Siemens siprotec 7SA522, User Manual

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Introduction
1-9
7SA522 Manual
C53000-G1176-C119-2
High Current Fast
Switch-on-to-Fault
Protection
•
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.
Automatic
reclosure
(optional)
•
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
Synchronism and
voltage check
(dead-line / dead-
bus check)
(optional)
•
checking synchronization conditions before reclosure after three-pole switching;
•
fast measuring of voltage difference U diff of the phase angle difference
ϕ
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;
•
check synchronism or dead-line / dead-bus also before manual closure of the circuit
breaker possible, with separate limit values;
•
measurement via transformer also possible;
•
measuring voltages optionally phase-phase or phase-earth
Overvoltage
Protection
(optional)
•
Overvoltage detection of each phase-earth voltage with common time delay;
•
separate measuring system with a separate time delay, for the zero sequence volt-
age, or any other single-phase voltage;
•
the reset ratio of the single-phase (zero sequence) voltage protection can be set;
•
command transfer to the remote line end is possible.
Fault Location
•
Initiated by trip command or reset of the fault detection;
•
computation of the distance to fault with dedicated measured value registers;
•
fault location output in ohm, kilometers or miles and % of line length;
•
parallel line compensation can be selected;
•
load compensation available.
Circuit breaker
failure protection
(optional)
•
with independent current stages for monitoring current flow through every pole of
the circuit breaker;
•
with independent monitoring time steps for single-pole and three-pole tripping;
•
start by trip command of every internal protection function;
•
start by external trip functions possible;