Scope Of Functions - Siemens siprotec 7SA6 User Manual

Introduction
1.4

Scope of Functions

Distance Protection
Power Swing
Suppplement
(optional
for Impedance
Starting)
Teleprotection
Supplement
1-8
The numerical Distance Protection SIPROTEC
(sometimes dependent on the order variant):
• 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
• Phase segregated tripping (in conjunction with single-pole or single- and three-pole
auto-reclosure);
• Non-delayed tripping after switching on to a fault.
• 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.
Can be configured to various schemes for:
• Permissive Underreach Transfer Trip (PUTT) (directly via pickup or via overreach
zone that is set separately)
®
7SA6 has the following functions
= 60 Hz) or 17 ms (f
N N
C53000-G1176-C133-1
= 50 Hz);
7SA6 Manual