ABB RER620 Technical Manual page 117

1MAC309294-MB F
RER620
Technical Manual
Figure 48: Two-phase short circuit, short circuit is between phases B and C
The equations are valid when network rotating direction is
counterclockwise, that is, ABC. If the network rotating direction is
reversed, 180 degrees is added to the calculated angle difference. This is
done automatically with a system parameter Phase rotation.
Negative-sequence voltage as polarizing quantity
When the negative voltage is used as the polarizing quantity, the angle difference between
the operating and polarizing quantity is calculated with the same formula for all fault
types:
 
= − −
ANGLE X _ ( V 2 ) ( )
This means that the actuating polarizing quantity is -V2.

−
I 2
RCA
Section 4
Protection functions
(Equation 1)
111