5-154 N60 Network Stability and Synchrophasor Measurement System GE Multilin5.7 CONTROL ELEMENTS 5 SETTINGS5If one or both sources are de-energized, the synchrocheck programming can allow for closing of the circuit breaker usingundervoltage control to by-pass the synchrocheck measurements (dead source function).• SYNCHK1 V1 SOURCE: This setting selects the source for voltage V1 (see NOTES below).• SYNCHK1 V2 SOURCE: This setting selects the source for voltage V2, which must not be the same as used for theV1 (see NOTES below).• SYNCHK1 MAX VOLT DIFF: This setting selects the maximum primary voltage difference in volts between the twosources. A primary voltage magnitude difference between the two input voltages below this value is within the permis-sible limit for synchronism.• SYNCHK1 MAX ANGLE DIFF: This setting selects the maximum angular difference in degrees between the twosources. An angular difference between the two input voltage phasors below this value is within the permissible limitfor synchronism.• SYNCHK1 MAX FREQ DIFF: This setting selects the maximum frequency difference in ‘Hz’ between the two sources.A frequency difference between the two input voltage systems below this value is within the permissible limit for syn-chronism.• SYNCHK1 MAX FREQ HYSTERESIS: This setting specifies the required hysteresis for the maximum frequency differ-ence condition. The condition becomes satisfied when the frequency difference becomes lower than SYNCHK1 MAXFREQ DIFF. Once the Synchrocheck element has operated, the frequency difference must increase above the SYNCHK1MAX FREQ DIFF + SYNCHK1 MAX FREQ HYSTERESIS sum to drop out (assuming the other two conditions, voltage andangle, remain satisfied).• SYNCHK1 DEAD SOURCE SELECT: This setting selects the combination of dead and live sources that will by-passsynchronism check function and permit the breaker to be closed when one or both of the two voltages (V1 or/and V2)are below the maximum voltage threshold. A dead or live source is declared by monitoring the voltage level. Sixoptions are available:None: Dead Source function is disabledLV1 and DV2: Live V1 and Dead V2DV1 and LV2: Dead V1 and Live V2DV1 or DV2: Dead V1 or Dead V2DV1 Xor DV2: Dead V1 exclusive-or Dead V2 (one source is Dead and the other is Live)DV1 and DV2: Dead V1 and Dead V2• SYNCHK1 DEAD V1 MAX VOLT: This setting establishes a maximum voltage magnitude for V1 in 1 ‘pu’. Below thismagnitude, the V1 voltage input used for synchrocheck will be considered “Dead” or de-energized.• SYNCHK1 DEAD V2 MAX VOLT: This setting establishes a maximum voltage magnitude for V2 in ‘pu’. Below thismagnitude, the V2 voltage input used for synchrocheck will be considered “Dead” or de-energized.• SYNCHK1 LIVE V1 MIN VOLT: This setting establishes a minimum voltage magnitude for V1 in ‘pu’. Above this mag-nitude, the V1 voltage input used for synchrocheck will be considered “Live” or energized.• SYNCHK1 LIVE V2 MIN VOLT: This setting establishes a minimum voltage magnitude for V2 in ‘pu’. Above this mag-nitude, the V2 voltage input used for synchrocheck will be considered “Live” or energized.NOTES ON THE SYNCHROCHECK FUNCTION:1. The selected sources for synchrocheck inputs V1 and V2 (which must not be the same source) may include both athree-phase and an auxiliary voltage. The relay will automatically select the specific voltages to be used by the syn-chrocheck element in accordance with the following table.NO. V1 OR V2(SOURCE Y)V2 OR V1(SOURCE Z)AUTO-SELECTEDCOMBINATIONAUTO-SELECTED VOLTAGESOURCE Y SOURCE Z1 Phase VTs andAuxiliary VTPhase VTs andAuxiliary VTPhase Phase VAB2 Phase VTs andAuxiliary VTPhase VT Phase Phase VAB3 Phase VT Phase VT Phase Phase VAB
