ABB RELION REX640 Technical Manual page 654

Section 4
Protection functions
648
Commissioning
The settings for the connection group compensation (CT connection 1-2, Phase shift
Wnd 1-2 and, in case of a three-winding transformer, also CT connection 1-3 and
Phase shift Wnd 1-3 settings) can be verified by monitoring the angle values
(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_A1_A2, I_ANGL_B1_B2 and
I_ANGL_C1_C2 and in case of three-winding transformer also I_ANGL_A3_B3,
I_ANGL_B3_C3, I_ANGL_C3_A3, I_ANGL_A1_A3, I_ANGL_B1_B3 and
I_ANGL_C1_C3) when injecting the current into the transformer. These angle values
are calculated from the compensated currents.
When a station service transformer is available, it can be used to provide current into
the winding 1 side, for example, HV windings, while the winding 2 side, for example,
LV windings are short-circuited, as shown in
transformer, the tertiary winding side is short-circuited). This way the current can
flow both in high-voltage and low-voltage windings (and in winding 3 in case of three-
winding transformer). The commissioning signals can also be provided through other
means. The currents need to be at least 0.015 pu to allow the phase current and angle
monitoring.
A1
B1
C1
3 phase
low voltage
source
GUID-03A10C2B-213F-4346-8E5C-98D37280E69F V1 EN
Figure 361: Low-voltage test arrangement. The three-phase low-voltage source
can be the station service transformer, for example.
The control setting Tapped winding should be set to value "Not in use" to ensure that
the monitored current values are not scaled by the automatic adaptation to the tap
changer position. When only the angle values are taken, this is not needed since the
angle values are not affected by the tap changer position.
When injecting the currents into the HV 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, and in case of three winding transformer, I_ANGL_A3_B3,
I_ANGL_B3_C3 and I_ANGL_C3_A3, should be +120.
Otherwise, the phase order may be wrong or the polarity of one 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°,
the phase order is wrong on winding 1, for example, the high-voltage side. If the angle
Figure 361 (in case of a three-winding
YNyn0
1MRS759142 C
A2
B2
C2
REX640
Technical Manual