Functions
2.10 Monitoring Functions
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012
178
2.10.2 Trip Circuit Supervision 74TC
The 7SK80 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
allocation of the required binary inputs does not match the selected supervision type, a message to this effect
is generated („74TC ProgFail“).
Applications
• When using two binary inputs, malfunctions in the trip circuit can be detected under all circuit breaker con-
ditions.
• When only one binary input is used, malfunctions in the circuit breaker itself cannot be detected.
Prerequisites
A requirement for the use of trip circuit supervision is that the control voltage for the circuit breaker is at least
twice the voltage drop across the binary input (V
ct
> 2 · V
BImin
).
Since at least 19 V are needed for the binary input, the monitor can only be used with a system control voltage
of over 38 V.
2.10.2.1 Description
Supervision with Two Binary Inputs
When using two binary inputs, these are connected according to Figure 2-55, parallel to the associated trip
contact on one side, and parallel to the circuit breaker auxiliary contacts on the other.
Figure 2-55 Principle of the trip circuit supervision with two binary inputs
To Next Page
Loading...
