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