ABB Relion 670 Series Technical Reference Manual page 302

Section 6
Impedance protection
296
will be active see figure 150. Only one sector signal is allowed to be activated at the
same time.
The sector function for condition 1 has an internal release signal which is active if the
main sequence function has classified the angle between V
following conditions must be fulfilled for activating the release signals:
|V |>V2MinOp
2
|3I |> 0.05 · IBase
0
|3I |>maxIph · INRelPG
0
where:
V and IN
2
V2MinOp
maxIph
The angle difference is phase shifted by 180 degrees if the fault is in reverse direction.
The condition 2 looks at the angle relationship between the negative sequence voltage
V and the positive sequence voltage V
2
relationship, there is no need for shifting phases if the fault is in reverse direction. A
phase shift is introduced so that the fault sectors will have the same angle boarders as
for condition 1. If the calculated angle between V
corresponding phase 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
are the magnitude of the negative sequence voltage and zero-
sequence current (3I )
0
is the setting parameter for minimum operating negative sequence
voltage
is the maximum phase current
. Since this is a phase-to-phase voltage
1
2
are the magnitude of the positive and negative sequence voltages.
are the setting parameters for positive sequence and negative sequence
minimum operating voltages.
1MRK505222-UUS C
and I as valid. The
0 0
and V lies within one sector, the
1
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