The primary rated voltage (phase-to-phase) 370 UN BUSBAR is important for voltage-dependent protection
functions (such as overexcitation protection, voltage protection, frequency protection, power protection func-
tions). It also influences the calculation of the operational measured values.
The feeders of a busbar may be rated for different currents. For instance, an overhead line may be able to
carry higher load than a cable feeder or a transformer feeder. You can define a primary rated current for each
side (feeder) of the protected object; this current will be the reference for all referred values. These ratings
may differ from the rated currents of the associated current transformers which latter will be entered at a later
stage (current transformer data). Figure 2-12 shows the example of a busbar with 3 feeders.
Additionally, a rated current for the entire busbar as the main protected object can be determined. The
currents of all measuring locations assigned to the main object are converted such that the values of the
differential protection are referred to this rated current of the main protected object, here the busbar. If the
current rating of the busbar is known, set this rated current in address 371 I PRIMARY OP.. If no rated
current of the busbar is defined, you should select the highest of the rated currents of the sides (= feeders). In
Figure 2-12, the rated object current (busbar current) would be 1000 A.
[nennstrom-3-abzweige-st, 1, en_GB]
Figure 2-12 Rated current of the sides of a busbar with 3 feeders (set address 105 PROT. OBJECT = 3ph
Busbar)
The object data concern only data of the protected main object as defined in the topology. No data of the
sides which are not assigned are requested here. They will be entered at a later date (margin heading “Object
Data for Further Protected Objects”).
Under address 372 I PRIMARY OP S1, set the rated primary current of the feeder 1. As mentioned above,
the sides and the assigned measurement locations are identical for busbars.
The same considerations apply for the further sides:
•
Address 373 I PRIMARY OP S2 for side (feeder) 2,
•
Address 374 I PRIMARY OP S3 for side (feeder) 3,
•
Address 375 I PRIMARY OP S4 for side (feeder) 4,
•
Address 376 I PRIMARY OP S5 for side (feeder) 5.
Addresses 375 and 376, are omitted in 7UT613 and 7UT633 since these versions allow only for 3 sides.
Object Data with Busbars (1-phase Connection) with up to 7 or 9 or 12 Feeders
These busbar data are only required if the device is used for single-phase busbar differential protection. When
configuring the scope of functions (see Scope of Functions, address 105), the following must have been set:
PROT. OBJECT = 1ph Busbar. In cases other than that, these settings are not available. 7UT612 allows up
to 7 feeders, 7UT613 and 7UT633 allow up to 9 and 7UT635 allows up to 12 feeders.
With address 370 UN BUSBAR you inform the device of the primary rated voltage (phase-to-phase). This
setting has no effect on the protective functions but influences the displays of the operational measured
values.
The feeders of a busbar may be rated for different currents. For instance, an overhead line may be able to
carry higher load than a cable feeder or a transformer feeder. You can define a primary rated current for each
feeder of the protected object; this current will be the reference for all referred values. These ratings may
Functions
2.1 General
SIPROTEC 4, 7UT6x, Manual 59
C53000-G1176-C230-5, Edition 09.2016
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