ABB RELION 620 Series Technical Manual page 276

Section 4
Protection functions
270
GUID-C2EC2EF1-8A84-4A32-818C-6D7620EA9969 V1 EN
Figure 131: Two-phase short circuit, short circuit is between phases B and C
The equations are valid when network rotating direction is counter-
clockwise, 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 _ ( U )
= ϕ − − ϕ
2
GUID-470263DD-C1D7-4E59-B011-24D8D35BD52A V3 EN
( ) I
− ϕ
2 RCA
1MRS757644 F
(Equation 5)
620 series
Technical Manual