ABB ret650, Applications Manual

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3
U
0
UL
1
IEC07000190-2-en.vsd
IEC07000190 V2 EN-US
Figure 59: Earth fault in Non-effectively earthed systems
8.3.3.5 Direct earthed system
GUID-EA622F55-7978-4D1C-9AF7-2BAB5628070A v8
In direct earthed systems, an earth fault on one phase is indicated by voltage
collapse in that phase. The other healthy phase will still have normal phase-to-earth
voltage. The residual sum will have the same value as the remaining phase-to-earth
voltage, which is shown in Figure
60 .
UL
1
IEC07000189-2-en.vsd
IEC07000189 V2 EN-US
Figure 60: Earth fault in Direct earthed system
1MRK 504 169-UEN A
Section 8
Voltage protection
Transformer protection RET650 2.2 IEC 153
Application manual