Siemens siprotec 7SA6, Manual

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Introduction
1-9
7SA6 Manual
C53000-G1176-C156-2
1.4 Scope of Functions
The numerical Distance Protection SIPROTEC
®
7SA6 has the following functions
(sometimes dependent on the order variant):
Distance Protection
•
Protection for all types of short-circuit in systems with earthed, resonant-earthed or
isolated star point;
•
Different pickup schemes enable the user to adapt the distance protection system
to different network conditions and user’s requirements:
overcurrent pickup, voltage and angular-controlled pickup or impedance starting
(with polygonal angle-dependent characteristeric) can be selected;
•
Reliable distinction between load and short-circuit conditions, also on long, heavily
loaded lines;
•
High sensitivity in the case of a weakly loaded system, extreme stability against
load jumps and power swings;
•
Optimum adaption to line conditions by means of a polygonal tripping characteristic
with separate setting along the X–axis (reach) and R–axis (arc resistance reserve),
separate R–setting for earth faults.
•
Six measuring systems for each distance zone (full scheme design);
•
Six distance zones, selectable as forward, reverse or non-directional reaching, one
may be graded as an overreaching zone;
•
Nine time stages for the distance zones;
•
Direction determination is done with unfaulted loop (quadrature) voltages and
voltage memory, thereby achieving unlimited directional sensitivity, and not
affected by capacitive voltage transformer transients;
•
Current transformer saturation detection and compensation;
•
Compensation against the influence of a parallel line;
•
Shortest tripping time is approx. 15 ms (f
N
= 60 Hz) or 17 ms (f
N
= 50 Hz);
•
Phase segregated tripping (in conjunction with single-pole or single- and three-pole
auto-reclosure);
•
Non-delayed tripping after switching on to a fault;
•
Two sets of zero sequence compensation factors.
Power Swing
Suppplement
(optional
for Impedance
Starting)
•
Power swing detection with dZ/dt–measurement with three measuring systems;
•
Power swing detection up to a maximum of 7 Hz swing frequency;
•
In service also during single-pole dead times ;
•
Settable power swing programs;
•
Prevention of undesired tripping by the distance protection during power swings;
•
Tripping for out-of-step conditions can also be configured.
Teleprotection
Supplement Can be configured to various schemes for:
•
Permissive Underreach Transfer Trip (PUTT) (directly via pickup or via overreach
zone that is set separately)