ANDANDANDbus1VoltageORORORULN1FFULN1OKUB1FFUB1OKUB2FFUB2OKB2QCLDB2QOPENB1QCLDB1QOPENBLOCKbus2VoltageAND1 B2SELB1SELANDANDAND USELFAILen05000779-2.vsdORinvalidSelectionbusVoltageselectedFuseOKIEC05000779 V2 ENFigure 99: Logic diagram for the voltage selection function of a single circuit breaker with double busbars10.1.7.8 Voltage selection for a 1 1/2 circuit breaker arrangementNote that with 1½ breaker schemes three Synchrocheck functions must be used for thecomplete diameter. Below, the scheme for one Bus breaker and the Tie breaker isdescribed.This voltage selection function uses the binary inputs from the disconnectors andcircuit breakers auxiliary contacts to select the right voltage for the SESRSYN(Synchronism, Synchronizing and Energizing check) function. For the bus circuitbreaker one side of the circuit breaker is connected to the busbar and the other side isconnected either to line 1, line 2 or the other busbar depending on the best selection ofvoltage circuit.Inputs LN1QOPEN-LN1QCLD, B1QOPEN-B1QCLD, B2QOPEN-B2QCLD,LN2QOPEN-LN2QCLD are inputs for the position of the Line disconnectorsrespectively the Bus and Tie breakers. The outputs LN1SEL, LN2SEL and B2SELwill give indication of the selected Line voltage as a reference to the fixed Bus 1voltage, which indicates B1SEL.1MRK 511 287-UEN A Section 10Control221Technical manual
