ABB REG670 - Operation Principle of Zone 2

IEC11000296-2-en.vsd
jXLLI ·21
ß
FwdZLLILLUUcomp 121211 ·-=
REVZLLILLUUcomp 121212 ·+=
FwdZLLI 121 ·
REVZLLI 121 ·-
RLLI ·21
IEC11000296 V2 EN
Figure 149: Simplified offset mho characteristics for L1-L2 fault in zone 1
Criteria: Operation occurs if 90° ≤ β ≤ 270°.
In the above characteristics, Z1Fwd and Z1Rev are the forward and reverse reach
percentage values and ImpedanceAng is the characteristic angle provided for the zone
1 operation region.
1 1 Z Fwd Z Fwd ImpedanceAng= Ð
IECEQUATION14000025 V2 EN (Equation 54)
1 1 Z Rev Z rev ImpedanceAng= Ð
IECEQUATION14000026 V2 EN (Equation 55)
Voltage and current phasors selected for phase-to-phase loops are:
Sl.No
Phase-to-phase 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
Operate time
The operate time delay for zone 1 can be provided using the setting tZ1.
7.10.7.2 Operation principle of zone 2
Figure 150 shows the function block diagram describing the functionality of zone 2.
Section 7 1MRK502052-UEN B
Impedance protection
326
Technical manual