Siemens SIPROTEC 7UT613 series Manual page 71

Current Transform-
er Data for 3-phase
Measuring Loca-
tions
7UT613/63x Manual
C53000-G1176-C160-2
which relate to the non-assigned measuring locations, according to the set topology.
Since the main protected object provides at least 2 measuring locations (differential
protection would make no sense with fewer), M1 and M2 will never appear here.
Address 403 I PRIMARY OP M3 requests the rated primary operating current at the
measuring location M3 provided this is not assigned to the main protected object.
Address 404 I PRIMARY OP M4 requests the rated primary operating current at the
measuring location M4 provided this is not assigned to the main protected object.
Address 405 I PRIMARY OP M5 requests the rated primary operating current at the
measuring location M5 provided this is not assigned to the main protected object.
Addresses 404 and 405, are omitted in 7UT613 and 7UT633 since these versions
allow only 3 measuring locations.
Voltage data have only a meaning in 7UT613 or 7UT633 if the device is equipped with
voltage inputs. In case the 3-phase voltage inputs relate to the main protected object,
the rated voltages have already been set. But, if 3-phase voltage measurement is in-
tended at a measuring location which is not assigned to the main protected object, e.g.
in address 261 VT SET a non-assigned Measuring loc.3 is selected, then you
have to enter the rated voltage of this measuring location in address 408 UN-PRI M3.
This is a precondition for correct display and transmission of measured values (volt-
ages, powers). Similar considerations apply to address 409 UN-PRI U4.
The rated primary operational currents for the protected object and its sides derive
from the object data. The data of the current transformer sets at the sides of the pro-
tected object generally differ slightly from the object data before-described. They can
also be completely different. Currents have to have a clear polarity to ensure correct
function of the differential protection and restricted earth fault protection as well as for
correct display of operational measured values (power etc.).
Therefore the device must be informed about the current transformer data. For 3-
phase protected objects, this is done by entering rated currents and the secondary
starpoint position of the current transformer sets.
In address 512 IN-PRI CT M1 the rated primary current of the current transformer
set of measuring location M1 is set, in address 513 IN-SEC CT M1 the rated second-
ary current. Please make sure that the sides were defined correctly (see subsection
2.1.4.1, margin heading „Assignment of 3-phase Measuring Locations"). Please also
make sure that the rated secondary transformer currents match the setting for the
rated currents of these measuring inputs of the device. Otherwise the device will cal-
culate incorrect primary data, and malfunction of the differential protection may occur.
Indication of the starpoint position of the current transformers determines the polarity
of the currents. To inform the device of the starpoint position in relation to the measur-
ing location 1, use address 511 STRPNT->OBJ M1 (starpoint versus object: YES or
NO). Figure 2-13 shows some examples for this setting.
2.1 General
71