Central Unit 3BSE018105R1

Central Unit 3BSE018105R1

Central Unit 3BSE018105R1

To allow closing of breakers between asynchronous networks a synchronizing function is provided. The breaker close command is issued at the optimum time when conditions across 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 bus and line is larger than an adjustable parameter. If the frequency difference is less than this threshold value the system is defined to have a parallel circuit and the synchrocheck function is used. The synchronizing function measures the difference between the U-Line and the UBus.

It operates and enables a closing command to the circuit breaker when the calculated closing angle is equal to the measured phase angle and the following conditions are simultaneously fulfilled:

• The voltages U-Line and U-Bus are higher than the set values for UHighBusSynch and UHighLineSynch of the base voltages GblBaseSelBus 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 and larger than the set value of FreqDiffMin. If the frequency is less than FreqDiffMin the synchrocheck is used and the value of FreqDiffMin must thus be identical to the value FreqDiffM resp FreqDiffA for synchrocheck function.