Three-Phase Faults - ABB REL650 series Technical Manual

1MRK 506 335-UUS A
6.2.6.3
Technical manual
<
3I IMinPUPG
0
EQUATION2109-ANSI V1 EN
INBlockPP
< ×
3 I
Iph max
0
100
EQUATION2110-ANSI V1 EN
where:
IMinPUPG
is the minimum operation current for ground measuring loops,
3I0BLK_PP is 3I
limit for blocking phase-to-phase measuring loop and
0
Iphmax is maximal magnitude of the phase currents.

Three-phase faults

The operation conditions for three-phase faults are the same as for phase-to-phase fault,
that is equation 30, equation
function.
However, the reach is expanded by a factor 2/√3 (approximately 1.1547) in all directions.
At the same time the characteristic is rotated 30 degrees, counter-clockwise. The
characteristic is shown in figure 55.
31 and equation 32 are used to release the operation of the
Section 6
Impedance protection
(Equation 31)
(Equation 32)
135