Section 12 Control12.1 Synchrocheck, energizing check, and synchronizingSESRSYN IP14558-1 v412.1.1 IdentificationM14889-1 v4Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberSynchrocheck, energizing check, andsynchronizingSESRSYNsc/vcSYMBOL-M V1 EN-US2512.1.2 Application IP15111-1 v112.1.2.1 Synchronizing SEMOD171992-5 v9To allow closing of breakers between asynchronous networks, a synchronizingfeature is provided. The breaker close command is issued at the optimum timewhen conditions across the breaker are satisfied in order to avoid stress on thenetwork and its components.The systems are defined as asynchronous when the frequency difference betweenbus and line is larger than an adjustable parameter. If the frequency difference isless than this threshold value the system is defined to have a parallel circuit and thesynchrocheck function is used.The synchronizing function measures the difference between the U-Line and the U-Bus. It operates and enables a closing command to the circuit breaker when thecalculated closing angle is equal to the measured phase angle and the followingconditions are simultaneously fulfilled:• The voltages U-Line and U-Bus are higher than the set values forUHighBusSynch and UHighLineSynch of the respective base voltagesGblBaseSelBus and GblBaseSelLine.• The difference in the voltage is smaller than the set value of UDiffSynch.• The difference in frequency is less than the set value of FreqDiffMax andlarger than the set value of FreqDiffMin. If the frequency is less thanFreqDiffMin the synchrocheck is used and the value of FreqDiffMin must thusbe identical to the value FreqDiffM resp FreqDiffA for synchrocheck function.1MRK 505 393-UEN B Section 12ControlLine differential protection RED650 2.2 IEC 215Application manual
