ABB REG670 - Page 335

ß
IEC11000300-2-en.vsd
112122Ucomp UL L IL L Z Fwd
212122Ucomp UL L IL L Z REV
12
I
LL R

12 2
I
L L Z REV
12
I
LL jX
12 2
I
LL Z Fwd
IEC11000300 V2 EN
Figure 153: Simplified offset mho characteristics for L1-to-L2 fault in zone 2
Operation occurs if 90° ≤ β ≤ 270°.
Impedance defined in the Figure
152 and 153 is described in equation 56.
2 2 Z Fwd Z Fwd ImpedanceAng= Ð
2 2 Z R Z Rev ImpedanceAngev = Ð
GUID-007D6357-B7CF-4C21-B772-2245F06C83A2 V2 EN (Equation 56)
Voltage and current phasors selected for different measuring loops:
Phase Phase:
Sl.No
Measuring Loop Voltage Phasor Current Phasor
1
L1-L2
1 2UL L
1 2IL L
2
L2-L3
2 3UL L
2 3IL L
3
L3-L1
3 1UL L
3 1IL L
Enhanced Reach:
1MRK502052-UEN B Section 7
Impedance protection
329
Technical manual