ABB RER670 - Page 90

HV side: IL1=I
V
; IL2=I
U
LV side: IL1=I
S
, IL2= 0
Settings within the transformer dif
ferential protection:
PhSelW1 = (IL1-IL2)/2
PhSelW2 = IL1
InvW2Curr = No
Solution 2 (see Figure
38 for CT connections and ACT configuration):
Connection to the preprocessing blocks:
HV side: IL1=I
U
; IL2=I
V
L
V side: IL1=0, IL2= I
S
Settings within the transformer dif
ferential 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:
1
1000
1121
W
SBase
I
BaseW A
UBase


IECEQUATION16075 V1 EN-US (Equation 4)
2
1000
2 1067
W
SBase
I
BaseW A
UBase


IECEQUATION16076 V1 EN-US (Equation 5)
where:
SBase Rated power of transformer [MVA]
UBase
W1
Rated phase-to-phase voltage of winding 1 [kV]
UBase
W2
Rated phase-to-phase voltage of winding 2 [kV]
The base currents for T1PPDIF functions are set under Global Base Values in
Parameter Setting tool.
Section 6 1MRK 506 375-UEN A
Differential protection
84 Railway application RER670 2.2 IEC
Application manual