Siemens SIPROTEC 7UT613 series Manual page 41

Overload
Protection 2
RTD-boxes for
Overload
RTD-box Type
Overexcitation
Protection
Reverse Power
Protection
7UT613/63x Manual
C53000-G1176-C160-2
lates the overtemperature in the protected object from the flowing current, with refer-
ence to the permissible temperature. This method is characterised by its easy han-
dling and a low number of setting values.
Detailed knowledge about the protected object, the environment and cooling is re-
quired for overcurrent protection with hot-spot calculation in accordance with IEC
60354; it is advisable in case of transformers with integrated temperature detectors.
For this method, set address to 142 THERM. OVERLOAD = IEC354. For further details
see section 2.9
In case of 7UT613/63x it is possible to use an additional overload protection. In case
of a transformer, for example, the overtemperature of two windings can thus be de-
tected by means of current measurement or, apart from a transformer, the windings of
a shunt reactor can be monitored. For THERM.OVERLOAD2 under address 144 select
from the same options as for the first overload protection.
If, in case of an overload with thermal replica, the coolant temperature must be taken
into consideration, or if an overload protection with hot-spot calculation in accordance
with IEC 60354 is used (address 142 THERM. OVERLOAD = th repl w. sens or
IEC354), at least one RTD-box 7XV5662–xAD must be connected at the service in-
terface or an additional interface of the device, which informs the device with regard
to the coolant temperature. The additional interface is set in address 190 RTD-BOX
INPUT. The possible interfaces are dependent on the version of 7UT613/63x (cf. Or-
dering Information and Accessories in the Appendix). Port C (service interface) is
available in all versions. Depending on the device version, Port D is also possible.
If RTD-boxes with 7UT613/63x are operated, set the number and type of transfer of
measuring locations (RTD = Resistance Temperature Detector) under address 191
RTD CONNECTION: 6 RTD simplex or 6 RTD HDX (with one RTD-box) or 12 RTD
HDX (with two RTD-boxes). The settings have to comply with those of the RTD-box.
Note
The assignment with regard to which temperature measuring point shall be used for
which overload protection will be effected later during setting of the protection func-
tions.
The overexcitation protection is used to detect increased overflux or overinduction
conditions in generators and transformers, especially in power station unit transform-
ers, which cause impermissible temperature rise in the iron. Note that the overexcita-
tion protection (address 143 OVEREXC. PROT.) can only be used if the device is
equipped with voltage measurement inputs and voltages are connected. This protec-
tion is not applicable for single-phase busbar protection (address105 PROT. OBJECT
= 1ph Busbar). For further details see section 2.11
The reverse power protection (address 150 REVERSE POWER) protects mainly a
turbine-generator unit during failure of energy to the prime mover. It can be applied,
for example, as disconnection criterion in the system. It can only be used in three-
phase protected objects, thus not at address 105 PROT. OBJECT = 1 phase
transf. or 1ph Busbar. The reverse current protection requires that the device is
connected to a voltage transformer set and, together with a connected current trans-
2.1 General
41