ABB REG316 4 Series - Inverse Definite Minimum Time Earth Fault Overcurrent Function

REG 316*4 1MRB520049-Uen / Rev. F ABB Switzerland Ltd
3-271
3.5.27. Inverse definite minimum time earth fault overcurrent
function (I0-Invers)
A. Application
Overcurrent function with IDMT characteristic. A typical applica-
tion is as back-up for the E/F protection function, in which case it
measures 3 I
0
either supplied from an external source or inter-
nally derived.
B. Features
· Tripping characteristic according to British Standard 142
(see Fig. 3.5.27.1):
c = 0.02 : normal inverse
c = 1 : very inverse and long time earth fault
c = 2 : extremely inverse.
· DC component filter
· harmonic filter
· external 3 I
0
signal or 3 I
0
internally derived from the three
phase currents
· wider setting range than specified in BS 142.
C. Inputs and outputs
I. C.t./v.t. inputs
· Current
II. Binary inputs
· Blocking
III. Binary outputs
· Starting
· Tripping
IV. Measurements
· Neutral current.