Instructional Literature
Page
150
Effective: May 2008
Instructions for the FP-6000 Protective Relay
For more information visit: www.eaton.com
IB02602004E
Table 39. Constants for Inverse Time Overcurrent Curves.
1
FP-6000 does not directly provide IEC-D, IEC-E, and IEC-F curves. In the latest IEC standard, IEC-D, IEC-E and IEC-F are the same as ANSI Moderately Inverse, Very
Inverse, and Extremely Inverse, respectively.
8.3.3 Curve Shapes
The FP-6000 Protective Relay provides circuit breakers with an
extensive degree of selective coordination potential, and permits
curve shaping over a wide range. The available pickup settings,
which are inverse time overcurrent time multiplier settings, and
inverse time overcurrent (phase and ground) curve selections are
addressed with respect to their effect on the resultant
characteristic curve described above. The operating
characteristics of the relay are graphically represented by time-
current characteristic curves shown in Figure 45.
Figure 45. FP-6000 Time-Current Characteristic Curves.
CALCULATED CURVES
CURVE TYPE
P
A
B
T
r
ANSI/IEEE
Moderately Inverse
0.02
0.0515
0.114
4.85
Very Inverse
2
19.61
0.491
21.6
Extremely Inverse
2
28.2
0.1217
29.1
IEC
1
IEC-A
0.02
0.14
0
0.14
IEC-B
1
13.5
0
13.5
IEC-C
2
80
0
80
