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Figure 2-30
Tripping logic for the 1st zone
7SA522 Manual
C53000-G1176-C155-3
In the case of zones Z1, Z2 and Z1B single-pole tripping is possible for single-phase
faults, if the device version includes the single-pole tripping option. Therefore the
event output in these cases is provided for each pole. Different trip delay times can be
set for single-phase and multiple-phase faults in these zones. For multiple-phase
faults and faults in the other zones, the tripping is always three pole.
Note
Binary input ´!S 7ULS 3HUPµ (FNo. 381) must be activated to achieve single-pole
tripping. The internal automatic reclosing function may also grant the single-pole per-
mission. The binary input is usually controlled by an external automatic reclosure
device.
The trip delay times of the zones (except for Z1 which is usually always set without
delay) can be bypassed. The grading times are started either via zone pickup or
general pickup of the distance protection function. The undelayed release results from
the line energisation logic, which may be externally initiated via the circuit breaker
close signal derived from the circuit breaker control switch or from an internal line en-
ergisation detection. Zones Z4 and Z5 may be blocked by external criteria (FNo. 3617
´!%/2&. =7ULSµ, FNo. 3618 ´!%/2&. =7ULSµ).
2.2 Distance protection
103
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