ABB REG670 - Page 1265

Table 967: RI and RD type inverse time characteristics for Sensitive directional residual
overcurrent and power protection
Function Range or value Accuracy
RI type inverse characteristic
1
0.236
0.339
= ×
-
t k
I
EQUATION1137-SMALL V1 EN
I = I
measured
/I
set
0.10 ≤ k ≤ 2.00
1.5 x I
set
≤ I ≤ 20 x I
set
IEC 60255-151, ±5.0%
or ±160 ms whichever is
greater
RD type logarithmic inverse characteristic
5.8 1.35= - ×
æ ö
ç ÷
è ø
t
I
In
k
EQUATION1138-SMALL V1 EN
I = I
measured
/I
set
Table 968: ANSI Inverse time characteristics for Voltage restrained time overcurrent 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
0.10 ≤ k ≤ 3.00 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
1259
Technical manual