Siemens 7SJ85 - Settings

Parameter Value Description
no
The protection stage is not blocked.
Parameter: Current-flow criterion
•
Recommended setting value (_:2311:104) Current-flow criterion = on
Depending on the system, the voltage transformers are arranged on either the supply side or the junction side.
These 2 possible voltage transformer locations induce a different behavior of the function after tripping and
opening of the circuit breaker:
•
If they are located on the supply side, the voltage still exists.
•
If they are located on the junction side, the voltage does not exist.
Parameter Value Description
on
If the voltage transformers are located on the junction side, you can use the
current-flow criterion to make the pickup drops out when the current falls
below a minimum value (parameter Threshold I>).
off
In the case of undervoltage, the pickup of the undervoltage protection
stage persists when the current-flow criterion is not used.
Parameter: Threshold I>
•
Recommended setting value (_:2311:101) Threshold I> = 0.05 A
The Threshold I> parameter makes it possible to detect when the circuit breaker is closed. Siemens recom-
mends setting the Threshold I> parameter to 5% of the rated current. With a secondary rated transformer
current of 1 A, the secondary setting value for Threshold I> would be 0.05 A.
If the sensitivity of the Threshold I> parameter is set too high, compensation processes in the secondary
circuit of the current transformer extend the dropout time when breaking extremely high currents. To speed
up dropout, increase the default setting.
Operation as Supervision Function
If you want the stage to have a reporting effect only, generation of the operate indication and fault logging
can be disabled via the Operate & flt.rec. blocked parameter.
Settings
Addr.
Parameter C Setting Options Default Setting
General
_:2311:104 General:Current-flow
criterion
•
off
•
on
on
_:2311:101 General:Threshold I> 1 A @ 100 Irated 0.030 A to 10.000 A 0.050 A
5 A @ 100 Irated 0.15 A to 50.00 A 0.25 A
1 A @ 50 Irated 0.030 A to 10.000 A 0.050 A
5 A @ 50 Irated 0.15 A to 50.00 A 0.25 A
1 A @ 1.6 Irated 0.001 A to 1.600 A 0.050 A
5 A @ 1.6 Irated 0.005 A to 8.000 A 0.250 A
Definite-T 1
_:421:1 Definite-T 1:Mode
•
off
•
on
•
test
off
_:421:2 Definite-T 1:Operate &
flt.rec. blocked
•
no
•
yes
no
_:421:10 Definite-T 1:Blk. by
meas.-volt. failure
•
no
•
yes
yes
6.29.3.3
Protection and Automation Functions
6.29 Undervoltage Protection with 3-Phase Voltage
740 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017