Siemens siprotec 7SD5

1 Introduction
30
7SD5 Manual
C53000-G1176-C169-1
Transmission of In-
formation
• Transmission of the measured values from all ends of the protected object with the
amount and phase
• Transmission of up to 4 fast commands to all remote ends (order option)
• Transmission of up to 24 additional binary signals to all remote ends (order option)
Time Overcurrent
Protection
• Selectable as emergency function during a failure of the main protection function(s)
due to a failure of the data communication and/or the measuring voltages, or as
backup function;
• Maximally two definite time stages (DT) and one inverse time stage (IDMT), each
for phase currents and for earth currents
• For inverse-time overcurrent protection a selection from various characteristics
based on several standards is possible
• Blocking capability, e.g. for reverse interlocking with any element
• Instantaneous tripping by any stage when switching onto a fault
• Stub fault protection: fast tripping of faults between the current transformer and line
isolator (when the isolator switching status feed back is available); particularly
suited to substations with 1
1
/
2
circuit breaker arrangements
Instantaneous
High-Current
Switch-onto-Fault
Protection
• Fast tripping for all faults on 100 % line length
• Selectable for manual closure or following each closure of the circuit breaker
• With integrated line energization detection
Automatic Reclo-
sure Function
(optional)
• For reclosure after single-pole, three-pole or single-pole 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
• With the option of an adaptive dead time: in this case only one device controls the
automatic reclosure cycles whilst at the other end(s) the automatic reclosure solely
depends on the one controlling device. The criteria used are voltage measurement
and/or the transmitted CLOSE command (Remote-CLOSE).
• Controlled optionally by protection pickup with separate dead times after single,
two-pole and three-pole pickup
• Optionally with adaptive dead time, reduced dead time and dead line check
Synchronism and
Voltage Check (op-
tional)
• Verification of the synchronous conditions before reclosing after three-pole tripping
• Fast measuring of voltage difference U
Diff
of the phase angle difference ϕ
Diff
and fre-
quency difference f
Diff
• Alternatively, check of the de-energized state before reclosing
• Closing at asynchronous system conditions with prediction of the synchronization
time
• Settable minimum and maximum voltage
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