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Control Functions
6.9 Voltage Controller
X
k
B
p
B
k
V
rated
With the parameter Reactive I control factor, you can adjust the control deviation D
circulating reactive current caused by a tap difference results in exceeding the control bandwidth. A Reac-
tive I control factor set too high can affect the control stability. In most cases, control quality and
control stability are assured with the default setting of 1.
The sum of the control deviation resulting from voltage deviation D
the circulating reactive current, results in:
D
= D
+ D
k
CRCk
V
and is compared with the set bandwidth. The following 2 diagrams show the summations of the control devia-
tion at negative and positive voltage deviation. A possible control deviation is caused by the circulating reac-
tive current. The circulating reactive current on transformer T
both voltage controllers in a different total deviation.
Negative voltage deviation -D
Changing to higher tap of T
For the calculation of the voltage deviation, the voltages of all voltage controllers are transferred with GOOSE
as a measured value and an average value is calculated. The voltage can be monitored. If the data are not
plausible, the voltage controller is blocked after a settable time delay.
Error Behavior
If the value of the circulating reactive current exceeds the threshold value Circul. current threshold
for a longer time than the set time delay Circul. current time delay, the indication
current blocking is issued and the voltage control blocked.
If the circulating reactive current value drops below the preset value, the signal is automatically reset. You can
achieve this by manually controlling the tap changer.
Blocking the Tap Changer in Case of a Fault
To activate the supervision functions in Follower mode, if the transformer differential protection is used, you
must set the parameter Blocking to Auto-Manual in the Voltage controller function.
474
Reactance of the transformer
Total susceptance (total susceptance value) of all parallel transformers (sum of the reciprocals
of the transformer reactance)
Susceptance of the transformer (reciprocal of the reactance)
Rated voltage of the transformer
V
with D
+ D
2
V
CRC2
and the control deviation D
V
is in opposite to transformer T
1
Positive voltage deviation D
< -B
Changing to lower tap of T
SIPROTEC 5, High-Voltage Bay Controller, Manual
so that the
CRCk
, caused by
CRCk
. This results for
2
V
with D
+ D
> B
1
V
CRC1
Circul.
C53000-G5040-C015-9, Edition 11.2017
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