ABB RET 543 - Page 53

Fig. 8 Protection, control, measurement and supervision functions of a YNd-connected power trans-
former, implemented with an RET 543 transformer terminal, REF 543 feeder terminals and REA
101 arc protection. The low-voltage network is earthed via a zig-zag earthing transformer.
3
U
U
TCS
R
90
TT
LV
50N
O
3I >
2f
RET 54_
68
62BF
62BF
HV
CBFP
LV
CBFP
w
3I
0
3I
ΔI >
0
HV
ΔI >
0
LV
87TN
49T
87TN
3ΔI>
87T
0
I >
I >
HV
0
LV
3I>
51N
51N
50N
I
50
51
HV
3I>
50
51
U
I
0
HV
000
000
TCS
R
3I
3U
62BFCBFP
REF 54_
I >
0
50N
51N
f>
3U<
81O
27
3I> 67 3U> 59
I
0
3I-harm
pf
P
Q
f
&
3I>
3U-harm
E
REA 101
df/dt
81O-R
000
000
R
TCS
3U
3I
51N
0
I >
REF 54_
CBFP 62BF
50N
2f
3I >
3I>
68
50
51
3U<
3U>
27
59
I
0
M
M
MM
M
M
M
M
YNd transformer with earthing transformer on LV side
M M
MF
MF
P>
Θ
Θ
RET/3I
RET/3I
REF,REA/3I
RET/1U
REF/1I
RET/1I
RET/1I
REF/1I
REF/3U REF/3U
REF/3U REF/3U
REF/3I
Transformer Terminal RET 541, RET 543, RET 545
1MRS755543
53