NOTE
The available functions and default settings depend on the order variant of the device.
Special characteristics are set out in detail below. The annex includes a list of the functions with the suitable
protective objects.
Setting group switching
If the parameter group changeover function is desired, address 103 Grp Chge OPTION should be set to
Enabled. In this case, it is possible to apply up to four different groups of settings for the function parame-
ters. During normal operation, a convenient and fast switch-over between these setting groups is possible.
The setting Disabled implies that only one function parameter setting group can be applied and used.
Protected Object
The definition of the PROT. OBJECT (address 105) is important for the correct assignment of the setting
parameters and the possible inputs and outputs and functions of the device. This object is defined as the main
protected object which is intended to be protected by the differential protection. It should be mentioned here
that further parts of the power plant can be protected by other part functions if not all measured current
inputs of the device are necessary for the differential protection of the main protected object. The settings for
the protected object and the following protection functions are irrespective of how the protection functions
act on the protected object and which measuring locations (current transformers) are available.
•
Normal
Power transformers with separate windings are set as PROT. OBJECT = 3 phase transf.
regardless of the number of windings, vector groups and the earthing conditions of the starpoints. This is
also valid if a neutral earthing reactor is situated within the protected zone. If the differential protection
shall cover a generator or motor and a unit-connected power transformer (also with more than 2 wind-
ings), the protected object is also declared as transformer protection.
•
For PROT. OBJECT = 1 phase transf. phase input L2 is not connected. This option is suited espe-
cially to
single-phase power transformers with 16.7 Hz (7UT613/63x). Single-phase transformers are
generally treated as three-phase protected objects.
•
For auto-transformers select PROT. OBJECT = Autotransf., regardless whether the auto-transformer
has one or more further seperate windings. This option is also applicable for
shunt reactors if current
transformers are installed at both sides of the connection points.
•
If three single-phase auto-transformers are arranged as a power transformer bank (see Figure 2-1), the
connections of the starpoint leads of the windings are accessible and often provided with current trans-
formers. Here, it is possible, instead of a normal transformer differential protection via an entire power
transformer bank, to realise three single-phase current comparison circuits via each auto transformer
winding. In Figure 2-1 the protected zone of each phase is shaded.
Functions
2.1 General
SIPROTEC 4, 7UT6x, Manual 31
C53000-G1176-C230-5, Edition 09.2016
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