frequencies must also be within a range of ±5 Hz from the rated frequency. Whenthe synchronizing option is included also for autoreclose there is no reason tohave different frequency setting for the manual and automatic reclosing and thefrequency difference values for synchronism check should be kept low.• The frequency rate of change is less than set value for both U-Bus and U-Line.• The difference in the phase angle is smaller than the set value of CloseAngleMax.• The closing angle is decided by the calculation of slip frequency and required pre-closing time.The synchronizing function compensates for the measured slip frequency as well asthe circuit breaker closing delay. The phase angle advance is calculated continuously.The calculation of the operation pulse sent in advance is using the measuredSlipFrequency and the set tBreaker time. To prevent incorrect closing pulses, amaximum closing angle between bus and line is set with CloseAngleMax. Table 51below shows the maximum settable value for tBreaker when CloseAngleMax is set to15 or 30 degrees, at different allowed slip frequencies for synchronizing. To minimizethe moment stress when synchronizing near a power station, a narrower limit for theCloseAngleMax needs to be used.Table 51:Dependencies between tBreaker and SlipFrequency with different CloseAngleMaxvaluestBreaker [s] (max settable value)withCloseAngleMax = 15degrees [default value]tBreaker [s] (max settable value)withCloseAngleMax = 30 degrees[max value]SlipFrequency [Hz](BusFrequency -LineFrequency)0.040 0.080 1.0000.050 0.100 0.8000.080 0.160 0.5000.200 0.400 0.2000.400 0.810 0.1001.000 0.0800.800 0.0501.000 0.040The reference voltage can be phase-neutral L1, L2, L3 or phase-phase L1-L2, L2-L3,L3-L1 or positive sequence (Require a three phase voltage, that is UL1, UL2 andUL3) . By setting the phases used for SESRSYN, with the settings SelPhaseBus1,SelPhaseBus2, SelPhaseLine2 and SelPhaseLine2, a compensation is madeautomatically for the voltage amplitude difference and the phase angle differencecaused if different setting values are selected for the two sides of the breaker. If neededan additional phase angle adjustment can be done for selected line voltage with thePhaseShift setting.15.1.2.2 SynchrocheckThe main purpose of the synchrocheck function is to provide control over the closingof circuit breakers in power networks in order to prevent closing if conditions forSection 15 1MRK 502 071-UEN -Control480 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062Application manual
