2 Functions
16 7UT612 Manual
C53000–G1176–C148–1
The measuring input I7 serves often to acquire a starpoint current. Carrying out con-
figurations in address ,&7&211(&7 the de vice w ill be in fo rmed on the side
the current is assigned to. For transformers select the side where the starpoint is
earthed and where the starpoint current is to be measured. For earthed generators
and motors it is the side which is looking towards the earthed starpoint. For auto-trans-
formers any side can be selected since there is only one starpoint current for both
sides. If the starpoint current is not used for differential protection or for restricted earth
fault prote ction, pre-set the following: QRWXVHG.
If restricted earth fault protection is applied, it must be assigned to an earthed side in
address 5()3527. Otherwise this protection function has to be set to 'LVD
EOHG. For auto-transformers any side can be used.
The overcurrent time protection functions must also be assigned to a specific side of
the protected object.
−For ph a se ov er cu r re n t ti me protecti on se lect t h e s id e rel e va nt for this pr ote c ti on in
address '07,'073KDVH. For generators usually the starpoint side is select-
ed, for motors the terminal side. Otherwise, for single-side infeed we recommend
the feeding side. Often, however, an external overcurrent time protection is used for
the feeding side. The internal overcurrent time protection of 7UT612 should then be
activated for the outgoing side. It is then used as backup protection for faults be-
yond the outgoing side.
−To select the characteristic group according to which the phase overcurrent time
protection is to operate use address '07,'073+&+. If it is only used as
definite time overcurrent protection (DMT), set 'HILQLWH7LPH. In addition to the
definite time overcurrent protection an inverse time overcurrent protection may be
configured, if required. The latter operates according to an IEC-characteristic (72&
,(&), to an ANSI-characteristic (72&$16,) or to a user-defined characteristic. In
the latter case the trip time characteristic (8VHU'HILQHG38) or both the trip time
characteristic and the reset time characteristic (8VHUGHI5HVHW) are config-
ured. For the characteristics please refer to the Technical Data.
−In address the zero sequence (residual) current time overcurrent protection
'07,'07, can be assigned to any side of the protected object. This does not
have to be the same side as for phase overcurrent protection (address , see
above). For characteristics the same options are available as for the phase over-
current pr otecti on usi ng addre ss '07,'07,&+. However, for zero se-
quence current time overcurrent protection the settings may be different to the set-
tings selected for phase time overcurrent protection. This protection function always
acquires the residual current 3I0 of the supervised side. This current is calculated
from the sum of the corresponding phase currents.
−There is another earth current time overcurrent protection which is independent
from the before-described zero sequence time overcurrent protection. This protec-
tion, to be configured in address '07,'07(DUWK, acquires the current con-
nected to the current measuring input I7. In most cases, it is the starpoint current of
an earthed starpoint (for transformers, generators, motors or shunt reactors). No
assignment to a specific side is necessary since this type of protection always ac-
quires the I7 current, no matter where it originates from. For this protection you may
select one of the characteristic groups using address '07,'07(&+5, the
same way as for the phase time overcurrent protection. No matter which character-
istic has been selected for the latter.
A single-phase definite-time overcurrent protection '073+$6( for different user-
requirements is available in address . The protection function offers two options.