APPENDIX
355
NVA100X-D - Manual - 02 - 2016
Directional ground overcurrent 67N(Comp) - Very inverse time curve (ANSI/IEEE type VI)
—
F_67N(Comp)-ANSIVI-Char.ai
1.1
2
3
4
5
6
7
8 9 10
20
0.01
0.1
1
10
100
1000
10000
t
[s]
10 s
60 s
5 s
1 s
0.5 s
0.2 s
0.1 s
0.02 s
Note: match of operating and setting time takes place when I
EDH
/I
EDC
>
inv
or I
EDL
/I
EDC
>
inv
= 2.306
I
EDH
/
I
EDC
>inv
I
EDL
/
I
EDC
>inv
t
=
t
EDC
>
inv
·
[(
I
EDH
/
I
EDC
>
inv
)
2
-1]
3.922
+ 0.092
t
=
t
EDC
>
inv
t
EDC
>
inv
·
[(
I
EDL
/
I
EDC
>
inv
)
2
-1]
3.922
+ 0.092