Hitachi Relion 670 Series Applications Manual page 84

Section 6
Differential protection
6.2.5 Setting examples
For the transformer in Figure 33, there are two solutions for balancing the transformer differential
protection.
U
132kV
V
IEC16000067 V1 EN-US
Figure 33:
Solution 1 (see Figure
Connection to the preprocessing blocks:
HV side: IL1=I
LV side: IL1=I
Settings within the transformer differential protection:
PhSelW1 = (IL1-IL2)/2
PhSelW2 = IL1
InvW2Curr = No
Solution 2 (see Figure
Connection to the preprocessing blocks:
HV side: IL1=I
LV side: IL1=0, IL2= I
Settings within the transformer differential protection:
PhSelW1 = (IL1-IL2)/2
PhSelW2 = IL2
InvW2Curr = Yes
Base current
The base current is calculated for each side (winding 1 and winding 2) of the power transformer:
78
I
U
I
v
A railway transformer with rating 16MVA, 132/15kV
39 for CT connections and ACT configuration):
; IL2=I
V U
, IL2= 0
S
40 for CT connections and ACT configuration):
; IL2=I
U V
S
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1MRK506375-UEN Rev. N
GUID-812455C4-D231-4E71-814F-E83FBBB0461B v1
R
15kV
I
s
S
IEC16000067-1-en.vsd
Railway application RER670
Application manual