ABB Relion 670 Series Technical Reference Manual page 303

1MRK505222-UUS C
Technical reference manual
140°
CG sector
AG sector
BG sector
260°
ANSI06000413 V1 EN
Figure 152: Condition 2: V
If both conditions are true and there is sector match, the fault is deemed as single phase-
to-ground. If the sectors, however, do not match the fault is determined to be the
complement of the second condition, that is, a phase-to-phase-to- ground fault.
Condition 1 and Condition 2 ⇒
CG CG
BG AG
The sequence phase selector is blocked when ground is not involved or if a three-phase
fault is detected.
Three-phase fault detection
Unless it has been categorized as a single or two-phase fault, the function classifies it
as a three-phase fault if the following conditions are fulfilled:
|V |V1Level
1
and
|I |>I1LowLevel
1
or
|I |>IMaxLoad
1
20°
V1A
(Ref)
en06000413_ansi.vsd
and V angle relationship
2 1
Fault type
CG
BCG
Section 6
Impedance protection
297