ABB REG670 - Page 1261

Table 962: ANSI Inverse time characteristics for Line Differential Protection
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 ,
± 5.0% 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
1255
Technical manual