GE 750 User Manual

GE Power Management 750/760 Feeder Management Relay 12-
3
12 S5 PROTECTION 12.1 TIME OVERCURRENT CURVE CHARACTERISTICS
12
12.1.3 ANSI CURVES
The ANSI time overcurrent curve shapes conform to industry standard curves and fit into the ANSI C37.90
curve classifications for extremely, very, normally, and moderately inverse. The 750/760 curves are derived
from the formula:
where T = Trip Time (seconds)
M = Multiplier Setpoint
I = Input Current
I
pu
= Pickup Current Setpoint
A, B, C, D, E = Constants
Table 12–3: ANSI CURVE TRIP TIMES (IN SECONDS)
Graphs of standard time-current curves on 11”
×
17” log-log graph paper are available upon request.
Requests may be placed with our literature department.
Table 12–2: ANSI CURVE CONSTANTS
ANSI CURVE CONSTANTS A B C D E
EXTREMELY INVERSE 0.0399 0.2294 0.5000 3.0094 0.7222
VERY INVERSE 0.0615 0.7989 0.3400 -0.2840 4.0505
NORMALLY INVERSE 0.0274 2.2614 0.3000 -4.1899 9.1272
MODERATELY INVERSE 0.1735 0.6791 0.8000 -0.0800 0.1271
()
()()
TM A
B
C
D
C
E
C
I
I
I
I
I
I
pu
pu pu
=× +
−
+
−
+
−










23
Multiplier Current (I / Ipu )
(M) 1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
ANSI EXTREMELY INVERSE
0.5 2.000 0.872 0.330 0.184 0.124 0.093 0.075 0.063 0.055 0.049
1.0 4.001 1.744 0.659 0.368 0.247 0.185 0.149 0.126 0.110 0.098
2.0 8.002 3.489 1.319 0.736 0.495 0.371 0.298 0.251 0.219 0.196
4.0 16.004 6.977 2.638 1.472 0.990 0.742 0.596 0.503 0.439 0.393
6.0 24.005 10.466 3.956 2.208 1.484 1.113 0.894 0.754 0.658 0.589
8.0 32.007 13.955 5.275 2.944 1.979 1.483 1.192 1.006 0.878 0.786
10.0 40.009 17.443 6.594 3.680 2.474 1.854 1.491 1.257 1.097 0.982
ANSI VERY INVERSE
0.5 1.567 0.663 0.268 0.171 0.130 0.108 0.094 0.085 0.078 0.073
1.0 3.134 1.325 0.537 0.341 0.260 0.216 0.189 0.170 0.156 0.146
2.0 6.268 2.650 1.074 0.682 0.520 0.432 0.378 0.340 0.312 0.291
4.0 12.537 5.301 2.148 1.365 1.040 0.864 0.755 0.680 0.625 0.583
6.0 18.805 7.951 3.221 2.047 1.559 1.297 1.133 1.020 0.937 0.874
8.0 25.073 10.602 4.295 2.730 2.079 1.729 1.510 1.360 1.250 1.165
10.0 31.341 13.252 5.369 3.412 2.599 2.161 1.888 1.700 1.562 1.457
ANSI NORMALLY INVERSE
0.5 2.142 0.883 0.377 0.256 0.203 0.172 0.151 0.135 0.123 0.113
1.0 4.284 1.766 0.754 0.513 0.407 0.344 0.302 0.270 0.246 0.226
2.0 8.568 3.531 1.508 1.025 0.814 0.689 0.604 0.541 0.492 0.452
4.0 17.137 7.062 3.016 2.051 1.627 1.378 1.208 1.082 0.983 0.904
6.0 25.705 10.594 4.524 3.076 2.441 2.067 1.812 1.622 1.475 1.356
8.0 34.274 14.125 6.031 4.102 3.254 2.756 2.415 2.163 1.967 1.808
10.0 42.842 17.656 7.539 5.127 4.068 3.445 3.019 2.704 2.458 2.260
ANSI MODERATELY INVERSE
0.5 0.675 0.379 0.239 0.191 0.166 0.151 0.141 0.133 0.128 0.123
1.0 1.351 0.757 0.478 0.382 0.332 0.302 0.281 0.267 0.255 0.247
2.0 2.702 1.515 0.955 0.764 0.665 0.604 0.563 0.533 0.511 0.493
4.0 5.404 3.030 1.910 1.527 1.329 1.208 1.126 1.066 1.021 0.986
6.0 8.106 4.544 2.866 2.291 1.994 1.812 1.689 1.600 1.532 1.479
8.0 10.807 6.059 3.821 3.054 2.659 2.416 2.252 2.133 2.043 1.972
10.0 13.509 7.574 4.776 3.818 3.324 3.020 2.815 2.666 2.554 2.465

GE 750 Specifications

General

Brand	GE
Model	750
Category	Relays
Language	English