![Siemens SIPROTEC 7SD80 Manual Download Page 158](http://html.mh-extra.com/html/siemens/siprotec-7sd80/siprotec-7sd80_manual_382671158.webp)
Functions
2.12 Circuit-Breaker Test
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
158
2.12.2
Circuit-Breaker Position Detection
For Protection Purposes
Different protection and supplementary functions need information about the circuit-breaker status in order to
operate optimally. This is helpful for
• the circuit-breaker failure protection (refer to Section 2.6),
• the verification of the dropout condition for the trip command (see Section „Terminating the Trip Command“).
A circuit-breaker position logic is incorporated in the device (Figure ). Depending on the type of auxiliary con-
tact(s) provided by the circuit breaker and the method in which these are connected to the device, there are
several alternatives of implementing this logic.
In most cases, it is sufficient to send the status of the circuit breaker from the CB's auxiliary contacts over a
binary input to the device. The NO auxiliary contact of the circuit breaker is connected to a binary input which
must be routed to
„>52a 3p Closed“
(no. 379).
If the series connection of the poles' auxiliary NC contacts is available, the corresponding binary input is routed
to
„>52b 3p Open“
(no. 380).
The output signals of the circuit-breaker position logic can be processed by the individual protection and sup-
plementary functions. The output signals are blocked if the signals transmitted from the circuit breaker are not
plausible: for example, the circuit breaker cannot be open and closed at the same time.
The evaluation of the measured quantities is according to the local conditions of the measuring points (see
Section 2.1.6.1 at margin heading „Circuit-Breaker Status“).
The phase currents are available as measured quantities. A flowing current excludes that the circuit breaker is
open (exception: a short circuit between current transformer and circuit breaker). If the circuit breaker is closed,
it may, however, still occur that no current is flowing. The decisive setting for the evaluation of the measured
quantities is
PoleOpenCurrent
(address
1130
) for the presence of the currents.
In 7SD80 the position of the circuit-breaker poles detected by a device is also transmitted to the remote end
device. Thus the circuit-breaker positions at both ends are known.
Figure 2-62
Circuit-breaker position logic