Siemens SIPROTEC 7SD610 Manual page 43

Topological Data for Transformers (optional)
The statements under this margin heading refer to protected lines (cables or overhead lines) if a power trans-
former is situated within the protected zone, i.e. to models with transformer option and if address 143
TRANSFORMER has been set to YES (see Section 2.1.1.2). If no transformer is part of the protected zone, this
paragraph can be passed over.
The topological data enable to relate all measured quantities to the nominal data of the power transformer.
With address 1103 FullScaleVolt. you inform the device on the primary rated voltage (phase-to-phase) of
the transformer. The operational rated voltage is also needed for computing the current reference values of the
differential protection. Therefore, it is absolutely necessary to set the correct rated voltage for each end of
the protected object even if no voltages are applied to the device.
In general, select the rated voltage of the transformer winding facing the device. However, if a winding has a
voltage control range,do not use the rated voltage of that winding but the voltage that corresponds to the mean
value of the currents at the ends of the control range of the tap changer. In this way the fault currents caused
by voltage control are minimised.
Calculation example:
Transformer
For the regulated winding (110 kV) this results in:
Maximum voltage
Minimum voltage
Voltage to be set (address 1103)
The OPERATION POWER (address 1106) is the direct primary rated apparent power for transformers and other
machines. For transformers with more than two windings, state the winding with the highest rated apparent
power. The same operation power value must be set for each end of the protected object since it is the
basis for the current comparison at the ends.
The power must always be entered as primary value, even if the device is generally configured in secondary
values. The device calculates the primary rated current of the protected device from the reference power.
The VECTOR GROUP I (address 1162) is the vector group of the power transformer, always from the device's
perspective. The device which is used for the reference end of the transformer, normally the one at the high
voltage side, must keep the numerical index 0 (default setting). The relevant vector group index must be stated
for the other winding(s).
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
YNd5
35 MVA
110 kV / 25 kV
Y-winding with tap changer ±10 %
U = 121 kV
max
U = 99 kV
min
Functions
2.1 General
43