ANDANDANDbus1VoltageORORORVL1FFVL1OKVB1FFVB1OKVB2FFVB2OKBUS2_CLBUS2_OPBUS1_CLBUS1_OPselectedFuseOKBLOCKbus2VoltagebusVoltageAND invalidSelectionB2SELB1SELANDANDAND VSELFAILen05000779_ansi.vsdORNOTANSI05000779 V1 ENFigure 151: Logic diagram for the voltage selection function of a single circuit breaker with double busbars12.1.7.8 Voltage selection for a breaker-and-a-half circuit breaker arrangementNote that with breaker-and-a-half schemes two Synchronism check functions must beused in the IED (three for two IEDs in a complete bay). Below, the scheme for one Busbreaker and the Tie breaker is described.This voltage selection function uses the binary inputs from the disconnectors andcircuit breakers auxiliary contacts to select the right voltage for the SESRSYN(Synchronism and Energizing check) function. For the bus circuit breaker one side ofthe circuit breaker is connected to the busbar and the other side is connected either toline 1, line 2 or the other busbar depending on the arrangement.Inputs LINE1_OP-LINE1_CL, BUS1_OP-BUS1_CL, BUS2_OP-BUS2_CL,LINE2_OP-LINE2_CL are inputs for the position of the Line disconnectorsrespectively the Bus and Tie breakers. The outputs L1SEL, L2SEL and B2SEL willgive indication of the selected Line voltage as a reference to the fixed Bus 1 voltage,which indicates B1SEL.1MRK 502 043-UUS B Section 12Control329Technical Manual
