ABB RELION REX640 Technical Manual page 568

Section 4
Protection functions
562
CT ratio correction (B) = 300 A / 274.9 A = 1.091
CT connections
The connections of the primary current transformers are designated as "Type 1" and
"Type 2".
• If the positive directions of the winding 1 and winding 2 protection relay currents
are opposite, the CT connection type setting parameter is "Type 1". The
connection examples of "Type 1" are as shown in the
• If the positive directions of the winding 1 and winding 2 protection relay currents
equate, the CT connection type setting parameter is "Type 2". The connection
examples of "Type 2" are as shown in the
• The default value of the CT connection type setting is "Type 1".
Figure 309 and
Figure 311 and Figure 312.
Technical Manual
1MRS759142 C
Figure 310.
REX640