ABB ret650 - Section 6 Differential Protection; Transformer Differential Protection; Functionality

Section 6 Differential protection
6.1 Transformer differential protection
6.1.1 Functionality
The Transformer differential protection, two-winding T2WPDIF and Transformer
differential protection, three-winding T3WPDIF are provided with internal CT ratio
matching and vector group compensation and settable zero sequence current
elimination.
The function can be provided with two or three three-phase sets of current inputs. All
current inputs are provided with percentage bias restraint features, making the IED
suitable for two- or three-winding transformer arrangements.
Two-winding applications
xx05000048.vsd
IEC05000048 V1 EN
two-winding power
transformer
Three-winding applications
xx05000052.vsd
IEC05000052 V1 EN
three-winding power
transformer with all
three windings
connected
xx05000049.vsd
IEC05000049 V1 EN
three-winding power
transformer with
unconnected delta
tertiary winding
Figure 29: CT group arrangement
for differential
protection and other
protections
The setting facilities cover the application of the differential protection to all types of
power transformers and auto-transformers with or without load tap changer as well as
shunt reactors and local feeders within the station. An adaptive stabilizing feature is
included for heavy through-faults.
1MRK 504 135-UEN A Section 6
Differential protection
79
Technical manual