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Mounting and Commissioning
3.1 Mounting and Connections
Figure 3-1
Trip Circuit Monitoring
It must be noted that two binary inputs or one binary input and one substitute resistor R must be connected in
series. The pickup threshold of the binary inputs must therefore be substantially below half the rated control DC
voltage.
If two binary inputs are used for the trip circuit supervision, these binary inputs must be isolated, i.o.w. not be
communed with each other or with another binary input. Therefore, if necessary, galvanic isolation must be
ensured using external measures.
If one binary input is used, a bypass resitor R must be used (refer to the following figure). This resistor R is
connected in series with the second circuit breaker auxiliary contact (Aux2), to also allow the detection of a trip
circuit failure when the circuit breaker auxiliary contact 1 (Aux1) is open and the command relay has reset. The
value of this resitor must be such that in the circuit breaker open condition (therefore Aux1 is open and Aux2
is closed) the circuit breaker trip coil (TC) is no longer picked up and binary input (BI1) is still picked up if the
command relay contact is open.
Figure 3-2
182
Connection diagram (example) for setting group switching with binary inputs
Trip circuit supervision with one binary input — Example for trip circuit 1
SIPROTEC, 7VK61, Manual
C53000-G1176-C159-3, Release date 05.2009
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