Siemens siprotec 7SA522 User Manual page 285

Switching on to a
Dead Fault
Fault Detection and
Trip Logic
7SA522 Manual
C53000-G1176-C119-2
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Figure 6-80 Logic diagram of the stub protection
To achieve fast tripping following manual closure of the circuit breaker onto a dead
fault, the switch onto fault signal can be routed to the overcurrent protection. The over-
current protection can then trip three-pole without delay or with a reduced delay. It can
be determined via setting parameter for which stage(s) the rapid tripping following
closure on to a dead fault applies. (Refer also to the logic diagrams in Figure 6-77,
6-78 and 6-80, and Sub-section 6.1.3, margin "Circuit Breaker Status").
The fault detection signals of the individual phases (and earth) and the individual stag-
es are combined in such a manner that both the phase information as well as the stage
information of the picked up stages can be output. (Table 6-4).
In the case of the trip signals, the stage which resulted in the trip command is also in-
dicated. If the device has the option to trip single-pole, and this option has been acti-
vated, the pole which has been tripped is also indicated during single-pole tripping (re-
fer also to Sub-section 6.17.4 Overall Tripping Logic of the Device).
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I-STUB Pickup L1
I-STUB Pickup L2
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I-STUB Trip L1
I-STUB Pickup E
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I-STUB Trip E
Functions
I-STUB Pickup L3
I-STUB Trip L2
I-STUB Trip L3
6-137