ABB RED615 Technical Manual page 358

Section 4
Protection functions
352
LV side (A): I = 5 MVA / (1.732 × 10.5 kV) = 274.9 A
nT_B
So the settings for CT ratio Corrections at HV (A) and LV (B) side are:
CT ratio Correction (A) = 200 A / 144.3 A = 1.386
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 IED currents are
opposite, the CT connection type setting parameter is "Type 1". The
connection examples of "Type 1" are as shown in the
186.
• If the positive directions of the winding 1 and winding 2 IED 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".
1YHT530004D05 D
Figure 185 and
Figure 187 and Figure 188.
Technical Manual
Figure
615 series