ABB Relion 650 Series Technical Manual page 132

Section 5
Impedance protection
where:
|V | and |V
1
V1MinOP and V2MinOP
140°
AG sector
ANSI06000413 V1 EN-US
Figure 70: 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
CG
BG
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:
V1Level
|V |
1
and
I1LowLevel
|I |>
1
or
IMaxLoad
|I |>
1
126
| are the magnitude of the positive and negative sequence voltages.
2
are the setting parameters for positive sequence and negative sequence
minimum operating voltages.
CG sector
BG sector
260°
en06000413_ansi.vsd
and V
2
Condition 2 ⇒
CG
AG
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20°
V1A
(Ref)
angle relationship
1
Fault type
CG
BCG
1MRK 506 326-UUS B
SEMOD153832-174 v3
Line distance protection REL650
Technical manual