3.74
SEL-387-0, -5, -6 Relay
Instruction Manual
Date Code 20170601
Differential, Restricted Earth Fault, Thermal, and Overcurrent Elements
Time-Overcurrent Curves
Figure 3.35
IEC Class C Curve (Extremely Inverse): C3
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.5 .6 .7 .8 .9 1
.02
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.05
.09
.07
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.1
.2
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1
4
2
3
5
6 7 8 9
10
40
20
30
70
50
60
80
90 100
80
10
2
3
6
4
5
7
9
8
20
50
30
40
60
70
100
90
0.20
0.10
0.05
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
Time in Seconds
Multiples of Pickup
Time in Cycles 60 Hz (50Hz)
3 (2.5)
6 (5)
15 (12.5)
30 (25)
60 (50)
600 (500)
150 (125)
300 (250)
1500 (1250)
3000 (2500)
6000 (5000)
Summary of Contents for SEL-387-0
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