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2.24.2
Trip Circuit Supervision
The 7SD5 line protection is equipped with an integrated trip circuit supervision. Depending on the number of
available binary inputs (not connected to a common potential), supervision with one or two binary inputs can
be selected. If the routing of the required binary inputs does not comply with the selected monitoring mode, an
alarm is given („TripC1 ProgFAIL ...", with identification of the non-compliant circuit). When using two binary
inputs, malfunctions in the trip circuit can be detected under all circuit breaker conditions. When only one binary
input is used, malfunctions in the circuit breaker itself cannot be detected. If single-pole tripping is possible, a
separate trip circuit monitoring can be implemented for each circuit breaker pole provided that the required
binary inputs are available.
2.24.2.1 Functional Description
Supervision with Two Binary Inputs
When using two binary inputs, these are connected according to Figure 2-214 parallel to the associated trip
contact on one side, and parallel to the circuit breaker auxiliary contacts on the other.
A precondition for the use of the trip circuit supervision is that the control voltage for the circuit breaker is higher
than the total of the minimum voltages drops at the two binary inputs (U
needed for each binary input, the supervision function can only be used with a system control voltage of over
38 V.
Figure 2-214
TR
CB
TC
Aux1
Aux2
U-CTR
U-BI1
U-BI2
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
Principle of the trip circuit supervision with two binary inputs
Trip relay contact
Circuit breaker
Circuit breaker trip coil
Circuit breaker auxiliary contact (NO contact)
Circuit breaker auxiliary contact (NC contact)
Control voltage (trip voltage)
Input voltage of 1st binary input
Input voltage of 2nd binary input
2.24 Monitoring Functions
> 2·U
). Since at least 19 V are
Ctrl
BImin
Functions
439
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