ABB REL650 Applications Manual page 62

Section 3
REL650 setting examples
56
X1 ≥ 1.1 · X1 (Zone2) = 1.1 · 44.2 = 48.5 Ω
4.2. Set X0 to 140 Ω
X0 ≥ 1.1 · X0 (Zone2) = 138.9 Ω
5. Set the fault resistance reach (phase-phase)
5.1. Set RFltFwdPP to 70 Ω
5.2. Set RFltRevPP to 70 Ω
The setting RFltFwdPP, RFltRevPP, RFltFwdPG and RFltRevPG shall cover zone
2 both for phase-to-phase short circuits and three-phase short circuits.
RFltFwdPP ≥ 1.1 · RFPP (Zone2) = 1.1 · 44 = 48.4 Ω
It shall also be clarified that zone 2 is covered also for three-phase short circuits
where the phase selection has a phase shift of 30º and an amplitude increase of
2 / 3 . The characteristic are shown in figure 11:
Phase-to-phase fault
0.5 RFltRevPP
ANSI10000188 V1 EN
Figure 11: Phase selection impedance characteristic for two phase and three
phase short circuits
The figure shows that 0.5 · RFltFwdPP is larger than zone 2 maximum reach.
This gives:
× ³ ×
0.5 RFltFwdPP 48
GUID-BA41A96A-8C76-4BD2-A9C7-C485F8BB5021-ANSI V1 EN
6. Set the fault resistance reach (phase-ground)
6.1. Set RFltFwdPG to 110 Ω
6.2. Set RFltRevPG to 110 Ω
RFltFwdPG≥ 1.1 · RFPE (Zone 2) = 1.1 · 100 = 110 Ω
X1
60
0.
0.5 RFltFwdPP
44
+ = Þ
o
cos(81.9 ) 28.8 RFltFwdPP
2
1MRK 506 334-UUS A
Three-phase-fault
4/ 3 X1
0.5 RFltFwdPP
2
=
K
3
30
ANSI10000188_en_1.vsd
³ W
57.6
Application manual
(Equation 18)