Toshiba GR-200-5 Instruction Manual

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6F2T0207 (0.01)GRE200 (5,6)- 44 -where:t = operating time for constant current I (seconds),I = energizing current (amperes),Is = earth fault current setting (amperes),TMS = time multiplier setting,k, α, c = constants defining curve.The nine pre-programmed standard characteristic curve are defined in Table 2.2-1. Inaddition, one original (user-programmable) curve can be applied. One curve can be chosen foreach EF stage. Figure 2.2-3 illustrates these characteristic curves. For example, the usershould set one for the scheme switches [EF1-Timer]. (That is, “IEC-NI” is for IEC NormalInverse, “IEC-VI” for IEC Very Inverse, “IEC-EI” for IEC Extremely Inverse, “UK-LTI” for UKLong Time Inverse, “IEEE-MI “ for IEEE Moderately Inverse, “IEEE-VI” for IEEE Very Inverse,“IEEE-EI” for IEEE Extremely Inverse, “US-CO2” for US CO2 short time inverse, “US-CO8” forUS CO8 inverse, and “Original” for user-programmable characteristic.)In the IDMT operation, the user can also program the characteristic using time-multiplier-setting (TMS) for the required operate time. For example, the IEC characteristic isselected, the user can set the TMS value using the setting [EF1-TMS-IEC] (incidentally, thedefault value of the TMS is 1.00). The other TMSs are also available by the [EF1-TMS-UK],[EF1-TMS-IEEE], [EF1-TMS-US] and [EF1-TMS-ORG].Table 2.2-1 Constants for IDMTCurve type(IEC 60255-151) Curve Description k α cA IEC Normal Inverse (IEC-NI) 0.14 0.02 0B IEC Very Inverse (IEC-VI) 13.5 1 0C IEC Extremely Inverse (IEC-EI) 80 2 0- UK Long Time Inverse (UK-LTI) 120 1 0D IEEE Moderately Inverse (IEEE-MI) 0.0515 0.02 0.114E IEEE Very Inverse (IEEE-VI) 19.61 2 0.491F IEEE Extremely Inverse (IEEE-EI) 28.2 2 0.1217- US CO8 inverse (US-CO8) 5.95 2 0.18- US CO2 short time inverse (US-CO2) 0.02394 0.02 0.01694