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9/99
Timing Curves
Time Overcurrent Curve Equation
M = Multiples of pickup current (I/Ipu)
n = Time Dial setting
Table 1-11. Constants for ANSI Time Overcurrent Characteristics
Curve
Extremely Inverse
6.407
Very Inverse
2.855
Inverse
0.0086
Short Time Inverse
0.00172
Definite Time
1.281
Long Time Ext. Inv.
64.07
Long Time Very Inv.
28.55
Long Time Inverse
0.086
Recloser Curve #8
4.211
Notes:
•
The time in seconds for the Long Time Extremely Inverse Curve is 10 times that of the Extremely
Inverse Curve.
•
The time in seconds for the Long Time Very Inverse Curve is 10 times that of the Very Inverse Curve.
•
The time in seconds for the Long Time Inverse Curve is 10 times that of the Inverse Curve.
•
The ANSI curves comply with ANSI C37.112.
•
See Section 10 for information on optional Recloser curves.
Protective Functions
Trip Time = (
Reset Time = (
A
B
C
0.025
1
0.0712
1
0.0185
1
0.0037
1
0.005
1
0.250
1
0.712
1
0.185
1
0.013
0.35
ABB Distribution Protection Unit 1500R
ANSI
A
14n–5
+ B) x (
p
M
–C
9
D
14n–5
) x (
|1–EM|
9
P
D
2.0
3
2.0
1.346
0.02
0.46
0.02
0.092
2.0
0.6
2.0
30
2.0
13.46
0.02
4.6
1.8
3.29
website:www.abb.com/papd
)
)
E
K
0.998
80.0
2.0
0.998
13.5
1.0
0.998
0.14
0.02
0.998
0.998
0.998
0.998
0.998
120.0
1.0
1.5
a
1-9
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