1 2 3 4 A - SIPROTEC

Functions
2.1 General
2.1 General
32
A few seconds after the device is switched on, the default display appears on the LCD. In the 7UT6x the
measured values are displayed.
The function parameters, i.e. function options, threshold values, etc., can be changed via the front panel of the
device, or via the operator or service interface from a personal computer using DIGSI. Password no. 5
(individual parameters) is required. Operation via DIGSI is described in the SIPROTEC system description /1/.
In this general section, you make the basic decision for the correct interaction between your system, its
measuring points, the analog device connections and the protective functions of the device. Because of the
comprehensive range of features provided by the devices of the 7UT6x family, this section is quite extensive.
The device here acquires as complete as possible a profile of the system to be protected with its measuring
locations, i.e. the current and voltage transformers, and which protective functions of the device are to take
effect in what way.
In a first step (Section 2.1.3), you specify which type of system element you want to protect, since the scope of
additional features offered varies depending on the type of main protected object. Then you decide which protection
functions you want to use, because not all of the functions integrated in the device are necessary, useful
or even possible for your relevant case of application.
In the next step (section 2.1.4), you describe the topology of the protected object. i.e. the arrangement of the
protected object, its sides (windings for transformers, sides for generators/motors, ends for lines, feeders for
busbars), and the measuring locations which will provide the respective measured values.
After entering some General Power System Data (frequency, phase sequence), you inform the device in
section 2.1.4 of the properties of the main protected object. Object properties include the ratings and (in the
case of transformers) the starpoint treatment, vector group and, where applicable, the auto-transformer
winding.
Subsection 2.1.4 also deals with the CT data which must be set to ensure that the currents acquired at the
various measuring locations are evaluated in the device with the correct scale factor.
The above information is sufficient to describe the protected object to the device's main protection function, i.e.
the differential protection. For the other protection functions, you select in section 2.1.6 the measured values
which will be processed by you and in which way.
The same section 2.1.6 provides information with regard to how to set the circuit breaker data, and finding out
about setting groups and how to use them. Last but not least, you can set general data which are not dependent
on any protection functions.
SIPROTEC, 7UT6x, Manual
C53000-G1176-C230-2, Release date 06.2012