ABB REB670 Applications Manual page 175

1MRK 505 337-UUS -
Application manual
HarmRestrainx: This parameter can be set Disabled/Enabled, to disable or enable the 2nd
harmonic restrain.
The four step phase overcurrent protection 3-phase output can be used in different ways,
depending on the application where the protection is used. A general description is given
below.
The pickup current setting of the inverse time protection, or the lowest current step of the
definite time protection, must be defined so that the highest possible load current does not
cause protection operation. Here consideration also has to be taken to the protection reset
current, so that a short peak of overcurrent does not cause operation of the protection even
when the overcurrent has ceased. This phenomenon is described in figure 79.
Current I
Pickup current
Reset current
The IED does not reset
ANSI09000146 V1 EN
Figure 79: Pickup and reset current for an overcurrent protection
The lowest setting value can be written according to equation 28.
Section 7
Current protection
Line phase current
Time t
ANSI09000146-en-1.vsd
169