Siemens SIPROTEC 7UM62, Manual

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Power System Data 1
29
7UM62 Manual
C53000-G1176-C149-3
Nominal Values of
Voltage
Transformers At addresses
0221 Unom PRIMARY
and
0222 Unom SECONDARY
, information is
entered regarding the primary nominal voltage and secondary nominal voltages
(phase-to-phase) of the connected voltage transformers.
Voltage Connection
U
E
At address
0223 UE CONNECTION
the user specifies to the device which type of volt-
age is connected to the U
E
input. The device derives from this information the way of
processing the input signal. The U
E
input is used for either the various stator earth fault
protection functions or for rotor earth fault protection using rated frequency voltage in-
jection (see Section 2.30). Table 2-3 shows the interdependencies for each protection
function.
Transformation
Ratio U
E
For the conversion of the displacement voltage U
E
in primary quantities, the device
requires the primary/secondary transformation ratio of the transformer delivering the
U
E
voltage. With the exception of the rotor earth fault protection, the
0224 FACTOR
UE
has an impact on those protection functions which process the U
E
input directly, as
shown in Table 2-3. For this ratio
0224 FACTOR UE
the following general formula
applies :
In this context, U
VT, prim
is the primary voltage and U
E, sec
is the secondary
displacement voltage applied to the device. If a voltage divider is used, its divider ratio
also influences this factor. The following equation results for the example in Figure 2-
1b with the power system data selected there and an 1:5 voltage divider ratio:
Table 2-3 Setting Options for the UE Input and their Impact on the Protection Functions
Setting of
UE CONNECTION
(Addr. 0223)
90-%-Stator Earth
Fault Protection
(Section 2.26)
Stator Earth Fault
Protection with
3rd Harmonics
(Section 2.28)
100-%-Stator Earth
Fault Protection
(20 Hz)
(Section 2.29)
Rotor Earth Fault
Protection (R, fn)
(Section 2.30)
not connected Processing of U0
measured value
(precisely:
√
3 U0)
Determination of 3rd har-
monics from calculated
U0 voltage
(Only U0 3rd harm >
stage usable). – –
UE connected to
loading resistor Processing of U0
measured value
(precisely:
√
3 U0)
– Processing of UE input –
UE connected to any
transformer Processing of UE in-
put (e.g. earth fault
protection on trans-
former side) – – –
UE connected to
broken delta winding Processing of UE in-
put Processing of UE input Processing of UE input –
UE connected to
rotor Processing of U0
measured value
(precisely:
√
3 U0)
– – Processing of UE
input
UE connected to
neutral transformer Processing of UE in-
put Processing of UE input Processing of UE input –
U
VT, prim
U
E, sec
-----------------------
=
0224 FACTOR UE
6.3 kV 3
( ) ⁄
500 V 5
⁄
---------------------------------
=
0224 FACTOR UE
= 36.4