4-36 489 Generator Management Relay GE Multilin4.7 S6 VOLTAGE ELEMENTS 4 SETPOINTS4Volts/Hertz is calculated per unit as follows:4.7.4 PHASE REVERSALPATH: SETPOINTS ÖØ S6 VOLTAGE ELEMENTS ÖØ PHASE REVERSALThe 489 can detect the phase rotation of the three phase voltages. A trip will occur within 200 ms if the Phase Reversal fea-ture is turned on, the generator is offline, each of the phase-phase voltages is greater than 50% of the generator ratedphase-phase voltage and the phase rotation is not the same as the setpoint. Loss of VT fuses cannot be detected when thegenerator is offline and could lead to maloperation of this element. If the VT type is selected as "None", the phase reversalprotection is disabled.The formula for Volts/Hertz Curve 2 is:where: T = trip time in secondsD = VOLTS/HERTZ TRIP DELAY setpointV = RMS measurement of VabF = frequency of VabVNOM = generator voltage setpointFS = generator frequency setpointPickup = VOLTS/HERTZ TRIP PICKUP setpointThe V/Hz Curve 2 trip curves are shown on the rightfor delay settings of 0.1, 0.3, 1, 3, and 10 seconds.The formula for Volts/Hertz Curve 3 is:where: T = trip time in secondsD = VOLTS/HERTZ TRIP DELAY setpointV = RMS measurement of VabF = frequency of VabVNOM = generator voltage setpointFS = generator frequency setpointPickup = VOLTS/HERTZ TRIP PICKUP setpointThe V/Hz Curve 3 trip curves are shown on the rightfor delay settings of 0.1, 0.3, 1, 3, and 10 seconds. PHASE REVERSAL [ENTER] for morePHASE REVERSALTRIP: OffRange: Off, Latched, UnlatchedASSIGN TRIPRELAYS (1-4): 1---Range: Any combination of Relays 1 to 4T DV F⁄V nom F s⁄( ) Pickup×----------------------------------------------------- 1–--------------------------------------------------------------= , when VF---- Pickup>808743A1-X2.CDR0.111010010001.00 1.20 1.40 1.60 1.80 2.00Multiples of Volts/Hertz Pickup10310.3TIME DELAY SETTING0.1Time to Trip (seconds)T DV F⁄V nom F s⁄( ) Pickup×-----------------------------------------------------⎝ ⎠⎛ ⎞ 0.5 1–--------------------------------------------------------------------------= , when VF---- Pickup>808743A1-X3.CDR0.11101001000100001.00 1.20 1.40 1.60 1.80 2.00Multiples of Voltz/Hertz Pickup10310.3TIME DELAY SETTING0.1Time to Trip (seconds)NOTEVolts/Hertz phase-phase voltage rated phase-phase voltage⁄frequency rated frequency⁄----------------------------------------------------------------------------------------------------------------------------------=ENTERESCAPEð ðMESSAGEESCAPE
