The function group has interfaces to the following measuring points:
•
Two-winding transformer:
– Voltage, 3-phase
– Current, 3-phase (optional)
•
Three-winding transformer:
– 2 x voltage, 3-phase
– 2 x current, 3-phase (optional)
•
Grid coupling transformer:
– 2 x voltage, 3-phase
– 2 x current, 3-phase
Figure 8-97 shows these interfaces as a block structure.
[dwvocnti-060913-01.vsd, 2, en_US]
Figure 8-97 Structure of the Voltage Control Function Group
You can find the information and function measured values of the voltage controller in the DIGSI routing
matrix.
Function Description Voltage Controller
If the load is increased in an electricity-supply system, the voltage is reduced and vice versa. The power trans-
formers are usually equipped with transformer tap changers (OLTC) so as to keep the power-system voltage at
a constant level.
As a result, the transformer ratio is changed in predefined steps. Changes to the transformer taps cause the
voltage to change.
The Voltage control function is intended to control transformers with motor-operated transformer tap
changers.
This function is designed to control the following:
•
For two-winding transformers (2W): the voltage on the secondary circuit of the power transformer
•
For three-winding transformers (3W): the voltage of the secondary winding 1 or winding 2
•
For grid coupling transformers (GC): voltage of winding 1 or winding 2, selectively depending on the
power direction
Control operation is based on a step-by-step principle. To move the tap changer one position higher or lower,
a single control pulse is issued to the motor-drive mechanism of the tap changer. The length of the control
pulse can be set over a large range so as to handle the different types of tap-changer drives. The control pulse
is issued if the measured voltage deviates from the set reference value by more than the preset voltage range
for more than a given time period.
8.9.3
Control Functions
8.9 Voltage Controller
SIPROTEC 5, Overcurrent Protection, Manual 1195
C53000-G5040-C017-8, Edition 07.2017
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