Siemens siprotec 7SA6 User Manual

Functions
6-1077SA6 Manual
C53000-G1176-C133-1
Figure 6-64 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 6-65). The
stabilization factor (=slope) may be changed by means of the parameter ,SK67$%
6ORSH(setting address , Subsection 6.5.2). It applies to all stages.
Figure 6-65 Phase current stabilization

3I0p InrushBlk
<HV
1R
≥1
&
&
inrush
stabilization
direction
determination
Reverse
&
&

<HV
1R
,S627)7ULS

<HV
1R
,S7HOHS%,
permissive
teleprot.
switch on
to fault
≥1
EF 3I0p TRIP
EF 3I0p Pickup
T0
 627)7LPH'(/$<
&
PICKUP
PICKUP+DIRECT.

&
627)2S0RGH
3I
0
3I
0
>

,S3,&.83
t
3U
0
T0
 8LQYPLQLPXP
 7UHY8LQY
T0
 7IRUZ8LQY
 Op. mode 3I0p
Reverse
Forward
Non-Directional
„1“
Inactive
3U
0
3U
0
>
 8!8LQY
≥1
>EF Inst TRIP.
FNr 1309
FNr 1357
FNr 1369
FNr 1310
Forward
!()7HOH%/
&
&
3I
0
I
N
I
Phmax
I
N
blocking of the
pick up
,!
Slope:
,SK67$%6ORSH

Siemens siprotec 7SA6 Specifications

General

Brand	Siemens
Model	siprotec 7SA6
Category	Relays
Language	English