5-182 T60 Transformer Protection System GE Multilin5.6 GROUPED ELEMENTS 5 SETTINGS5IEEE CURVES:The IEEE time overcurrent curve shapes conform to industry standards and the IEEE C37.112-1996 curve classificationsfor extremely, very, and moderately inverse. The IEEE curves are derived from the formulae:, (EQ 5.29)where: T = operate time (in seconds), TDM = Multiplier setting, I = input current, I pickup = Pickup Current settingA, B, p = constants, TRESET = reset time in seconds (assuming energy capacity is 100% and RESET is “Timed”),tr = characteristic constantTable 5–16: IEEE INVERSE TIME CURVE CONSTANTSIEEE CURVE SHAPE A B P TRIEEE Extremely Inverse 28.2 0.1217 2.0000 29.1IEEE Very Inverse 19.61 0.491 2.0000 21.6IEEE Moderately Inverse 0.0515 0.1140 0.02000 4.85Table 5–17: IEEE CURVE TRIP TIMES (IN SECONDS)MULTIPLIER(TDM)CURRENT ( I / I pickup)1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0IEEE EXTREMELY INVERSE0.5 11.341 4.761 1.823 1.001 0.648 0.464 0.355 0.285 0.237 0.2031.0 22.682 9.522 3.647 2.002 1.297 0.927 0.709 0.569 0.474 0.4072.0 45.363 19.043 7.293 4.003 2.593 1.855 1.418 1.139 0.948 0.8134.0 90.727 38.087 14.587 8.007 5.187 3.710 2.837 2.277 1.897 1.6266.0 136.090 57.130 21.880 12.010 7.780 5.564 4.255 3.416 2.845 2.4398.0 181.454 76.174 29.174 16.014 10.374 7.419 5.674 4.555 3.794 3.25210.0 226.817 95.217 36.467 20.017 12.967 9.274 7.092 5.693 4.742 4.065IEEE VERY INVERSE0.5 8.090 3.514 1.471 0.899 0.654 0.526 0.450 0.401 0.368 0.3451.0 16.179 7.028 2.942 1.798 1.308 1.051 0.900 0.802 0.736 0.6892.0 32.358 14.055 5.885 3.597 2.616 2.103 1.799 1.605 1.472 1.3784.0 64.716 28.111 11.769 7.193 5.232 4.205 3.598 3.209 2.945 2.7566.0 97.074 42.166 17.654 10.790 7.849 6.308 5.397 4.814 4.417 4.1348.0 129.432 56.221 23.538 14.387 10.465 8.410 7.196 6.418 5.889 5.51310.0 161.790 70.277 29.423 17.983 13.081 10.513 8.995 8.023 7.361 6.891IEEE MODERATELY INVERSE0.5 3.220 1.902 1.216 0.973 0.844 0.763 0.706 0.663 0.630 0.6031.0 6.439 3.803 2.432 1.946 1.688 1.526 1.412 1.327 1.260 1.2072.0 12.878 7.606 4.864 3.892 3.377 3.051 2.823 2.653 2.521 2.4144.0 25.756 15.213 9.729 7.783 6.753 6.102 5.647 5.307 5.041 4.8276.0 38.634 22.819 14.593 11.675 10.130 9.153 8.470 7.960 7.562 7.2418.0 51.512 30.426 19.458 15.567 13.507 12.204 11.294 10.614 10.083 9.65410.0 64.390 38.032 24.322 19.458 16.883 15.255 14.117 13.267 12.604 12.068T TDMAII pickup---------------- p1–---------------------------------- B+×= T RESET TDMt r1 II pickup---------------- 2–------------------------------------×=
