Siemens SIPROTEC Manual page 235

The parameters 3116, 3126, 3136 and 3157 are used to define which stage is to be blocked during the single-
pole dead time. If the corresponding stage is to be blocked, the setting YES remains unchanged. If not, set No
(non-dir.).
Note
Stages of the earth fault protection, which are not to be blocked during the single-pole dead time, will not be
blocked even if the earth fault protection itself gives a single-pole trip command. Pickup and trip command of
the earth fault protection can thus only drop out if the earth current caused by the load current lies below the
threshold value of such a stage.
The earth fault protection can also be blocked by the differential protection. The parameter 3175 EF BLK
Dif.PU can be used to activate (setting value YES) or deactivate (setting value NO) this blocking. For the du-
ration of blocking the earth-fault protection trip the message 1335 „EF TRIP BLOCK" is reported as ON.
Trip
When setting the power system data (Section 2.1.2.1), it was specified whether single-pole tripping is set for
all stages of the earth fault protection together or separately.
When setting 238 EarthFltO/C 1p to stages together, parameter 3109 Trip 1pole E/F becomes
visible; the parameters for phase-selective settings are hidden.
Address 3109 Trip 1pole E/F specifies that the earth fault protection trips single-pole, provided that the
faulted phase can be determined with certainty. This address is only valid for devices that have the option to
trip single-pole. If you are using single-pole automatic reclosure, the setting YES (default setting) remains valid.
Otherwise set NO.
When setting stages separat., the parameters for the phase-selective setting are visible (3117 Trip 1p
3I0>>>, 3127 Trip 1p 3I0>>, 3137 Trip 1p 3I0> and 3158 Trip 1p 3I0p) parameter 3109 Trip
1pole E/F is hidden.
The parameters 3117, 3127, 3137 and 3158 can be used to determine which stage is to trip 1-pole, provided
that the faulted phase can be determined with certainty. If the corresponding stage is to trip 1-pole, the setting
YES remains unchanged; if not, set NO.
Definite time stages
First of all, the mode for each stage is set: address 3110 Op. mode 3I0>>>, address 3120 Op. mode 3I0>>
and address 3130 Op. mode 3I0>. Each stage can be set to operate Forward (usually towards line),
Reverse (usually towards busbar) or Non-Directional (in both directions). If a single stage is not required,
set its mode to Inactive.
The definite time stages 3I0>>> (address 3111), 3I0>> (address 3121) and 3I0> (address 3131) can be
used for a three-stage definite time overcurrent protection. They can also be combined with the inverse time
stage 3I0p PICKUP (address 3141, see below). The pick up thresholds should in general be selected such
that the most sensitive stage picks up with the smallest expected earth fault current.
The 3I >> and 3I
0
abridged filter with shorter response time. Whereas, the stages 3I
earth fault detection due to their effective method of suppressing harmonics.
If no inverse time stage, but rather a fourth definite time stage is required, the „inverse time" stage can be im-
plemented as a definite time stage. This must already be taken regard of during the configuration of the pro-
tection functions (refer to Section 2.1.1.3, address 131 Earth Fault O/C = Definite Time). For this
stage, the address 3141 3I0p PICKUP then determines the current pickup threshold and address 3147
Add.T-DELAY the definite time delay.
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
>>> stages are best suited for fast tripping stages (instantaneous), as these stages use an
0
2.8 Earth Fault Protection in Earthed Systems (optional)
> and 3I are best suited for very sensitive
0 0P
Functions
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