ABB RELION REX640 Technical Manual page 739

1MRS759142 F
Angle output name
I_ANGL_C1_C2
I_ANGL_A1_A3
I_ANGL_B1_B3
I_ANGL_C1_C3
Table 670: Angle outputs when settings CT connection 1-2 and CT connection 1-3
match the actual CT connections on windings 1, 2 and 3 but the phase B polarity is
wrong compared to other phases on winding 2
Angle output name
I_ANGL_A1_B1
I_ANGL_B1_C1
I_ANGL_C1_A1
I_ANGL_A2_B2
I_ANGL_B2_C2
I_ANGL_C2_A2
I_ANGL_A3_B3
I_ANGL_B3_C3
I_ANGL_C3_A3
I_ANGL_A1_A2
I_ANGL_B1_B2
I_ANGL_C1_C2
I_ANGL_A1_A3
I_ANGL_B1_B3
I_ANGL_C1_C3
4.3.3.8 Recommendations for current transformers
The more important the object to be protected, the more attention should be
paid to the CTs. Normally, it is not possible to dimension the CTs so that they
repeat currents with high DC components without saturating when the residual
flux of the current transformer is high. TR3PTDF operates reliably even though
the CTs are partially saturated. The purpose of the following current transformer
recommendations is to secure the stability of the relay at high through-currents and
the quick and sensitive operation of the relay at faults occurring in the protected
area where the fault currents can be high.
The accuracy class recommended for CTs to be used with TR3PTDF is 5P, where 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
CT burden can be calculated on the basis of the rated accuracy limit factor F
REX640
Technical Manual
Angle value
±180
±180
±180
±180
Angle value
+120
+120
+120
–60
–60
+120
+120
+120
+120
±180
0
±180
±180
±180
±180
Protection functions
Possible reason if not OK
OK
OK
OK
OK
Possible reason if not OK
OK
OK
OK
Wrong polarity phase B
Wrong polarity phase B
OK
OK
OK
OK
OK
Winding 2, wrong polarity
phase B
OK
OK
OK
OK
corresponding to the actual
a
(ALF)
n
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