Toshiba GRL100-701B, Instruction Manual

Page: 140 / 473

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139
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6 F 2 S 0 8 5 0
Figure 2.16.3.8 Reactance Element
The setting of
θ
1(Z1
θ
1) and
θ
2(Z1
θ
2) are set to the following:
Z1
θ
2 < tan
-1
( X / R
F
)
Where,
X = reactance component
R
F
= fault resistance
Z1
θ
1 < tan
-1
{I
Lmax
/ (I
Lmax
+ I
Fmin
)}
I
Lmax
= maximum load current
I
Fmin
= minimum fault current
Blinder element
The blinder element is commonly applicable to Z1, Z2, Z3, ZR and Z4. As shown in Figure
2.16.3.9, the blinder element provides the forward blinder and the reverse blinder. The operating
area of the forward blinder is the zone enclosed by the lines BFR and BFL, and that of the reverse
blinder is the zone enclosed by the lines BRR and BRL. The BFR has an angle
θ
of 75
°
to the
R-axis and BFL 90
°
to 135
°
. The angle of BRL is linked with that of BFL.
(a) Forward blinder
(b) Reverse blinder
BRL
R
X
-Rs
θ
75
°
BRR
X
R
θ
75
°
BFR
BFL
R
Rs
X
Rs
Figure 2.16.3.9 Blinder element
The characteristic of the BFR is obtained by the following equation.
X
≥
(R
−
Rs) tan 75
°
where,
(b) Z2 and ZF
X
R
90
°
(a) Z1 and Z1X
θ
2
R
θ
1
X
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