Negative Sequence Based

will not be activated until after 200 ms. This means that distance functions are not
blocked and due to the “no voltage but current” situation might issue a trip.
The operation mode selector OpMode has been introduced for better adaptation to
system requirements. The mode selector enables selecting interactions between the
negative sequence and zero sequence algorithm. In normal applications, the
OpMode is set to either UNsINs for selecting negative sequence algorithm or
UZsIZs for zero sequence based algorithm. If system studies or field experiences
shows that there is a risk that the fuse failure function will not be activated due to
the system conditions, the dependability of the fuse failure function can be
increased if the OpMode is set to UZsIZs OR UNsINs or OptimZsNs. In mode
UZsIZs OR UNsINs both negative and zero sequence based algorithms are
activated and working in an OR-condition. Also in mode OptimZsNs both negative
and zero sequence algorithms are activated and the one that has the highest
magnitude of measured negative or zero sequence current will operate. If there is a
requirement to increase the security of the fuse failure function OpMode can be
selected to UZsIZs AND UNsINs which gives that both negative and zero sequence
algorithms are activated and working in an AND-condition, that is, both algorithms
must give condition for block in order to activate the output signals BLKU or
BLKZ.
9.1.3.3 Negative sequence based
M13683-17 v9
The relay setting value 3U2> is given in percentage of the base voltage UBase and
should not be set lower than the value that is calculated according to equation 36.
100
3
2
23 
UBase
U
U
EQUATION1519 V5 EN-US (Equation 36)
where:
U2 is the maximal negative sequence voltage during normal operation conditions, plus a margin
of 10...20%
UBase is the base voltage for the function according to the setting GlobalBaseSel
The setting of the current limit 3I2< is in percentage of parameter IBase. The
setting of 3I2< must be higher than the normal unbalance current that might exist
in the system and can be calculated according to equation 37.
100
2
23 
IBase
I
I
EQUATION1520 V5 EN-US (Equation 37)
where:
I2 is the maximal negative sequence current during normal operating conditions, plus a margin
of 10...20%
IBase is the base current for the function according to the setting GlobalBaseSel
1MRK 505 388-UEN B Section 9
Secondary system supervision
Busbar protection REB650 2.2 IEC 147
Application manual