ABB RED650 Technical Manual page 133

1MRK 505 394-UEN A
Line differential protection RED650 2.2 IEC
Technical manual
The plain Mho circle has the characteristic as in figure 49. The condition for
deriving the angle β is according to equation 6.
(
β = arg U − I
L L 1 2 L L 1 2
IECEQUATION15027 V1 EN-US
where
U
is the voltage vector difference between phases L1 and L2
L1L2
EN-US EQUATION1790 V2
I
is the current vector difference between phases L1 and L2
L1L2
EN-US EQUATION1791 V2
is the positive sequence impedance setting for phase-to-phase fault in zone direction
Z 1
set
For Zone 1,
Z 1 = R PPZ 1 1 + ⋅ j X PPZ
set
IECEQUATION15011 V1 EN-US
where
R1PPZ1
is the positive sequence resistive reach for phase-to-phase fault for zone 1
X1PPZ1 is the positive sequence reactance reach for phase-to-phase fault for zone 1
For Zone 2-5 and RV
Z 1 = R Zx 1 + ⋅ j X Zx 1
set
IECEQUATION15012 V1 EN-US
where
R1Zx
is the positive sequence resistive reach for zone x (x=2-5 and RV)
X1Zx
is the positive sequence reactance reach for zone x (x=2-5 and RV)
is the polarizing voltage
U
pol
Operation occurs if 90°≤β≤270°
) ( )
⋅ Z 1 − arg U
set pol
1 1
Section 7
Impedance protection
(Equation 6)
(Equation 7)
(Equation 8)
127