ABB RED615 Technical Manual page 415

1YHT530004D05 D
615 series
Technical Manual
When injecting the currents in the high voltage winding, the angle values
I_ANGL_A1_B1, I_ANGL_B1_C1, I_ANGL_C1_A1, I_ANGL_A2_B2,
I_ANGL_B2_C2 and I_ANGL_C2_A2 have to show +120 deg. Otherwise the
phase order can be wrong or the polarity of a current transformer differs from the
polarities of the other current transformers on the same side.
If the angle values I_ANGL_A1_B1, I_ANGL_B1_C1 and I_ANGL_C1_A1
show -120 deg, the phase order is wrong on the high voltage side. If the angle
values I_ANGL_A2_B2, I_ANGL_B2_C2 and I_ANGL_C2_A2 show -120 deg,
the phase order is wrong on the low voltage side. If the angle values
I_ANGL_A1_B1, 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".
Recommendations for current transformers
The more important the object to be protected, the more attention has to be paid to
the current transformers. It is not normally possible to dimension the current
transformer so that they repeat the currents with high DC components without
saturating when the residual flux of the current transformer is high. TR2PTDF
operates reliably even though the current transformers are partially saturated.
The accuracy class recommended for current transformers to be used with
TR2PTDF is 5P, in which the limit of the current error at the rated primary current
is 1 percent and the limit of the phase displacement is 60 minutes. The limit of the
composite error at the rated accuracy limit primary current is 5 percent.
The approximate value of the accuracy limit factor F
current transformer burden can be calculated on the basis of the rated accuracy
Section 4
Protection functions
corresponding to the actual
a
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