Low Impedance Restricted Earth Fault Protection Refpdif; Identification; Application - ABB RELION 650 Series Applications Manual

Section 6
Differential protection
IEC vector group
Dyn11
YNd5
Dyn5
6.2 Low impedance restricted earth fault protection
REFPDIF
6.2.1

Identification

Function description
Restricted earth-fault protection,
low impedance
6.2.2

Application

A breakdown of the insulation between a transformer winding and the core or the tank may
result in a large fault current which causes severe damage to the windings and the transformer
core. A high gas pressure may develop, damaging the transformer tank.
Fast and sensitive detection of earth faults in a power transformer winding can be obtained in
solidly earthed or low impedance earthed networks by the restricted earth-fault protection.
78
Positive sequence no-load
voltage phasor diagram
Y
IEC06000562 V1 EN-US
Y
IEC06000563 V1 EN-US
Y
IEC06000564 V1 EN-US
IEC 61850
identification
REFPDIF
Required delta CT connection type on star side of the
protected power transformer and internal vector group
setting in the IED
DAC/Yy0
DAB/Yy6
DAC/Yy6
IEC 60617 ANSI/IEEE C37.2
identification device number
IdN/I
SYMBOL-AA V1 EN-US
1MRK 504 158-UEN A
IP14640-1 v6
M14843-1 v5
87N
IP14941-1 v1
M13940-3 v11
Application manual