ABB RET670 Product Manual page 79

ABB
Transformer protection RET670 ANSI
Pre-configured
Product version: 1.2
Table 80. RI and RD type inverse time characteristics
Function
RI type inverse characteristic
1
= ×
t td
0.236
-
0.339
I
EQUATION1656 V1 EN
I = I /I
measured set
RD type logarithmic inverse characteristic
æ ö
I
- ç × ÷
= 5.8 1.35 In
t
è ø
td
EQUATION1657 V1 EN
I = I /I
measured set
Range or value
td = (0.05-999) in steps of 0.01
td = (0.05-999) in steps of 0.01
1MRK 504 118-BUS A
Accuracy
IEC 60255-3, class 5 +
40 ms
IEC 60255-3, class 5 +
40 ms
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