CHAPTER 5: SETTINGS GROUPED ELEMENTSL90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 5-2415FlexCurvesFlexCurves are described in the FlexCurves section later in this chapter. The curve shapes for the FlexCurves are derivedfrom the formulae:Eq. 5-19Eq. 5-20whereT = operate time (in seconds)TDM = Multiplier settingI = Input CurrentIpickup = Pickup Current settingTRESET = Reset Time in seconds (assuming energy capacity is 100% and RESET: Timed)Definite time curveThe Definite Time curve shape operates as soon as the pickup level is exceeded for a specified period of time. The basedefinite time curve delay is in seconds. The curve multiplier of 0.00 to 600.00 makes this delay adjustable frominstantaneous to 600.00 seconds in steps of 10 ms. The definite time curve shapes are defined as follows:Eq. 5-21Eq. 5-22whereT = Operate Time (in seconds)TDM = Multiplier settingI = Input CurrentIpickup = Pickup Current settingTRESET = Reset Time in seconds (assuming energy capacity is 100% and RESET: Timed)Recloser curvesThe L90 uses the FlexCurve feature to facilitate programming of 41 recloser curves. See the FlexCurves settings sectionearlier in this chapter for details.5.7.8.3 Phase time overcurrent (ANSI 51P, IEC PTOC)SETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) PHASE CURRENT PHASE TOC1(4) PHASE TOC 1 PHASE TOC1FUNCTION: DisabledRange: Disabled, Enabled PHASE TOC1 SIGNALSOURCE: SRC 1Range: SRC 1, SRC 2, SRC 3, SRC 4 PHASE TOC1INPUT: PhasorRange: Phasor, RMS PHASE TOC1PICKUP: 1.000 puRange: 0.020 to 30.000 pu in steps of 0.001 PHASE TOC1CURVE: IEEE Mod InvRange: see Overcurrent Curve Types table
