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2 Functions
The address 225 serves to communicate the adaptation factor between the phase
Uph/Uen Adaption
Factor
voltage and the displacement voltage to the device. This information is relevant for
measured quantity monitoring.
If the voltage transformer set has e-n windings connected to the device (UE input), this
must be specified accordingly in address 223 (see above margin heading "UE Input").
Since transformation between voltage transformers usually is as follows:
with connected Uen voltage the Uph/Uen factor (secondary voltage, address 225 Uph
/ Udelta) must be set to 3/√3 = √3 = 1.73. For other transformation ratios, i.e. the
formation of the displacement voltage via an interconnected transformer set, the factor
must be corrected accordingly.
The nominal frequency of the system is set in Address 270 Rated Frequency. The
Rated System Fre-
quency
factory setting of the model variant must only be changed if the device is to be used
for a purpose other than intended when ordering.
Address 271 PHASE SEQ. is used to change the default phase sequence (L1 L2 L3
Phase Rotation
for clockwise rotation), if your power system permanently has an anti-clockwise phase
sequence (L1 L3 L2). A temporary reversal of rotation is also possible using binary
inputs (see Section 2.33).
Figure 2-3
The 272 SCHEME setting is used for specifying if the generator to be protected is op-
Operating Mode
erated in Unit transf. or in Busbar mode. This specification is important for stator
earth fault connection and for the inverse O/C time protection with undervoltage con-
sideration, as different voltages are used here, depending on the corresponding oper-
ating mode (see "Undervoltage Consideration" in Section 2.8).
36
Phase sequences
7UM61 Manual
C53000-G1176-C127-3
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