Thytronic NA30 - Ground Directional Overcurrent 67 N - Standard Inverse Time Curve (IEC 60255-3;BS142 Type A)

APPENDIX
168
NA30 - Manual - 04 - 2022
 Ground directional overcurrent 67N - Standard inverse time curve (IEC 60255-3/BS142 type A)
F_67N-IECA-Char.ai
1.1
2 3 4 5 6 7 8 9 10 20
I
ED
/I
ED
>
I
ED
/I
ED
>>
0.01
0.1
1
10
100
1000
10000
t [s]
t
ED
>
inv
= 10 s
t
ED
>>
inv
= 10 s
t
ED
>
inv
= 60 s
t
ED
>>
inv
= 60 s
t
PD
>
inv
= 5 s
t
ED
>>
inv
= 5 s
t
ED
>
inv
= 1 s
t
ED
>>
inv
= 1 s
t
ED
>
inv
= 0.5 s
t
ED
>>
inv
= 0.5 s
t
ED
>
inv
= 0.2 s
t
ED
>>
inv
= 0.2 s
t
ED
>
inv
= 0.1 s
t
ED
>>
inv
= 0.1 s
t
ED
>
inv
= 0.02 s
t
ED
>>
inv
= 0.02 s
Note: match of operating and setting time takes place when I
ED
/I
ED
>
inv
= 700 or I
ED
/I
ED
>>
inv
= 700
t =
t
ED
>>
inv
·
[(I
ED
/I
ED
>>
inv
)
0.02
-1]
0.14
t =
t
ED
>
inv
·
[(I
ED
/I
ED
>
inv
)
0.02
-1]
0.14