Siemens 6MD85, Manual

Page: 525 / 1256

above the set threshold values has been detected, the circuit-breaker auxiliary contact criterion becomes
effective.
The function has also a setting in which dropout is only possible if both criteria detect in parallel the circuit
breaker (or the CB pole with the 1/3-pole circuit breaker) to be open (dropout with auxiliary contact and
current-flow criterion).
In the default setting, the internal starting signal is held (see
Figure 7-3 and Figure 7-7 ). This means that
dropout is controlled solely by the switch or the circuit-breaker auxiliary contact criterion. If dropout is also to
occur on the falling edge of the starting signal (that is, when the pickup signal has a falling edge or the protec-
tion function trips), holding of the start signal must be disabled.
[loanreg1-030211-01.tif, 4, en_US]
Figure 7-13 Pickup/Dropout of the Circuit-Breaker Failure Protection Function (3-Pole Circuit Breaker)
Protection and Automation Functions
7.1 Circuit-Breaker Failure Protection
SIPROTEC 5, High-Voltage Bay Controller, Manual 525
C53000-G5040-C015-9, Edition 11.2017