2.1 General
37
7UT613/63x Manual
C53000-G1176-C160-2
Parameter Group
Changeover Func-
tion
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 dif-
ferent groups of settings for the function parameters. During normal operation, a con-
venient 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 assign-
ment 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 gen-
erator or motor and a unit-connected power transformer (also with more than 2
windings), 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 especially to single-phase power transformers with 16.7 Hz
(traction
transformers). Single-phase transformers are generally treated as three-phase
protected objects.
• g60For auto-transformers
select PROT. OBJECT = Autotransf., regardless
whether the auto-transformer has one or more further separate 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 accessi-
ble and often provided with current transformers. 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.
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