Installation and Commissioning
8-277SA522 Manual
C53000-G1176-C119-2
R, X both positive, when power flows into the line,
R, X both negative, when power flows towards the busbar.
The general case is assumed here, whereby the forward direction (measuring direc-
tion) extends from the busbar towards the line. In the case of capacitive load, caused
by e.g. underexcited generators or charging currents, the X-components may
all
have
the opposite sign.
If significant differences in the values of the various loops are present, or if the individ-
ual signs are different, then individual phases in the current or voltage transformer cir-
cuits are swapped, not connected correctly, or the phase allocation is incorrect. After
isolation of the line and short-circuiting of the current transformers the connections
must be checked and corrected. The measurement must then be repeated.
Finally the line must again be isolated.
8.3.3 Polarity check for the voltage input U4
Depending on the application of the voltage measuring input U4, a polarity check may
be necessary. If no measuring voltage is connected to this input, this subsection is ir-
relevant.
If the input U4 is used for measuring a voltage for overvoltage protection (Power
System Data 1 address 8WUDQVIRUPHU = 8[WUDQVIRUPHU), no polarity
check is necessary because the polarity is irrelevant here. The voltage magnitude was
checked according to Subsection 8.3.1.
If the input U4 is used for measuring the displacement voltage Uen (power system
data 1 address 8WUDQVIRUPHU = 8GHOWDWUDQVI), the polarity is checked
together with the measured current test according to Subsection 8.3.4.
If the input U4 is used for measuring a busbar voltage for synchronism check (power
system data 1 address 8WUDQVIRUPHU = 8V\QFWUDQVI), the polarity
must be checked as follows using the synchronism check function.
Only for synchro-
nism check
The device must be equipped with the synchronism and voltage check (dead-line/
dead-bus check) function which must be configured to HQDEOHG under address
(see section 5.1).
The voltage 8V\QF connected to the busbar must be specified correctly under ad-
dress 8V\QFFRQQHFW (see Subsection 6.1.1).
If there is no transformer between the two measuring points, address $
M8V\QF8OLQH must be set to (see Subsection 6.1.1).
If the measurement is made across a transformer, this angle setting must correspond
to the phase rotation through which the vector group of the transformer as seen from
the feeder in the direction of the busbar rotates the voltage. An example is shown in
Subsection 6.1.1.
If necessary different transformation ratios of the transformers on the busbar and the
feeder may have to be considered under address 8OLQH8V\QF.
The synchronism and voltage check must be switched RQ under address )&7
6\QFKURQLVP.
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