reclosing will take place when the phase angle difference is big and increasing. In this caseit should be safer to close when the phase angle difference is smaller.To fulfill the above requirements the synchronism check function is provided withduplicate settings, one for steady (Manual) conditions and one for operation underdisturbed conditions (Auto).SynchroCheckFuse failFuse failLine voltage LinereferencevoltageBus voltageV-Bus > 80 % of GblBaseSelBusV-Line > 80 % of GblBaseSelLineVDiffSC < 0.02 – 0.50 p.u.PhaseDiffM < 5 - 90 degreesPhaseDiffA < 5 - 90 degreesFreqDiffM < 3 - 1000 mHzFreqDiffA < 3 - 1000 mHzANSI10000195-2-en.vsdANSI10000195 V2 ENFigure 129: Principle for the synchronism check function11.1.2.3 Energizing checkThe main purpose of the energizing check function is to facilitate the controlled re-connection of disconnected lines and buses to energized lines and buses.The energizing check function measures the bus and line voltages and compares them toboth high and low threshold values. The output is given only when the actual measuredconditions match the set conditions. Figure 130 shows two substations, where one (1) isenergized and the other (2) is not energized. Power system 2 is energized (DLLB) fromsubstation 1 via the circuit breaker A.Section 11 1MRK 506 334-UUS AControl290Application manual
