Siemens SIPROTEC 4 7VK61 - Polarity Check for the Voltage Input U

[lastscheinleistung-110402-wlk, 1, en_GB]
Figure 3-24 Apparent Load Power
The power measurement provides an initial indication as to whether the measured values have the correct
polarity. If both the active power as well as the reactive power have the wrong sign, the polarity in address
201 CT Starpoint must be checked and rectified.
Finally, switch off the protected power line.
Polarity Check for the Voltage Input U
4
Depending on the application of the voltage measuring input U
4
, a polarity check may be necessary. If no
measuring voltage is connected to this input, this section is irrelevant.
If the input U
4
is used for measuring a voltage for overvoltage protection (P.System Data 1 address 210 U4
transformer = Ux transformer), no polarity check is necessary because the polarity is irrelevant here.
The voltage magnitude was checked before.
If the input U
4
is used for the measurement of the displacement voltage U
en
(P.System Data 1 address 210
U4 transformer = Udelta transf.), the polarity together with the current measurement is checked (see
below).
If input U
4
is used for measuring a voltage for synchronism check (P.System Data 1 address 210 U4
transformer = Usy2 transf.), the polarity must be checked as follows using the synchronism check func-
tion.
Only for Synchronism Check
The device must be equipped with the synchronism and voltage check function which must be configured
under address 135 Enabled (see section 2.1.1.2 Setting Notes).
The synchronisation voltage U
sy2
must be entered correctly at address 212 Usy2 connection (see Section
2.1.3.1 Setting Notes).
If there is no transformer between the two measuring points, address 214 φ Usy2-Usy1 must be set to0°
(see Section 2.1.3.1 Setting Notes).
If the measurement is made across a transformer, this angle setting must correspond to the phase rotation
resulting from the vector group of the transformer (see also the example in Section2.1.3.1 Setting Notes).
If necessary, different transformation ratios of the transformers may have to be considered from both meas-
uring points U
sy1
and U
sy2
at address 215 Usy1/Usy2 ratio.
The synchronism and voltage check must be switched ON under address 3501 FCT Synchronism.
An additional help for the connection check are the messages 2947
Sync. Udiff> and 2949 Sync. φ-
diff> in the spontaneous annunciations.
3.3.8
Mounting and Commissioning
3.3 Commissioning
SIPROTEC 4, 7VK61, Manual 217
C53000-G1176-C159-5, Edition 05.2018