ABB RELION REX640 - Page 705

Vector group of
the transformer
Winding 1 type Winding 2 type Clock number Zro A
Elimination
ZNy1 ZN y Clk Num 1 Not needed
Zy5 Z y Clk Num 5 Not needed
Zyn5 Z yn Clk Num 5 Not needed
ZNyn5 ZN yn Clk Num 5 HV side
ZNy5 ZN y Clk Num 5 Not needed
Zy7 Z y Clk Num 7 Not needed
Zyn7 Z yn Clk Num 7 Not needed
ZNyn7 ZN yn Clk Num 7 HV side
ZNy7 ZN y Clk Num 7 Not needed
Yy0 Y y Clk Num 0 Not needed
Commissioning
The correct settings, which are CT connection type , Winding 1 type , Winding 2
type and Clock number , for the connection group compensation 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 while injecting the current into the transformer. These angle
values are calculated from the compensated currents. See signal description from
Monitored data table.
When a station service transformer is available, it can be used to provide current
to the high voltage side windings while the low voltage side windings are short-
circuited. This way the current can flow in both the high voltage and low voltage
windings. The commissioning signals can be provided by other means as well. The
minimum current to allow for phase current and angle monitoring is 0.015 I
r
.
Figure 400: Low voltage test arrangement. The three-phase low voltage source can
be the station service transformer.
The Tapped winding control setting parameter has to be set to “Not in use” to make
sure that the monitored current values are not scaled by the automatic adaptation
to the tap changer position. When only the angle values are required, the setting
of Tapped winding is not needed since angle values are not affected by the tap
changer position adaptation.
1MRS759142 F
Protection functions
REX640
Technical Manual
705