Toshiba GR200 Series - Page 1727

6F2S1914 (0.49)
GRL200 (Soft 033 & 037)
- 1704 -
addition to the current differential protection for the special case.
Therefore the condition shown in Table K-1 and Table K-2 should be replaced by that
in Table K-5 and Table K-6 respectively for “CASE 1”.
Table K-5 CT Requirement defined by V
k
(Special case)
Td [ms]
Requirement 1
Requirement 2
35
V
k
≧ I
fmax
(R
ct
+ R
2
)×3
V
k
≧ I
f_z1_max
(R
ct
+ R
2
)×6
50
V
k
≧ I
fmax
(R
ct
+ R
2
)×3
V
k
≧ I
f_z1_max
(R
ct
+ R
2
)×7
75
V
k
≧ I
fmax
(R
ct
+ R
2
)×4
V
k
≧ I
f_z1_max
(R
ct
+ R
2
)×8
100
V
k
≧ I
fmax
(R
ct
+ R
2
)×4
V
k
≧ I
f_z1_max
(R
ct
+ R
2
)×8
150
V
k
≧ I
fmax
(R
ct
+ R
2
)×8
V
k
≧ I
f_z1_max
(R
ct
+ R
2
)×8
Td [ms]
Requirement 3
Requirement 4
35
V
k
≧ I
f_rev_max
(Rct+ R
2
)×2
V
k
> Max{I
Lmax
+ I
fmin
/2, I
fmaxout
} ×(R
ct
+ R
2
)×14.4
50
V
k
≧ I
f_rev_max
(Rct+ R
2
)×3
V
k
> Max{I
Lmax
+ I
fmin
/2, I
fmaxout
}× (R
ct
+ R
2
)×20
75
V
k
≧ I
f_rev_max
(Rct+ R
2
)×6
V
k
> Max{I
Lmax
+ I
fmin
/2, I
fmaxout
}× (R
ct
+ R
2
)×28.8
100
V
k
≧ I
f_rev_max
(Rct+ R
2
)×6
V
k
> Max{I
Lmax
+ I
fmin
/2, I
fmaxout
}× (R
ct
+ R
2
)×36.8
150
V
k
≧ I
f_rev_max
(Rct+ R
2
)×6
V
k
> Max{I
Lmax
+ I
fmin
/2, I
fmaxout
} ×(R
ct
+ R
2
)×50.4
V
k
: Knee point voltage [V]
R
ct
: Secondary CT resistance [ohms]
R
2
: Actual secondary burden [ohms]
I
fmax
: Maximum secondary fault current
I
f_z1_max
: Maximum secondary fault current at the zone 1 reach point
I
f_rev_max
: Maximum secondary fault current for a close-up reverse fault
I
Lmax
: Maximum secondary load current
Max{I
Lmax
+ I
fmin
/2, I
fmaxout
}:
The larger of (I
Lmax
+ I
fmin
/2) and I
fmaxout
I
fmin
: Minimum fault current
I
fmaxout
: Maximum out-flowing fault current for the special condition