Siemens siprotec 7SA6 User Manual

Functions
6-58 7SA6 Manual
C53000-G1176-C133-1
Figure 6-32 Directional characteristic with quadrature or memorized voltages
Pick-up and
Assignment to the
Polygons
Using the fault detection modes I, U/I or U/I/ϕ according to Subsection 6.2.2 the
impedances, that were calculated from the valid loops, are assigned, after the pick-up,
to the zone characteristics set for the distance protection. To avoid unstable signals at
the boundaries of a polygon, the characteristics have a hysteresis of approximately
5 % i.e. as soon as it has been determined that the fault impedance lies within a
polygon, the boundaries are increased by 5 % in all directions. The loop information is
also converted to faulted phase indication
Using the impedance pick-up the loop impedances calculated according to Subsection
6.2.3 are also assigned to the zone characteristics set for the distance protection, but
without a query of an explicite fault detection scheme. The pick-up range of the
distance protection is determined from the thresholds of the largest-set polygon taking
into consideration the respective direction. Here the loop information is also converted
into faulted phase indication.
“Pick-up” signals are also generated for each zone and converted into phase
information, e.g. 'LV3LFNXS/ = for zone Z1 and phase L1. This means that
each phase and each zone is provided with separate pick-up information. The
information is then processed in the zone logic (see Subsection 6.2.5) and by
additional functions (e.g. signal transmission logic, Subsection 6.4.1).
The loop information is also converted to phase indications. Further conditions for the
“pick-up” of a zone are that the direction must be in accordance with the configured
direction for the zone and that the zone is not blocked by the power swing blocking
(see Subsection 6.3.1). Furthermore the distance protection system must not be
switched off totally or blocked. Figure 6-33 shows the conditions mentioned.
F
2
F
1
E
1
E
2
Z
S1
Z
S2
Z
L
7SA6
“forward”
“reverse”
R
jX
I
2
I
1
F
1
Z
L
+ Z
S2
“forward”
“reverse”
R
jX
F
2
Z
S1
Z
L
+ Z
S2
6-32a
6-32c6-32b
Z
S1

Siemens siprotec 7SA6 Specifications

General

Brand	Siemens
Model	siprotec 7SA6
Category	Relays
Language	English