Directional Lines - ABB Relion 670 Series Technical Reference Manual

Section 6
Impedance protection
6.5.2.5
268
w 2 p f × ×
=
0 0
EQUATION356 V1 EN
where:
Re designates the real component of current and voltage,
Im designates the imaginary component of current and voltage and
f designates the rated system frequency
0
The algorithm calculates Rm measured resistance from the equation for the real value
of the voltage and substitute it in the equation for the imaginary part. The equation for
the Xm measured reactance can then be solved. The final result is equal to:
× D -
Im (V) Re (I) Re (V)
=
R
m
D × - D
Re (I) lm(I)
EQUATION1550 V1 EN
×
Re (V) lm(I) lm(V ) Re (I)
× D ×
t
= w
X
0
m
D ×
Re (I) lm(I)
EQUATION1551 V1 EN
The calculated R and X
m
zone reach. The adaptive tripping counter counts the number of permissive tripping
results. This effectively removes any influence of errors introduced by the capacitive
voltage transformers or by other factors.
The directional evaluations are performed simultaneously in both forward and reverse
directions, and in all six fault loops. Positive sequence voltage and a phase locked
positive sequence memory voltage are used as a reference. This ensures unlimited
directional sensitivity for faults close to the IED point.

Directional lines

The evaluation of the directionality takes place in the Directional impedance element
for mho characteristic ZDMRDIR (21D) function. Equation
the fault is in forward direction for line-to-ground fault.
× D
lm(I)
×
lm(I) Re (I)
- ×
- D ×
lm(I) Re (I)
values are updated each sample and compared with the set
m
1MRK505222-UUS C
(Equation 46)
(Equation 47)
(Equation 48)
49 is used to classify that
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