5-252 L30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUALCONTROL ELEMENTS CHAPTER 5: SETTINGS5The synchronism check function supervises the paralleling of two parts of a system that are to be joined by the closure ofa circuit breaker. The synchrocheck elements are typically used at locations where the two parts of the system areinterconnected through at least one other point in the system.Synchrocheck verifies that the voltages (V1 and V2) on the two sides of the supervised circuit breaker are within set limitsof magnitude, angle, and frequency differences. The time that the two voltages remain within the admissible angledifference is determined by the setting of the phase angle difference ΔΦ and the frequency difference ΔF (slip frequency). Itcan be defined as the time it takes the voltage phasor V1 or V2 to traverse an angle equal to 2 × ΔΦ at a frequency equalto the frequency difference ΔF. This time is calculated by:Eq. 5-27whereΔΦ is phase angle difference in degreesΔF is frequency difference in HzIf one or both sources are de-energized, the synchrocheck programming can allow for closing of the circuit breaker usingundervoltage control to bypass the synchrocheck measurements (dead source function).SYNCHK1 V1 SOURCE — This setting selects the source for voltage V1 (see the Notes section that follows).SYNCHK1 V2 SOURCE — Selects the source for voltage V2, which must not be the same as used for the V1 (see Notes). SYNCHK1 MAX FREQHYSTERESIS: 0.06 HzRange: 0.00 to 0.10 Hz in steps of 0.01 SYNCHK1 SYNC CLOSE:OffRange: FlexLogic operand SYNCHK1 S-CLS MAXdF: 0.50 HzRange: 0.10 to 2.00 Hz in steps of 0.01 SYNCHK1 S-CLS MINdF: 0.10 HzRange: 0.01 to 1.00 Hz in steps of 0.01 SYNCHK1 S-CLS BRKTIME: 0.035 sRange: 0.010 to 0.500 s in steps of 0.001 SYNCHK1 V2 MAG CORRFACTOR: 1.00Range: 0.10 to 10.00 in steps of 0.01 SYNCHK1 V2 ANGLESHIFT: 0Range: -180 to +180 degrees in steps of 1 SYNCHK1 DEAD SOURCESELECT: LV1 and DV2Range: None, LV1 and DV2, DV1 and LV2, DV1 or DV2,DV1 Xor DV2, DV1 and DV2 SYNCHK1 DEAD V1MAX VOLT: 0.30 puRange: 0.04 to 1.25 pu in steps of 0.01 SYNCHK1 DEAD V2MAX VOLT: 0.30 puRange: 0.04 to 1.25 pu in steps of 0.01 SYNCHK1 LIVE V1MIN VOLT: 0.70 puRange: 0.04 to 1.25 pu in steps of 0.01 SYNCHK1 LIVE V2MIN VOLT: 0.70 puRange: 0.04 to 1.25 pu in steps of 0.01 SYNCHK1 TARGET:Self-resetRange: Self-reset, Latched, Disabled SYNCHK1 EVENTS:DisabledRange: Disabled, Enabled
