Siemens 7SJ82, Manual

Page: 724 / 1638

i
i
NOTE
From V7.30 on, the value
VN measured
is no longer provided. If you have selected this value in earlier
versions, you can use either the following methods instead after upgrading the configuration to V7.30 or a
later version:
•
Select the value
V0 calculated
for the
Measured value
parameter in the function Overvoltage
protection with any voltage.
•
Use the function Overvoltage protection with zero-sequence voltage/residual voltage.
If the function Overvoltage protection with any voltage is used in a 1-phase function group, the param-
eter
Measured value
is not visible.
Parameter: Threshold
•
Default setting
(_:391:3) Threshold
=
110 V
Specify the
Threshold
(pickup threshold) for the specific application.
Depending on the measured value, the
Threshold
is set either as
Measured voltage
or as
Phase-to-
phase
quantity.
i
i
NOTE
If the function is used in a Voltage-current 1-phase function group connected to the 1-phase voltage
measuring point with the voltage type
VN broken-delta
, you set the threshold value based on the
equivalent zero-sequence voltage.
Calculate the equivalent zero-sequence voltage V
0 equiv. sec
from the measured voltage V
N sec
with the
following formula:
You can find more information about the
Matching ratio Vph / VN
parameter in chapter 6.1.6 Appli-
cation and Setting Notes for Measuring Point Voltage 3-Phase (V-3ph) .
Parameter: Operate delay
•
Default setting
(_:391:6) Operate delay
=
3 s
The
Operate delay
must be set for the specific application.
Parameter: Dropout ratio
•
Recommended setting value
(_:391:4) Dropout ratio
=
0.95
The recommended set value of
0.95
is appropriate for most applications. To achieve high measurement preci-
sion, the
Dropout ratio
can be reduced, to 0.98, for example.
Operation as Supervision Function
If you want the tripping 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.
Protection and Automation Functions
6.27 Overvoltage Protection with Any Voltage
724 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017