Siemens 6MD85, Manual

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Voltage-transformer connection phase-to-ground: V
act-sec
< 58.7 V
Voltage-transformer connection phase-to-phase: V
act-sec
< 58.7 V ⋅√3 = 101.6 V
•
Check the overcurrent blocking.
i
i
NOTE
The overcurrent blocking works with the maximum current of all phases, for this reason, check the phases
A, B, and C separately.
Example
Parameters Value
Power system →
CT 3-phase
:
Rated primary current
I
CT-prim
7500 A
Power system →
CT 3-phase
:
Rated secondary current
I
CT-sec
1 A
Voltage cont. 2w →
General
:
Rated current
I
rated
5500 A
[fo_ibs_overcur_block, 1, en_US]
If you set the parameter
I> Threshold
to
150 %
, this results in an infeed current secondary of I
act-sec
> 1.1 A
for the example.
Line Compensation
•
Check the Z Compensation.
The parameter
Target voltage rising
represents the voltage drop across the line as a % at rated load. In
case of a voltage drop primary of 504 V across the line at rated current, according to the setting notes in
6.9.4.4 Line Compensation , this results in a setting value of 4.8 %.
The secondary current to be fed in at a load current for the 100 % load case results in:
[fo_ibs_load_current, 1, en_US]
where:
I
CT-prim
Power system →
CT 3-phase
:
Rated primary current
I
CT-sec
Power system →
CT 3-phase
:
Rated secondary current
I
rated
Voltage cont. 2w →
General
:
Rated current
The secondary voltage to be fed in for the 100 % load case with a control deviation D [%] to be tested for the
voltage-transformer connection phase-to-ground results in:
[fo_ibs_sec_volt, 1, en_US]
For the voltage-transformer connection phase-to-phase, the reference must be multiplied with the factor √3.
For a control deviation of D = 0 % to be tested and a setting value
Target voltage rising
of
4.8 %
, in
the example, for voltage-transformer connection phase-to-ground, this results in a secondary infeed voltage
of:
Functional Tests
10.10 Commissioning Hints for Voltage Control
SIPROTEC 5, High-Voltage Bay Controller, Manual 1081
C53000-G5040-C015-9, Edition 11.2017