ABB RET670 Product Manual page 77

ABB
Transformer protection RET670 ANSI
Pre-configured
Product version: 1.2
Inverse characteristic
Table 78. ANSI Inverse time characteristics
Function
Operating characteristic:
æ ö
A
ç ÷
= + ×
t B td
( )
ç ÷
P
è - ø
I 1
EQUATION1651 V1 EN
Reset characteristic:
t r
= ×
t td
( )
2
-
I 1
EQUATION1652 V1 EN
I = I /I
measured set
ANSI Extremely Inverse
ANSI Very inverse
ANSI Normal Inverse
ANSI Moderately Inverse
ANSI Long Time Extremely Inverse
ANSI Long Time Very Inverse
ANSI Long Time Inverse
Range or value
td = (0.05-999) in steps of 0.01 unless otherwise
stated
A=28.2, B=0.1217, P=2.0 , tr=29.1
A=19.61, B=0.491, P=2.0 , tr=21.6
A=0.0086, B=0.0185, P=0.02, tr=0.46
A=0.0515, B=0.1140, P=0.02, tr=4.85
A=64.07, B=0.250, P=2.0, tr=30
A=28.55, B=0.712, P=2.0, tr=13.46
td=(0.05-999) in steps of 0.01
A=0.086, B=0.185, P=0.02, tr=4.6
1MRK 504 118-BUS A
Accuracy
-
ANSI/IEEE C37.112,
class 5 + 40 ms
77