ABB RELION 670 Series Technical Manual page 768

Section 14
Control
• The line 1 voltage is selected if the line 1 disconnector is closed.
• The bus 1 voltage is selected if the line 1 disconnector is open and the bus 1 circuit breaker is
closed.
• The line 2 voltage is selected if the line 2 disconnector is closed.
• The bus 2 voltage is selected if the line 2 disconnector is open and the bus 2 circuit breaker is
closed.
The function also checks the fuse-failure signals for bus 1, bus 2, line 1 and line 2. If a VT failure is
detected in the selected voltage an output signal VSELFAIL is set. This output signal is true if the
selected bus or line voltages have a MCB trip. This output as well as the function can be blocked
with the input signal BLOCK. The function block diagram for the voltage selection of a bus circuit
breaker is shown in figure
LINE1_OP
LINE1_CL
BUS1_OP
BUS1_CL
LINE2_OP
LINE2_CL
BUS2_OP
BUS2_CL
VB1OK
VB1FF
VB2OK
VB2FF
VL1OK
VL1FF
VL2OK
VL2FF
BLOCK
ANSI05000780 V2 EN-US
Figure 405: Simplified logic diagram for the voltage selection function for a bus circuit breaker in a breaker-
and-a-half arrangement
762
405 and for the tie circuit breaker in figure 406.
AND
AND
AND
AND
AND
AND
line2Voltage
bus2Voltage
OR
OR
OR
OR
OR
AND
line1Voltage
OR
AND
AND
AND
1MRK 502 066-UUS B
L1SEL
L2SEL
B2SEL
invalidSelection
lineVoltage
selectedFuseOK
AND
VSELFAIL
AND
en05000780_2_ansi.vsd
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