Thytronic Pro-N NVA100X-D - Directional Ground Overcurrent 67 N - Extremely Inverse Time Curve (ANSI;IEEE Type EI)

APPENDIX
353
NVA100X-D - Manual - 02 - 2016
Directional ground overcurrent 67N - Extremely inverse time curve (ANSI/IEEE type EI)—
F_67N-ANSIEI-Char.ai
1.1
2 3 4 5 6 7 8 9 10 20
I
ED
/I
ED
>inv
0.01
0.1
1
10
100
1000
10000
t [s]
10 s
60 s
t
ED
>
inv
5 s
t
ED
>
inv
= 0.5 s
t
ED
>
inv
= 1 s
t
ED
>
inv
= 0.2 s
t
ED
>
inv
= 0.1 s
t
ED
>
inv
= 0.02 s
t =
t
ED
>
inv
·
[(I
ED
/I
ED
>
inv
)
2
-1]
5.64
+ 0.024
Note: match of operating and setting time takes place when I
ED
/I
ED
>
inv
= 2.789