ABB DPU 1500R Instruction Book page 24

ABB Distribution Protection Unit 1500R
Timing Curves
Time Overcurrent Curve Equation
Table 1-12. Constants for IEC Time Overcurrent Characteristics
1-10
IEC
K
Trip Time =
α
G
– 1
G
b
Reset Time = instantaneous
G
= multiples of pickup current
G
b
Time multiple range 0.05 to 1.0 in steps of 0.05
Curve K
Extremely Inverse 80.0
Very Inverse 13.5
Inverse 0.14
Long Time Inverse 120.0
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x time multiple
α
2.0
1.0
0.02
1.0
9/99
Protective Functions