Section 12 Control12.1 Synchronism check, energizing check, andsynchronizing SESRSYN (25)12.1.1 IdentificationFunction description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberSynchrocheck, energizing check, andsynchronizingSESRSYNsc/vcSYMBOL-M V1 EN2512.1.2 Application12.1.2.1 SynchronizingTo allow closing of breakers between asynchronous networks a synchronizing function isprovided. The breaker close command is issued at the optimum time when conditionsacross the breaker are satisfied in order to avoid stress on the network and its components.The systems are defined to be asynchronous when the frequency difference between busand line is larger than an adjustable parameter. If the frequency difference is less than thisthreshold value the system is defined to have a parallel circuit and the synchronism checkfunction is used.The synchronizing function measures the difference between the V-Line and the V-Bus.It operates and enables a closing command to the circuit breaker when the calculatedclosing angle is equal to the measured phase angle and the following conditions aresimultaneously fulfilled:• The voltages V-Line and V-Bus are higher than the set values for VHighBusSynchand VHighLineSynch of the base voltages GblBaseSelBus and GblBaseSelLine.• The difference in the voltage is smaller than the set value of VDiffSynch.• The difference in frequency is less than the set value of FreqDiffMax and larger thanthe set value of FreqDiffMin. If the frequency is less than FreqDiffMin the1MRK 505 337-UUS - Section 12Control281Application manual
