Siemens siprotec 7SA6 User Manual page 26

High Current Fast
Switch-on-to-Fault
Protection
Sensitive Earth
Fault Detection
(optional)
Automatic
Reclosure
(optional)
Synchronism and
Voltage Check
(Dead-line /
Dead-bus Check)
(optional)
1-10
• Stub protection: additional stage for fast tripping of faults between the
current transformer and circuit breaker (when the isolator switching
status feed back is available); particularly suited to sub-stations with
1
1 / circuit breaker arrangements.
2
• Fast tripping for switch-on-to-fault conditions;
• Selectable for manual closure or following each closure of the circuit
breaker;
• With integrated line energization detection.
For resonant-earthed or isolated systems with
• Detection of displacement voltage
• Determination of earth-faulted phases
• Sensitive determination of the earth fault direction
• Phase displacement correction for current transformers
• For reclosure after single-pole, three-pole or single and three-pole
tripping;
• Single or multiple reclosure (up to 8 reclosure attempts);
• With separate action times for every reclosure attempt, optionally
without action times;
• With separate dead times after single-pole and three-pole tripping,
separate for the first four reclosure attempts;
• Controlled optionally by protection start with separate dead times after
single, two and three-pole starting
• Optionally with adaptive dead time, phase-to-phase voltage and
reduced dead time
• Checking synchronism conditions before reclosure after three-pole
switching;
• Fast measuring of voltage difference U diff of the phase angle
ϕ
difference diff and the frequency difference f diff;
• Alternative check of dead-line / dead-bus before reclosure;
• Switching under asynchronous network conditions with advance
calculation of the synchro-time possible;
• Adjustable minimum and maximum voltage;
• Checking synchronism or dead-line / dead-bus also before manual
closure of the circuit breaker, with separate limit values;
• Measurement via transformer also possible;
• Measuring voltages optionally phase-phase or phase-earth
7SA6 Manual
C53000-G1176-C133-1