Section 5 1MAC309294-MB FControl functions324 RER620Technical ManualThe energizing check function measures the bus and line voltages and compares them toboth high and low threshold detectors. The output is given only when the actual measuredquantities match the set conditions.The synch-check function in the continuous mode measures the conditions across thecircuit breaker from separate power system parts and compares them to the set limits.When all the measured quantities are within their set limits simultaneously, that is, thesystems are in synchronism, the output for allowing or executing the circuit breakerclosing is activated.The synch-check function in the command mode measures the conditions across the circuitbreaker and also determines the angle change occurring during the closing delay of thecircuit breaker from the measured slip frequency. The output is given only when all themeasured conditions are within their set limits simultaneously. The issue of the output istimed to give closure at the optimal delay of the circuit breaker and the closing circuit.5.3.4 Operation principleThe function can be enabled and disabled with the Operation setting. The correspondingparameter values are “On” and “Off”.The synch-check function has two parallel functionalities, the synch-check and energizingcheck functionality. The operation of the synchronism and energizing check function canbe described using a module diagram. All the modules in the diagram are explained in thenext sections.Figure 167: Functional module diagramThe synch-check function can operate either with V_AB or V_A voltages. The selectionof used voltages is defined with the VT connection setting of the line voltage generalparameters.
