I_ANGL_B1_C1 and I_ANGL_C1_A1 do not show the same value of +120, the polarity
of one current transformer can be wrong. For instance, if the polarity of the current
transformer measuring IL2 is wrong, I_ANGL_A1_B1 shows -60 deg, I_ANGL_B1_C1
shows -60 deg and I_ANGL_C1_A1 shows +120 deg.
When the phase order and the angle values are correct, the angle values I_ANGL_A1_A2,
I_ANGL_B1_B2 and I_ANGL_C1_C2 usually show ±180 deg. There can be several
reasons if the angle values are not ±180 deg. If the values are 0 deg, the value given for CT
connection type is probably wrong. If the angle values are something else, the value for
Clock number can be wrong. Another reason is that the combination of Winding 1 type and
Winding 2 type does not match Clock number. This means that the resulting connection
group is not supported.
Example
If Winding 1 type is set to "Y", Winding 2 type is set to "y" and Clock number is set to "Clk
num 1", the resulting connection group "Yy1" is not a supported combination. Similarly if
Winding 1 type is set to "Y", Winding 2 type is set to "d" and Clock number is set to "Clk
num 0", the resulting connection group "Yd0" is not a supported combination. All the non-
supported combinations of Winding 1 type, Winding 2 type and Clock number settings
result in the default connection group compensation that is "Yy0".
4.3.2.6 CT connections and transformation ratio correction
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
Figure 262 and Figure 263.
• 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
Figure 264 and Figure 265.
• The default value of the CT connection type setting is "Type 1".
1MAC059074-MB A Section 4
Protection functions
615 series ANSI 527
Technical Manual
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