Siemens SIPROTEC 7UT613 series Manual page 39

Restricted Earth
Fault Protection
Restricted Earth
Fault Protection 2
Dynamic Pickup
Switching for Over-
current Protection
Overcurrent Pro-
tection for Phase
Currents
Overcurrent Pro-
tection for Phase
Currents 2 and 3
Overcurrent Pro-
tection for Zero Se-
quence Currents
Overcurrent Pro-
tection for Zero Se-
quence Currents 2
and 3
7UT613/63x Manual
C53000-G1176-C160-2
The Restricted earth fault protection (address 113 REF PROT.) com-
pares the sum of the phase currents flowing into the three-phase protected object
together with the current flowing into the earthed starpoint. Further information is given
in section 2.3.
Note that this is not applicable to the protected object busbar (address 105 PROT.
OBJECT= 1ph Busbar and address 105 PROT. OBJECT= 3ph Busbar).
Likewise, address 114 REF PROT. 2 is valid for the second possible restricted earth
fault protection
The dynamic parameter switching (address 117 COLDLOAD PICKUP) permits tempo-
rary switching to alternative pickup values in case of overcurrent protection function
for phase currents, zero sequence currents and earth currents. Further information is
given in section 2.6.
To select the characteristic group according to which the phase overcurrent time pro-
tection is to operate use address 120 DMT/IDMT Phase. This protection is not
applicable for single-phase busbar protection (address105 PROT. OBJECT = 1ph
Busbar). If it is only used as definite time overcurrent protection (O/C), set Definite
Time. In addition to the definite time overcurrent protection an inverse time overcur-
rent protection may be configured, if required. The latter operates according to an IEC-
characteristic (TOC IEC), to an ANSI-characteristic (TOC ANSI) or to a user-defined
characteristic. In the latter case, the trip time characteristic (User Defined PU) or
both the trip time characteristic and the reset time characteristic (User def. Reset)
are configured. For the characteristics please refer to Technical Data.
In the case of 7UT613/63x it is possible to use two additional phase overcurrent pro-
tection functions. One overcurrent protection can thus be implemented independently
on various sides of the main protection object or three-phase measuring locations. In
the case of DMT/IDMT Phase2 a selection can be made under the address 130 from
the same options as for the first overcurrent protection. The same applies under
address 132 for DMT/IDMT Phase3. The selected options can be equal to or different
for all of the three overcurrent protection functions.
The type of characteristics used for the zero sequence (residual) overcurrent time pro-
tection can be set in address 122 DMT/IDMT 3I0. The same options are available as
for the phase overcurrent protection. However, for zero sequence current time over-
current protection the settings may be different to the settings 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 correspond-
ing phase currents. This measuring location may be different from that of the phase
overcurrent protection. Note that the zero sequence overcurrent protection is not pos-
sible on single-phase protected objects (address 105 PROT. OBJECT = 1 phase
transf. or 1ph Busbar).
At 7UT613/63x it is possible to use two additional zero sequence overcurrent protec-
tion functions. Zero sequence current can thus be detected independently on various
three-phase measuring locations. For DMT/IDMT 3I0 2 under address 134 the
same options can be selected again independently. The same applies under address
136 for DMT/IDMT 3I0 3. The selected options can be equal to or different from the
three overcurrent protection functions.
2.1 General
39