ABB REC650 - Section 3 REC650 Setting Examples; Setting Example When REC650 Is Used as Back-Up Protection in a Transformer Protection Application

Section 3 REC650 setting examples
3.1 Setting example when REC650 is used as back-up
protection in a transformer protection application
The application example has a 145/22 kV transformer as shown in figure 5.
1
1
1
3
3
Ph-Ph
145 kV 22 kV
ANSI11000121-1-en.vsd
REC650
Y
Y
Y
ANSI11000121 V1 EN
Figure 5: Two-winding HV/MV transformer, Y/Δ-transformer
Table 3: Typical data for the transformer application
The following data is assumed:
Item
Data
Transformer rated power SN 60 MVA
Transformer high voltage side rated voltage VN1 145 kV ±9 · 1.67 % (with on load tap changer)
Transformer low voltage side rated voltage VN2 22 kV
Transformer vector group YNd11
Transformer impedance voltage at tap changer mid
point: ek
12 %
Maximum allowed continuous overload 1.30 · SN
Phase CT ratio at 145 kV level 300/1 A
CT at 145 kV neutral 300/1 A
Phase CT ratio at 22 kV level 2 000/1 A
22 kV VT ratio
/
22
3
0 11
3
.
0 11
3
.
/
kV
Table continues on next page
1MRK 511 286-UUS A Section 3
REC650 setting examples
39
Application manual