ABB REC650 ANSI, Applications Manual

Page: 48 / 370

3.1.2 Calculating settings for global base values GBASVAL
Each function uses primary base values as a reference for the settings. The base values are
defined in Global base values for setting GBASVAL function. It is possible to include up
to GBASVAL function. In this application GBASVAL instance 1 is used to define the
base for 145 kV inputs and GBASVAL instance 2 for 22 kV inputs.
For transformer protection it is recommended to set the base parameters according to the
power transformer primary rated values:
1. Set Global Base 1
1.1. Set
IBase to 239 A
1.2. Set VBase to 145 kV
1.3. Set SBase to 60 MVA ( SBase =√3· VBase · IBase )
2. Set Global Base 2
2.1. Set
IBase to 1575 A
2.2. Set VBase to 22 kV
2.3. Set SBase to 60 MVA ( SBase =√3· VBase · IBase )
There are six instances of global base GBASVAL function, each instance
includes the three parameters:
IBase , UBase , SBase . The GlobalBaseSel
setting which can be found in the different IED functions references a
specific instance of the GBASVAL function.
3.1.3 Calculating settings for instantaneous phase overcurrent
protection, HV-side, PHPIOC (50)
1. Set GlobalBaseSel to 1
The (HV) winding data should be related to Global base 1.
2. Set Pickup to 1000 % of IBase
The instantaneous phase overcurrent protection on the high voltage side is used for
fast trip ping during severe internal faults. The protection shall be selective with
respect to the protections of the outgoing 22 kV feeders. Therefore the maximum
145 kV current during a three-phase short circuit on the 22 kV side of the transformer
is calculated:
Section 3
1MRK 511 286-UUS A
REC650 setting examples
42
Application manual