Siemens SIPROTEC 4 7UT6 Series Manual page 64

Functions
2.1 General
For rated secondary currents please make sure that rated secondary transformer currents match with the rated
current of the corresponding current input of the device. Rated secondary currents of a device can be
matched. If summation transformers are used, the rated current at the outgoing side is usually 100 mA. For
rated secondary currents a value of 0.1 A is therefore set for all feeders.
Indication of the starpoint position of the current transformers determines the polarity of the current trans-
formers. Set for each feeder if the starpoint is looking towards the busbar or not.
example of 3 feeders in which the transformer starpoint in feeder 1 and feeder 3 are looking towards the
busbar, unlike feeder 2.
If external interposed transformers are used, it is presumed that these are connected with correct polarity.
[anlagendaten-beispiel4-020904-st, 1, en_GB]
Figure 2-15
The parameters for the individual feeders are:
Feeder 1
•
Address 561 STRPNT->BUS I1 = transformer starpoint versus busbar for feeder 1,
•
Address 562 IN-PRI CT I1 = rated primary transformer current for feeder 1,
•
Address 563 IN-SEC CT I1 = rated secondary transformer current for feeder 1.
Feeder 2
•
Address 571 STRPNT->BUS I2 = transformer starpoint versus busbar for feeder 2,
•
Address 572 IN-PRI CT I2 = rated primary transformer current for feeder 2,
•
Address 573 IN-SEC CT I2 = rated secondary transformer current for feeder 2.
Feeder 3
•
Address 581 STRPNT->BUS I3 = transformer starpoint versus busbar for feeder 3,
•
Address 582 IN-PRI CT I3 = rated primary transformer current for feeder 3,
•
Address 583 IN-SEC CT I3 = rated secondary transformer current for feeder 3.
Feeder 4
•
Address 591 STRPNT->BUS I4 = transformer starpoint versus busbar for feeder 4,
•
Address 592 IN-PRI CT I4 = rated primary transformer current for feeder 4,
•
Address 593 IN-SEC CT I4 = rated secondary transformer current for feeder 4.
64
Position of the CT starpoints — example for phase L1 of a busbar with 3 feeders
Figure 2-15 shows an
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016