Setting Notes - Siemens siprotec 7SD5 User Manual

diff). Another way of blocking the zone is to set a binary input (No 3610 „>BLOCK
Z1-Trip").
Switching onto a If the circuit breaker is manually closed onto a short circuit, the distance protection can
Fault issue an instantaneous trip command. By setting parameters it may be determined
which zone(s) is/are released following a manual close (refer to Figure 2-39). The line
energization information (input „SOTF") is derived from the state recognition.
Figure 2-39
Note
When switching onto a three-pole fault with the MHO characteristic, there will be no
voltage in the memory or unfaulted loop voltage available. To ensure fault clearance
when switching onto three-pole close-up faults, please make sure that in conjunction
with the configured MHO characteristic the instantaneous tripping function is always
enabled.
2.5.1.4

Setting Notes

At address 1501 FCT Distance the distance protection function can be switched ON
or OFF.
The minimum current for fault detection Minimum Iph> (address 1502) in case of
Minimum Current
impedance pickup is set somewhat (approx. 10 %) below the minimum short-circuit
current that may occur. For the other pickup modes it is set at address 1911.
In systems with earthed starpoint, the setting 3I0> Threshold (address 1503) is
Earth Fault
Detection set somewhat below the minimum expected earth fault current. 3I
sum of the phase currents |I
of current transformers. In non-earthed systems the setting value is recommended to
be below the earth current value for double earth faults.
7SD5 Manual
C53000-G1176-C169-1
Switching onto a fault
+ I + I
L1 L2 L3
2.5 Distance Protection
|, which equals the starpoint current of the set
is defined as the
0
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