GE Multilin G60 Generator Management Relay 5-1515 SETTINGS 5.6 CONTROL ELEMENTS55.6.5 OVERFREQUENCYPATH: SETTINGS !" CONTROL ELEMENTS !" OVERFREQUENCY ! OVERFREQUENCY 1(4)There are four overfrequency elements, numbered 1 through 4.A frequency calculation for a given source is made on the input of a voltage or current channel, depending on which isavailable. The channels are searched for the signal input in the following order: voltage channel A, auxiliary voltage chan-nel, current channel A, ground current channel. The first available signal is used for frequency calculation.The steady-state frequency of a power system is an indicator of the existing balance between the generated power and theload. Whenever this balance is disrupted through the disconnection of significant load or the isolation of a part of the sys-tem that has a surplus of generation, the effect will be an increase in frequency. If the control systems of the generators donot respond fast enough, to quickly ramp the turbine speed back to normal, the overspeed can lead to the turbine trip. Theoverfrequency element can be used to control the turbine frequency ramp down at a generating location. This element canalso be used for feeder reclosing as part of the "after load shedding restoration".The OVERFREQ 1 SOURCE setting selects the source for the signal to be measured. The OVERFREQ 1 PICKUP setting selectsthe level at which the overfrequency element is to pickup.Figure 5ñ98: OVERFREQUENCY SCHEME LOGIC# OVERFREQUENCY 1#OVERFREQ 1 FUNCTION:DisabledRange: Disabled, EnabledMESSAGE OVERFREQ 1 BLOCK:OffRange: FlexLogicô operandMESSAGE OVERFREQ 1 SOURCE:SRC 1Range: SRC 1, SRC 2, SRC 3, SRC 4MESSAGE OVERFREQ 1 PICKUP:60.50 HzRange: 20.00 to 65.00 Hz in steps of 0.01MESSAGE OVERFREQ 1 PICKUPDELAY: 0.500 sRange: 0.000 to 65.535 s in steps of 0.001MESSAGE OVERFREQ 1 RESETDELAY : 0.500 sRange: 0.000 to 65.535 s in steps of 0.001MESSAGE OVERFREQ 1 TARGET:Self-resetRange: Self-reset, Latched, DisabledMESSAGE OVERFREQ 1 EVENTS:DisabledRange: Disabled, Enabled827832A3.CDRFLEXLOGIC OPERANDSOVERFREQ 1 FUNCTION:OVERFREQ 1 BLOCK:OVERFREQ 1 SOURCE:OVERFREQ 1 PICKUP :OVERFREQ 1 DPOOVERFREQ 1 OPOVERFREQ 1 PKPRUNANDSETTINGSETTINGOVERFREQ 1 RESETDELAY :OVERFREQ 1 PICKUPDELAY :SETTINGEnabled=1Disabled=0tPKPt RSTSETTINGSETTINGOffSRC1Frequencyf PICKUP <
