ABB REG316 4 Series Operating Instructions Manual page 314

ABB Switzerland Ltd
Interconnections between IDMT and directional E/F func-
tions
The IDMT protection is non-directional.
Directional operation can, however, be achieved by linking the
directional signal ( 'MeasFwd', i.e. fault in forwards direction)
from the E/F protection to the blocking I/P of the IDMT function.
The I/P must be inverted so that blocking of the IDMT function is
cancelled by an active forwards signal.
When using this arrangement, it must be noted that, when
'MeasFwd' does not pick up, the IDMT function cannot trip when
the reference voltage of the E/F function is too low. If tripping is
required for this case, the directional E/F signal 'MeasBwd' must
be applied to the blocking input.
Applications with single-phase reclosure
In schemes involving single-phase reclosure, the 'I0-Invers'
function has to be blocked for the time that one pole of a circuit-
breakers is open if the minimum tripping time 'tmin' is set less
than the single-phase dead time. This avoids false three-phase
tripping due to the load currents in the healthy phases.
Typical settings:
IB
I-Start
c
k1
t-min.
3-276
REG 316*4 1MRB520049-Uen / Rev. F
to be calculated
1.1 IB
depends on the protected unit
to be calculated
0.00