GE P645

Set the following parameters in the SY
STEM CONFIG column:
Setting in GROUP 1 SYSTEM CONFIG Value
Winding Config HV+LV
Winding Type Conventional
HV CT Terminals 01
LV CT Terminals 10
Ref Power S 90.00 MVA
Ref Vector Group 0
HV Connection Y-Wye
HV Grounding Grounded
HV Nominal 132.0 kV
HV Rating 90.00 MVA
% Reactance 10.00%
LV Vector Group 9
LV Connection D-Delta
LV Grounding Grounded
LV Nominal 33.00 kV
LV rating 90.00 MVA
Phase Sequence Standard ABC
VT Reversal No Swap
CT1 Reversal No Swap
CT2 Reversal No Swap
Vector correction and zero sequence filtering are automatically performed by virtue of the LV Vector Group setting
and the HV Gr
ounding and LV Grounding settings.
The ratio correction factors are calculated as follows:
K
I
S
V
K
amp T CT
nom T CT
ref
nom HV
a
,
,
,
.
1
1
6
3
3
400
90 10
3 132 10
1 016= =
×
× ×
=
mmp T CT
nom T CT
ref
nom LV
I
S
V
,
,
,
.
2
2
6
3
3
2000
90 10
3 33 10
1 270= =
×
× ×
=
where:
● S
r
ef
= common reference power for all ends
● K
amp
,
T1CT, T2CT
= ratio correction factor of T1 CT or T2 CT windings
● I
nom, T1CT, T2CT
= primary nominal currents of the main current transformers
● V
nom, HV,LV
= primary nominal voltage of HV or LV windings
These matching factors are also displayed in the SYSTEM CONFIG column (Match Factor CT1 and Match Factor
CT2)
Now set the current differential parameters as follows:
P64x Chapter 6 - Transformer Differential Protection
P64x-TM-EN-1.3 123