ABB RER670 Applications Manual page 206

Section 9
Voltage protection
200
UBase (given in GlobalBaseSel): Set as rated phase-to-phase voltage in primary
kV. This voltage is used as reference for voltage setting. O2RWPTOV measures
selectively phase-to-earth voltages, or phase-to-phase voltage chosen by the setting
ConnType. The function will operate if the voltage gets higher than the set
percentage of UBase. When ConnType is set to PhN DFT or PhN RMS, the IED
automatically divides set value of UBase by 2. When ConnType is set to PhPh DFT
or PhPh RMS, set value of UBase is used. Therefore, always set UBase as rated
primary phase-to-phase voltage of the protected object. This means operation for
phase-to-earth voltage over:
and operation for phase-to-phase voltage over:
> ×
U (%) UBase(kV)
EQUATION1993 V1 EN-US
Thus, for any selected measuring type setting of 100% corresponds to the rated
primary voltage.
The below described setting parameters are identical for the two steps (n = 1 and
2). Therefore the setting parameters are described only once.
OperationStepn: This is used to enable/disable the operation of step n.
OpModen: This parameter describes how many of the two measured voltages that
should be above the set level to give operation. The setting can be Any phase or All
phases. In most applications it is sufficient that one phase voltage is high to give
operation. If the function shall be insensitive for single phase-to-earth faults All
phases can be chosen, because the voltage will normally rise in the non-faulted
phases at single phase-to-earth faults.
Un>: This is used to set operate overvoltage operation value for step n, given as %
of UBase. The setting is highly dependent of the protection application. Here, it is
essential to consider the maximum voltage at non-faulted situations. In general, this
voltage is less than 110% of nominal voltage.
tn: time delay of step n, given in s. The setting is highly dependent of the protection
application. In many applications the protection function is used to prevent
damages to the protected object. The speed might be important for example in case
of protection of transformer that might be overexcited. The time delay must be co-
ordinated with other automated actions in the system.
1MRK 506 375-UEN A
(Equation 65)
Railway application RER670 2.2 IEC
Application manual