ABB REL650 series Technical Manual page 162

Section 6
Impedance protection
156
introduced so that the fault sectors will have the same angle boarders as for condition 1.
If the calculated angle between V
for that sector will be activated. The condition 2 is released if both the following
conditions are fulfilled:
|V |>V2MinOp
2
|V |>V1MinOp
1
where:
|V | and |V |
1 2
V1MinOP and V2MinOP
140°
CG sector
AG sector
BG sector
260°
ANSI06000413 V1 EN
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 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.
and V lies within one sector, the corresponding phase
2 1
are the magnitude of the positive and negative sequence voltages.
are the setting parameters for positive sequence and negative sequence
minimum operating voltages.
20°
V1A
(Ref)
en06000413_ansi.vsd
and V angle relationship
2 1
Fault type
CG
BCG
1MRK 506 335-UUS A
Technical manual