A-2
Appendix
BE1-951
Table A-1. 51P, 51Q, and 51N Time Characteristic Curve Constants
Curve
Selection
BE Curve Name
Trip Characteristic Constants
N
N
I
I
Reset
A
B
C
N
K
R
S1
S, Short Inverse
0.2663
0.03393
1.000
1.2969
0.028
0.5000
S2
S2, Short Inverse
0.0286
0.02080
1.000
0.9844
0.028
0.0940
L1
L1, Long Inverse
5.6143
2.18592
1.000
1.000
0.028
15.750
L2
L2, Long Inverse
2.3955
0.00000
1.000
0.3125
0.028
7.8001
D
D, Definite Time
0.4797
0.21359
1.000
1.5625
0.028
0.8750
M
M, Moderately Inverse
0.3022
0.12840
1.000
0.5000
0.028
1.7500
I1
I, Inverse Time
8.9341
0.17966
1.000
2.0938
0.028
9.0000
I2
Inverse Time
0.2747
0.10426
1.000
0.4375
0.028
0.8868
V1
V, Very Inverse
5.4678
0.10814
1.000
2.0469
0.028
5.5000
V2
V2, Very Inverse
4.4309
0.09910
1.000
1.9531
0.028
5.8231
E1
Extremely Inverse
7.7624
0.02758
1.000
2.0938
0.028
7.7500
E2
E2, Extremely Inverse
4.9883
0.01290
1.000
2.0469
0.028
4.7742
A
Standard Inverse
0.01414
0.00000
1.000
0.0200
0.028
2.0000
B
B, Very Inverse (I
2
t)
1.4636
0.00000
1.000
1.0469
0.028
3.2500
C
Extremely Inverse (I
2
t)
8.2506
0.00000
1.000
2.0469
0.028
8.0000
G
Long Time Inverse (I
2
t)
12.1212
0.00000
1.000
1.0000
0.028
29.0000
F
Fixed Time
N
0.0000
1.00000
1.000
0.0000
0.028
1.0000
46
Neg. Sequence
Overcurrent
1.0
0
0
2
0.028
100
P
Programmable
0 to 600
0 to 25
0 to 1
0.5 to 2.5
0.028
0 to 30
N
Curve F has a fixed delay of one second times the Time Dial setting.
I
For integrated reset, append R to the curve name. For example, curve S1 has instantaneous
reset. Curve S1R has integrated reset.
TIME-OVERCURRENT CHARACTERISTIC CURVE GRAPHS
Figures A-1 through A-17 illustrate the characteristic curves of the BE1-951 relay. Table A-2 cross-
references each curve to existing electromechanical relay characteristics. Equivalent time dial settings were
calculated at a value of five times pickup. A drawing number is provided in the caption of each graph.
Contact the Basler Electric Power Systems Group Customer Service Department at (618) 654-2341 and
request the drawing number to order a full-size (10 inches by 12 inches) Characteristic Curve graph on
transparent paper (vellum). A complete set of drawings is available by requesting Basler Publication
9 2520 00 990.