Siemens SIPROTEC 7ST6, Руководство пользователя, Страница: 170 / 356

2 Functions
170
7ST6 Manual
E50417-G1176-C251-A3
2.17 Trip Circuit Supervision
2.17.1 Functional Description
Trip Circuit Super-
vision The overhead contact line protection 7ST6 is equipped with an integrated trip circuit
supervision. Depending on the number of available binary inputs (not connected to a
common potential), monitoring with one or two binary inputs can be selected. If the al-
location of the required binary inputs does not match the selected monitoring mode, a
corresponding alarm is issued („TripC1 ProgFAIL“). 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.
Supervision with
Two Binary Inputs When using two binary inputs, these are connected according to Figure 2-49, 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
Ctrl
> 2 U
BImin
). Since at least 19 V are needed for each binary input,
the monitor can only be used with a system control voltage of over 38 V.
Figure 2-49 Principle of trip circuit monitoring with two binary inputs
Monitoring with two binary inputs not only detects interruptions in the trip circuit and
loss of control voltage, it also monitors the response of the circuit breaker using the
position of the circuit breaker auxiliary contacts.
Depending on the conditions of the trip contact and the circuit breaker, the binary
inputs are activated (logical condition „H“ in the following table), or short-circuited
(logical condition „L“).
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