ABB REG670 - Inverse Characteristics

In version 2.0, a typical starting time delay of 24ms is subtracted from
the set trip time delay, so that the resulting trip time will take the
internal IED start time into consideration.
25.3 Inverse characteristics
Table 959: ANSI Inverse time characteristics
Function Range or value Accuracy
Operating characteristic:
( )
1
P
A
t B k tDef
I
æ ö
ç ÷
= + × +
ç ÷
ç - ÷
è ø
EQUATION1249-SMALL V2 EN
Reset characteristic:
( )
2
1
= ×
-
t
r
t k
I
EQUATION1250-SMALL V1 EN
I = I
measured
/I
set
k = (0.05-2.00) in steps of 0.01 ANSI/IEEE C37.112 ,
± 2.0% or ± 40 ms
whichever is greater
ANSI Extremely Inverse A=28.2, B=0.1217, P=2.0 ,
tr=29.1
ANSI Very inverse A=19.61, B=0.491, P=2.0 ,
tr=21.6
ANSI Normal Inverse A=0.0086, B=0.0185, P=0.02,
tr=0.46
ANSI Moderately Inverse A=0.0515, B=0.1140, P=0.02,
tr=4.85
ANSI Long Time Extremely Inverse A=64.07, B=0.250, P=2.0,
tr=30
ANSI Long Time Very Inverse A=28.55, B=0.712, P=2.0,
tr=13.46
ANSI Long Time Inverse A=0.086, B=0.185, P=0.02,
tr=4.6
1MRK502052-UEN B Section 25
Inverse time characteristics
1253
Technical manual