Siemens SIPROTEC 7VU681, User Manual

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Function
2.1 ATS
SIPROTEC, 7VU681, User Manual
C53000-G1176-C368-1, Release Date 07.2012
26
Figure 2-6 Primary Diagram of Transfer Mode Line2 -> Line1
The lower sides of the 2 transfers are called Lines. These 2 modes work in the condition that the circuit breaker
of one line is closed and working as the operating power supply. Both buses are supplied by it. When Bus
coupler circuit-breaker is closed, the circuit breaker of another line is open and working as standby power
supply. Once the operating power supply is lost and the two buses voltages are dead, ATS starts to trip the CB
of the operating line, and close the CB of the standby line after a time delay.