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Functions
2.8 Earth Fault Protection in Earthed Systems (optional)
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
234
2.8.2 Setting Notes
General
During the configuration of the device scope of functions (refer to Section 2.1.1, address 131 Earth Fault
O/C ) it was determined which group of characteristics is to be available. Only those parameters that apply to
the available characteristics, according to the selected configuration and the version of the device, are acces-
sible in the procedures described below.
Parameter 3101 FCT EarthFltO/C can be used to switch the earth fault protection ON or OFF . This refers to
all stages of the earth fault protection.
If not required, each of the four stages can be deactivated by setting its MODE... to Inactive (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 address
3102 BLOCK for
Dist. it is determined whether blocking is performed during each fault detection of the distance protection
( every PICKUP ) or only during single-phase fault detection by the distance protection ( 1phase PICKUP ) or
only during multiple-phase fault detection by the distance protection ( multiph. PICKUP ). If blocking is not
desired, set NO .
It is also possible to block the earth fault protection trip only for pickup of the distance protection on the protect-
ed line section. To block the earth fault protection for faults occurring within zone Z1, set address
3174 BLK
for DisZone to in zone Z1 . To block the earth fault protection for faults occurring within zone Z1 or Z1B,
set address 3174 BLK for DisZone to in zone Z1/Z1B . If, however, blocking of the earth fault protection
by the distance protection is to take effect regardless of the fault location, set address 3174 BLK for
DisZone to in each zone .
Address 3102 thus refers to the fault type and address 3174 to the fault location. The two blocking options
create an AND condition. To block the earth fault protection only for single-phase faults occurring in zone Z1,
set address
3102 BLOCK for Dist. = 1phase PICKUP and 3174 BLK for DisZone = in zone Z1 . To
block the earth fault protection for any fault type (any distance protection pickup) occurring within zone Z1, the
setting
3102 BLOCK for Dist. = every PICKUP and 3174 BLK for DisZone = in zone Z1 applies.
The earth fault protection must be blocked during single-pole automatic reclose dead time to avoid pickup with
the zero-sequence values and, if applicable, the negative sequence values arising during this state.
When setting the power system data (Section 2.1.2.1), it was specified whether all stages of the earth fault pro-
tection are blocked together or separately during the single-pole dead time.
When setting 238 EarthFltO/C 1p to stages together , parameter 3103 BLOCK 1pDeadTim becomes
visible; the parameters for phase-selective blocking are hidden.
Parameter 3103 BLOCK 1pDeadTim must be set to YES (presetting for devices with single-pole tripping) if a
single-pole automatic reclosure is to be performed. If not, set NO .
Setting parameter 3103 BLOCK 1pDeadTim to YES completely blocks the earth fault protection if the Open
Pole Detector has recognized a single-pole dead time. If no single-pole tripping is carried out in the protected
network, this parameter should be set to
NO .
Regardless of how parameter address 3103 BLOCK 1pDeadTim is set, the earth fault protection will always
be blocked during the single-pole dead time, if it has issued a trip command itself. This is necessary because
otherwise the picked up earth fault protection cannot drop out if the fault current was caused by load current.
When setting stages separat. , the parameters for phase-selective blocking become visible ( 3116 BLK
/1p 3I0>>> , 3126 BLK /1p 3I0>> , 3136 BLK /1p 3I0> and 3157 BLK /1p 3I0p ), parameter 3103
BLOCK 1pDeadTim is hidden.