Functions
2.43 Trip Circuit Supervision
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
297
Figure 2-138 Principle of trip circuit monitor with two binary inputs (connected to common potential)
Depending on the switching state of the trip relay and circuit breaker, the binary inputs are initiated (logic state
„H“ in the table below) or short circuited (logic state „L“).
Table 2-16 Condition Table for Binary Inputs, depending on RTC and CB Position
With this solution, it is impossible to distinguish between status 2 („normal operation with open CB“ and „RTC
has tripped with success“). However these two statuses are normal and thus not critical. Status 4 is only theo-
retical and indicates a hardware error. The state where both binary inputs are not energized („L“) is only present
during a short transition phase (trip relay contact is closed, but the circuit breaker has not yet opened) if the trip
circuit is healthy. A continuous state of this condition is only possible when the trip circuit has been interrupted,
a short-circuit exists in the trip circuit, battery voltage failure occurs, or malfunctions occur with the circuit
breaker mechanism. Accordingly it is used as monitoring criterion.
The conditions of the two binary inputs are scanned periodically. A query takes place about every 600 ms. If
three consecutive conditional checks detect an abnormality (after 1.8 s), an annunciation is reported (see
Figure 2-137). The repeated measurements help to determine the delay of the alarm message and to avoid
that an alarm is output during short-time transition periods. After the fault in the trip circuit has been eliminated,
the alarm is reset automatically after the same time.
No. Trip contact Circuit
breaker
Aux 1 Aux 2 BI 1 BI 2 dyn. status stat. status
1 Open TRIP Closed Open H L normal operation with closed CB
2 Open or Closed CLOSE Open Closed L H Normal operation with open CB or TR
has tripped with success
3 Closed TRIP Closed Open L L Transition/fault Fault
4 Open CLOSED or
OPEN
Closed Closed H H Theoretical status: AuxCont defec-
tive, BI defective, wrong connection
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