320°
200°
80°
AG sector
CG sector
BG sector
V2A
(Ref)
en06000384_ansi.vsd
ANSI06000384 V1 EN-US
Figure 115: Condition 1: Definition of faulty phase sector as angle between V
2
and I
0
The angle is calculated in a directional function block and gives the angle in radians as input to the
V
2
and I
0
function block. The input angle is released only if the fault is in forward direction. This is
done by the directional element. The fault is classified as forward direction if the angle between V
0
and I
0
lies between 20 to 200 degrees, see figure 116.
200°
Reverse
Forward
20°
en06000385.vsd
IEC06000385 V1 EN-US
Figure 116: Directional element used to release the measured angle between V
o
and I
0
The input radians are summarized with an offset angle and the result evaluated. If the angle is
within the boundaries for a specific sector, the phase indication for that sector will be active see
figure
115. 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
0
and I
0
as valid. The following conditions
must be fulfilled for activating the release signals:
|V
2
|>
V2MinOp
|3I
0
|> 0.05 ·
IBase
|3I
0
|>maxIph ·
INRelPG
Section 7 1MRK 502 066-UUS B
Impedance protection
248
Technical manual
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