Micom P631, Technical Manual, Page: 189 / 638

3.23.2 Time-Dependent Characteristics
The measuring systems for phase currents, residual current and negative-
sequence current operate independently of each other and can be set
separately. The user can select from a large number of characteristics (see table
below). The measured variable is the maximum phase current, the negative-
sequence current, or the residual current, depending on the measuring system.
The tripping characteristics available for selection are shown in the following
figures (
Fig. 3-99, (p. 3-134) to Fig. 3-102, (p. 3-136) ).
0 Definite Time t = k
Per IEC 255–3
t = k ·
a
(
I
I
ref
)
b
- 1
1 Standard Inverse 0.14 0.02
2 Very Inverse 13.50 1.00
3 Extremely Inverse 80.00 2.00
4 Long Time Inverse 120.00 1.00
Per IEEE C37.112 t = k · (
a
(
I
I
ref
)
b
- 1
+ c ) t
r
=
k · R
(
I
I
ref
)2 - 1
Per ANSI t = k · (
a
(
I
I
ref
)
b
- 1
+ c ) t
r
=
k · R
(
I
I
ref
)2 - 1
11 RI-Type Inverse t = k ·
1
0.339 -
0.236
(
I
I
ref
)
12 RXIDG-Type Inverse
t = k · (5.8 - 1.35 · ln
I
I
ref
)
5 Moderately Inverse 0.0515 0.0200 0.1140 4.85
6 Very Inverse 2.0000 0.4910 21.60 19.6100
7 Extremely Inverse 2.0000 0.1217 29.10 28.2000
8 Normally Inverse 8.9341 2.0938 9.00 0.17966
9 Short Time Inverse 0.2663 1.2969 0.50 0.03393
10 Long Time Inverse 5.6143 1.0000 15.75 2.18592
R
No.
Tripping
Characteristic
Formula for the
Reset
Characteristic
Formula for the Tripping
Characteristic
settable factor:
k = 0.05 ... 10.00
Characteristic
Constants
b c a
3 Operation
P631
P631/EN M/R-11-C // P631-310-650 3-133