2.7 Earth fault overcurrent protection in earthed systems (optional)
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7SA522 Manual
C53000-G1176-C155-3
sure to prevent signal race conditions. It is issued as fault indication ´()%/2&.µ
(FNo 1332).
If the device is combined with an external automatic reclose device or if single-pole
tripping can result from a separate (parallel tripping) protection device, the earth fault
protection must be blocked via binary input during the single-pole open condition.
Switching onto an
Earth Fault
The line energisation detection can be used to achieve quick tripping when energising
the circuit breaker in case of an earth fault. The earth fault protection can then trip
three-pole without delay. Parameters can be set to determine for which stage(s) the
non-delayed tripping following energization apply (see also logic diagrams from Figure
2-63 to Figure 2-65).
The non-delayed tripping in case of line energization detection is blocked as long as
the inrush-stabilization recognizes a rush current. This prevents instantaneous trip-
ping by a stage which, under normal conditions, is sufficiently delayed during energi-
zation of a transformer.
2.7.2 Setting Notes
General During the configuration of the device scope of functions (refer to Section 2.1.1,
address (DUWK)DXOW2&) it was determined which group of characteristics
are to be available. Only those parameters that apply to the available characteristics,
according to the selected configuration and the version of the device, are accessible
in the procedures described below.
Parameter )&7(DUWK)OW2& can be used to switch the earth fault protection
21 or 2)). This refers to all functions of the earth fault protection.
If not required, each of the four stages can be deactivated by setting its 02'( to
,QDFWLYH (see below).
Blocking The earth fault protection can be blocked by the distance protection to give preference
to the selective fault clearance by the distance protection over tripping by the earth
fault protection. In setting address %/2&.IRU'LVW it is determined whether
blocking is done during each fault detection of the distance protection (HYHU\
3,&.83) or only during single-phase fault detection by the distance protection
(SKDVH3,&.83) or only during multiple-phase fault detection by the distance pro-
tection (PXOWLSK3,&.83). If blocking is not desired, set 12.
It is also possible to block the earth-fault protection trip only for pickup of the distance
protection on the protected line section. To block the earth fault protection for faults
occurring within zone Z1, set address %/.IRU'LV=RQH to LQ]RQH=. To
block the earth fault protection for faults occurring within zone Z1 or Z1B, set address
%/.IRU'LV=RQH to LQ]RQH==%. If, however, blocking of the earth
fault protection by the distance protection is to take effect regardless of the fault loca-
tion, set address %/.IRU'LV=RQH to LQHDFK]RQH.
Address thus refers to the fault type
and address to the fault location. The
two blocking options create an AND condition. To block the earth fault protection only
for single-phase faults occurring within zone Z1, set address %/2&.IRU
'LVW = SKDVH3,&.83 and %/.IRU'LV=RQH = LQ]RQH=. To block
the earth fault protection for any fault type (any distance protection pickup) occurring
within zone Z1, the setting %/2&.IRU'LVW = HYHU\3,&.83 and
%/.IRU'LV=RQH = LQ]RQH= applies.
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