Woodward highprotec MRI4, User Manual

Page: 425 / 727

Protective Elements
ANSI Extremely Inverse
Various reset modes are available:
Resetting via characteristic, delayed and instantaneous.
Remark: For
I > 20⋅I
>
, the curve stops decreasing, the t-values are kept constant at the value for
I = 20⋅I
>
.
425 MRI4 DOK-HB-MRI4-2E
0.5
1
2
5
10
15
0.01 0.1
1 10 100
0.1
1
10
100
1000
t [s]
I / I> (multiples of pickup)
tchar=
Pd
o
c
_Z
0
7
»Char« = ANSI EINV
Reset Trip
t
−1
28.2
=
I
I>
2
tchar + 0.1217
t
1−
29.1
=
I
I>
2
tchar
≤ 20 If:
I
I>
1 < If: < 1
I
I>