Common base IED values for primary current (IBase), primary voltage (UBase)
and primary power (SBase) are set in the global base values for settings function
GBASVAL.
GlobalBaseSel
: This is used to select GBASVAL function for reference of base
values.
ConnType: Sets whether the measurement shall be phase-to-earth fundamental
value, phase-to-phase fundamental value, phase-to-earth RMS value or phase-to-
phase RMS value.
Operation: This is used for undervoltage protection Off/On.
UBase (given in GlobalBaseSel): Set as rated phase-to-phase voltage in primary
kV. This voltage is used as reference for voltage setting. U2RWPTUV measures
selectively phase-to-earth voltages, or phase-to-phase voltage chosen by the setting
ConnType. The function will operate if the voltage becomes lower than the set
percentage of UBase. When ConnType is set to PhN DFT or PhN RMS, the IED
automatically divides set value for UBase by 2. UBase is used as set when
ConnType is set to PhPh DFT or PhPh RMS. Therefore, always set UBase as rated
primary phase-to-phase voltage of the protected object. This means operation for
phase-to-earth voltage under:
IECEQUATION048 V1 EN-US (Equation 62)
and operation for phase-to-phase voltage under:
EQUATION1990 V1 EN-US (Equation 63)
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 on/off the operation of step n.
OpModen: This parameter describes how many of the two measured voltages
should be below the set level to give operation for step n. The setting can be Any
phase or All phases.
Un<: It is used to set undervoltage operation value for step n, given as %UB. The
setting is highly dependent on the protection application.
tn: time delay of step n, given in s. This setting is dependent on the protection
application. In many applications the protection function shall not directly trip
when there is a short circuit or earth faults in the system. The time delay must be
coordinated to the other short circuit protections.
1MRK 506 375-UEN A Section 9
Voltage protection
Railway application RER670 2.2 IEC 197
Application manual
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