5-48 F650 DIGITAL BAY CONTROLLER GEK-106310-AF
5.4 PROTECTION ELEMENTS CHAPTER 5: SETPOINTS
The instantaneous mode provides that, when the current value falls below the reset level, energy is immediately reset to 0.
This mode is used for coordinating with static devices, which behave in a similar way. In the Linear mode, energy is
reduced at a speed associated with the reset times curve (showed in the curve tables), trying to simulate the behavior of
electromechanical relays.
5.4.2.1 IEEE curves
This family of curves follows the standard IEEE C37.112-1996 for extremely inverse, very inverse, and inverse curves. The
following formulas define this type of curve:
Where:
t = Operation time in seconds
Dial = multiplier setting
I = Input current
Itap = Current pickup value
A, B, p = constants defined by the standard
T
RESET
= reset time in seconds
t
r
= characteristic constant.
Table 5-21: Constants for IEEE curves
Table 5-22: Tripping time in seconds for IEEE curves
IEEE Curve Shape Name A B p tr
IEEE Extremely Inverse IEEE Ext Inv 28.2 0.1217 2.0000 29.1
IEEE Very Inverse IEEE Very Inv 19.61 0.491 2.0000 21.6
IEEE Inverse IEEE Mod Inv 0.0515 0.1140 0.0200 4.85
Dial Current (I/Itap)
1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
IEEE Extremely Inverse
0.5 11.341 4.761 1.823 1.001 0.648 0.464 0.355 0.285 0.237 0.203
1.0 22.682 9.522 3.647 2.002 1.297 0.927 0.709 0.569 0.474 0.407
2.0 45.363 19.043 7.293 4.003 2.593 1.855 1.418 1.139 0.948 0.813
4.0 90.727 38.087 14.587 8.007 5.187 3.710 2.837 2.277 1.897 1.626
6.0 136.090 57.130 21.880 12.010 7.780 5.564 4.255 3.416 2.845 2.439
8.0 181.454 76.174 29.174 16.014 10.374 7.419 5.674 4.555 3.794 3.252
10.0 226.817 95.217 36.467 20.017 12.967 9.274 7.092 5.693 4.742 4.065
IEEE Very Inverse
0.5 8.090 3.514 1.471 0.899 0.654 0.526 0.450 0.401 0.368 0.345
1.0 16.179 7.028 2.942 1.798 1.308 1.051 0.900 0.802 0.736 0.689
2.0 32.358 14.055 5.885 3.597 2.616 2.103 1.799 1.605 1.472 1.378
4.0 64.716 28.111 11.769 7.193 5.232 4.205 3.598 3.209 2.945 2.756
6.0 97.074 42.166 17.654 10.790 7.849 6.308 5.397 4.814 4.417
4.134
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