ABB Relion 650 Series Technical Manual page 85

1MRK 506 326-UUS B
IEC10000175 V1 EN-US
Figure 36: Directional operating modes of the distance measuring zones
5.1.6.3 Minimum operating current
The operation of Five zone distance protection, quadrilateral characteristic (ZQDPDIS) is blocked
if the magnitude of input currents fall below certain threshold values.
The phase-to-ground loop AG (BG or CG) is blocked if IA (IB or IC) <
For zone 1 with load compensation feature the additional criterion applies, that all phase-to-
ground loops will be blocked when IN <
IA (IB or IC) is the RMS value of the current in phase IA (IB or IC). IN is the RMS value of the vector
sum of the three-phase currents, that is, residual current 3I
The phase-to-phase loop AB (BC or CA) is blocked if I
5.1.6.4 Measuring principles
Fault loop equations use the complex values of voltage, current, and changes in the current.
Apparent impedances are calculated and compared with the set limits. The apparent impedances
at phase-to-phase faults follow equation
V
=
Z
app
I
A
EQUATION1545 V1 EN-US
Line distance protection REL650
Technical manual
X
R
Offset
All three current limits
reduced to 75% of regular set values if the zone is set to operate in reverse
direction, that is,
- V
A B
- I
B
© Copyright 2011 ABB Power Grids. All rights reserved
X
R
Forward
IMinOpIR , regardless of the phase currents.
AB (BC or CA)
IMinPUPG , IMinOpIR and IMinPUPP are automatically
DirModex = Reverse (where x is 1-5 depending on selected zone).
1 (example for a phase A to phase B fault).
Impedance protection
X
R
Reverse
IEC10000175-1-en.vsd
IMinPUPG .
.
0
IMinPUPP .
<
Section 5
M16923-127 v4
M16923-4 v4
(Equation 1)
79