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6.2.2.2
Transformer winding, earthed through zig-zag earthing transformer
M13048-8 v11
A common application is for low reactance earthed transformer where the earthing is through
separate zig-zag earthing transformers. The fault current is then limited to typical 800 to 2000
A for each transformer. The connection for this application is shown in figure
REFPDIF
- 1
I3PW1CT1
I3P
IdN/I
Protected
winding W1
I3PW2CT1
I3P
IdN/I
REFPDIF
- 2
Protected
winding W2
Earthing
transformer
IEC09000110-4-EN.vsd
IEC09000110-4-EN V2 EN-US
Figure 41: Connection of the low impedance Restricted earth-fault function REFPDIF for
a zig-zag earthing transformer
6.2.2.3
Autotransformer winding, solidly earthed
M13048-13 v9
Autotransformers can be protected with the low impedance restricted earth-fault protection
function REFPDIF. The complete transformer will then be protected including the HV side, the
neutral connection and the LV side. The connection of REFPDIF for this application is shown in
figure
.
Section 6
1MRK 505 343-UEN B
Differential protection
110
Application manual
Summary of Contents for Relion 670 series
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