ABB ret650 - Page 640

Table 564: Inverse time characteristics for residual overvoltage protection
Function Range or value Accuracy
Type A curve:
=
- >
>
æ ö
ç ÷
è ø
t
k
U U
U
EQUATION1436-SMALL V1 EN
U> = U
set
U = U
measured
k = (0.05-1.10) in steps of
0.01
±5% +70 ms
Type B curve:
2.0
480
32 0.5 0.035
=
×
- >
× - -
>
æ ö
ç ÷
è ø
t
k
U U
U
EQUATION1437-SMALL V1 EN
k = (0.05-1.10) in steps of
0.01
Type C curve:
3.0
480
32 0.5 0.035
=
×
- >
× - -
>
æ ö
ç ÷
è ø
t
k
U U
U
EQUATION1438-SMALL V1 EN
k = (0.05-1.10) in steps of
0.01
Section 21 1MRK 504 135-UEN A
Time inverse characteristics
634
Technical manual