Siemens siprotec 7SA6 User Manual

Functions
6-280 7SA6 Manual
C53000-G1176-C156-2
automatically removed. Definite time overcurrent emergency operation is possible
during the voltage failure if the overcurrent protection was configured accordingly (re-
fer to Section 6.11).
Additional
Measured Voltage
Failure Monitoring
If no measuring voltage is available after power-on of the device (e.g. because the
voltage transformers are not connected), the absence of the voltage can be detected
and reported by an additional monitoring function. Where circuit breaker auxiliary con-
tacts are used, they should be used for monitoring as well. Figure 6-143 shows the
logic diagram of the measured voltage failure monitoring.
A failure of the measured voltage is detected if:
• all three phase-to-earth voltages are smaller than FFM U<max (3ph),
• at least one phase current is greater than PoleOpenCurrent or at least one CB
pole is closed (selectable),
• no protection function has picked up,
• this condition persists for a settable time T V-Supervision (default setting:
3sec).
This time
T V-Supervision is required to prevent that a voltage failure is detected be-
fore the protection picks up.
If a failure is detected by anyone of these criteria, the annunciation
168 “Fail U ab-
sent
” is output, and the device switches to emergency operation (see Section 6.11).
Figure 6-143 Logic diagram of the additional measured voltage failure monitoring
Emerg. Func.
FailUabsent
FNr 168
I
L1
I
L1
>
I
L2
I
L3
T0
&
U
L3-E
I
L2
>
I
L3
>
U
L1-E
U
L2-E
Relay PICKUP
≥ 1
&
≥ 1
T V-Supervision
2916A
“1”
≥ 1
&
U<
U<
U<
≥ 1
V-Supervision
2915
off
with curr. supervis. ad CBaux
with curr. supervis.
FFM U<max (3ph) 2913A
PoleOpenCurrent 1130A
from CB position logic
(see Figure 6-151)
any pole closed

Siemens siprotec 7SA6 Specifications

General

Brand	Siemens
Model	siprotec 7SA6
Category	Relays
Language	English