ABB REG670 - Page 331

TRZ1
IEC11000297-3-en.vsd
<
<
<
BLOCK
BLKZ
U3P
I3P
STZ1
OpModeZ1
Z1Fwd
Z1Rev
Comparator
ZL1L2
OPModeZ1
Z1Fwd
Z1Rev
Comparator
ZL2L3
Comparator
ZL3L1
OpModeZ1
Z1Fwd
Z1Rev
1
³
ImpedanceAng
ImpedanceAng
ImpedanceAng
t
tZ1
IEC11000297 V3 EN
Figure 148: Block diagram of zone 1
The functionality included in zone 1:
• Comparator to detect, if the operating impedance has entered inside zone 1 offset
mho characteristic.
• All three phase-to-phase loops are implemented separately.
• Forward and reverse reach values are provided in percentage of impedance base
value at generator.
• Operate time delay is provided.
Comparator characteristics
The comparator consists of offset mho characteristics. Three individual comparators
are provided in the three phase-to-phase loops. The offset mho characteristic is as
shown in figure
149.
1MRK502052-UEN B Section 7
Impedance protection
325
Technical manual