Functions
6-1257SA6 Manual
C53000-G1176-C156-2
ping with this stage it is, however, a prerequisite that the time of the voltage-controlled
stage has already expired (without directional check). In case the zero voltage is too
low or the voltage transformer circuit-breaker is tripped, this stage is also disabled.
The function of the zero sequence voltage time protection can be blocked by the dis-
tance protection. This gives the selective fault detection, carried out by the distance
protection with preference over the tripping by the zero sequence voltage time protec-
tion.
The zero sequence voltage time protection can also be blocked during a single-pole
auto-reclosure cycle. This prevents from false measurement caused by the zero-se-
quence values then appearing.
If the device operates with external automatic reclosure or if single-pole tripping is pos-
sible via a different protection (operating in parallel), the zero sequence voltage time
protection must be blocked during the single-pole open condition via a binary input.
Figure 6-72 Directional zero voltage time protection with non-directional back-up stage
Phase Current
Stabilization
Non-symmetrical load conditions in multiple-earthed systems or different current
transformer errors can result in a zero sequence current. This zero sequence current
could cause faulty pick-up of the earth current stages if low pick-up thresholds are set.
To avoid this, the earth current stages are stabilized by the phase current: As the
phase currents increase, the pick up thresholds are increased (Figure 6-73). The sta-
bilization factor (=slope) may be changed by means of the parameter
Iph-STAB.
Slope
(setting address 3104, Subsection 6.7.2). It applies to all stages.
3150
3I0p InrushBlk
Yes
No
≥1
&
&
inrush
stabilization
direction
determination
Reverse
&
&
3149
Yes
No
3I0p SOTF-Trip
3148
Yes
No
3I0p Telep/BI
permissive
teleprot.
switch on
to fault
≥1
EF 3I0p TRIP
EF 3I0p Pickup
T0
3173
SOTF Time DELAY
&
PICKUP
PICKUP+DIRECT.
3172
&
SOTF Op. Mode
3I
0
3I
0
>
3141
3I0p PICKUP
t
3U
0
T0
3183 U0inv. minimum
3185 T rev. (U0inv)
T0
3184 T forw. (U0inv)
3140
Op. mode 3I0p
Reverse
Forward
Non-Directional
„1“
Inactive
3U
0
3U
0
>
3182 3U0>(U0 inv)
≥1
>EF Inst TRIP.
FNr 1309
FNr 1357
FNr 1369
FNr 1310
Forward
>EF Tele BL
&
&
To Next Page
Loading...
Need help?
General